A devastating disease called Huanglongbing(HLB) or citrus green is wiping out citrus trees across the globe. But we are seeing new hope. Scientists have recently uncovered a hidden battle happening inside citrus plant...A devastating disease called Huanglongbing(HLB) or citrus green is wiping out citrus trees across the globe. But we are seeing new hope. Scientists have recently uncovered a hidden battle happening inside citrus plants. Understanding this microscopic tug-of-war could be the key to rescuing our beloved oranges, lemons, and grapefruits.展开更多
Asian citrus psyllid(ACP)is a significant pest of citrus crops that can transmit citrus Huanglongbing(HLB)by feeding on the phloem sap of citrus plants,which poses a significant threat to citrus production.Volatile si...Asian citrus psyllid(ACP)is a significant pest of citrus crops that can transmit citrus Huanglongbing(HLB)by feeding on the phloem sap of citrus plants,which poses a significant threat to citrus production.Volatile signal chemicals with plant communication functions can effectively enhance the resistance of recipient plants to herbivorous insects with minimal impacts on plant growth.While(E)-4,8-dimethyl-1,3,7-nonatriene(DMNT),(E,E)-4,8,12-trimethyl-1,3,7,11-tridecene(TMTT),(E)-β-caryophyllene,and dimethyl disulfide(DMDS),are known as signaling molecules in guava-sweet orange communication,whether these four chemical signals can enhance the resistance of Citrus sinensis to feeding by ACP adults with no apparent costs in terms of plant growth remains unclear.Therefore,this study measured the effect of non-damaging induction by DMNT,TMTT,(E)-β-caryophyllene,and DMDS on the ability of C.sinensis to resist feeding by ACP,as well as their impacts on the defensive phytochemicals,defensive enzymes,functional nutrients,Photosystem II's utilization and allocation of light energy,photosynthetic pigments,growth conditions,and leaf stomatal aperture in C.sinensis.The results indicate that non-damaging induction by these four chemicals can enhance the activity of the defensive enzyme polyphenol oxidase(PPO)and increase the contents of total phenols,tannins,and terpenoid defensive phytochemicals within C.sinensis,thereby enhancing the resistance of C.sinensis to ACP feeding.Specifically,DMNT and DMDS exhibit more significant effects in inducing resistance compared to TMTT and(E)-β-caryophyllene.The characteristics of chlorophyll fluorescence parameters and changes in photosynthetic pigments in C.sinensis during different post-exposure induction periods revealed these chemicals can maintain the stability of the photosynthetic system in C.sinensis and regulate its capacity to capture,transmit,and distribute light energy,which significantly enhances the non-photochemical quenching ability of C.sinensis.In addition,detailed measurements of the water content,leaf mass per unit area(LMA),functional nutrients(soluble protein,soluble sugar,and amino acids),and stomatal parameters in C.sinensis leaves further indicated that the non-destructive induction by these chemicals can optimize the levels of functional nutrients in C.sinensis,primarily manifesting as the upregulation of soluble sugars,proline,or soluble proteins,and reduction of stomatal area and aperture,which maintains a stable leaf water content and LMA,thereby enhancing resistance to ACP while sustaining the healthy growth of C.sinensis.These results fully substantiate that the non-damaging induction by the signal chemicals DMNT,TMTT,(E)-β-caryophyllene,and DMDS can enhance the resistance of C.sinensis to ACP feeding while maintaining the balance between pest resistance and growth.This balance prevents any catastrophic effects on the growth of C.sinensis,so these agents can potentially be integrated with other pest management strategies for the collective protection of crops.This study provides theoretical support and assistance for the development of signal chemical inducers for the prevention and management of ACP in agricultural systems.展开更多
Chlorophyll degradation and carotenoid accumulation are essential processes of fruit maturation in many horticultural plants,and play a crucial role in fruit color and quality.The pathways of chlorophyll and carotenoi...Chlorophyll degradation and carotenoid accumulation are essential processes of fruit maturation in many horticultural plants,and play a crucial role in fruit color and quality.The pathways of chlorophyll and carotenoid biosynthesis and degradation are well understood,and key regulatory genes controlling these pathways have been identified in citrus.This article reviewed the recent research on chlorophyll and carotenoid metabolism in citrus fruits,encompassing the metabolic pathways,transcriptional regulation,influencing factors,and the interplay between chlorophyll and carotenoid metabolism,aiming to provide insights into the molecular regulatory mechanisms governing the coloration of citrus fruits.展开更多
Polyembryony has posed a significant impediment to the advancement of citrus hybrid breeding.FhRWP is widely regarded as a pivotal factor governing asexual reproduction in citrus,and prior research has demonstrated th...Polyembryony has posed a significant impediment to the advancement of citrus hybrid breeding.FhRWP is widely regarded as a pivotal factor governing asexual reproduction in citrus,and prior research has demonstrated that FhARID1,acting as an upstream regulator,modulates FhRWP expression.In this study,we performed a genome-wide characterization of the ARID-HMG-related genes using the short juvenile minicitrus Fortunella hindsii.A total of 20 ARID-HMG-related genes were identified.Protein interaction network and enrichment analysis suggested that ARID-HMG-related proteins might might be involved in chromatin remodeling complexes.Knockout of FhARID1 in F.hindsii did not induce the conversion from polyembryony to monoembryony.However,fharid1 plants in T1 generation exhibited abnormal proliferation at axillary buds,which is similar to phenotype of fhrwp plants.Expression analysis of fharid1 ovary tissues revealed the downregulation of FhRWP.The results indicated that FhARID1,as an upstream regulator of FhRWP,has an effect on the development of citrus axillary buds.Expression analysis of overexpressed leaves of FhARID1 lines showed that no significant up-regulation of FhRWP,indicating that FhARID1 is not the sole upstream regulatory factor of FhRWP.Only FhARID2 showed a correlation in expression with FhARID1 among the ARID-related genes,further supporting the notion that this gene may be involved in complex formation rather than acting alone.Yeast two-hybrid and MS/MS spectra further indicated that FhARID1 function requires casein kinase II-mediated post-transcriptional phosphorylation.This study elucidated the function of FhARID1 in citrus apomixis and axillary bud development,providing a fundamental basis for understanding the role of ARID-HMG-related genes.展开更多
Given that the citrus psyllid is the primary vector of citrus Huanglongbing(HLB),there is an urgent need to control this pest to mitigate the spread of the disease.This paper reviews the current research on two predom...Given that the citrus psyllid is the primary vector of citrus Huanglongbing(HLB),there is an urgent need to control this pest to mitigate the spread of the disease.This paper reviews the current research on two predominant control strategies:chemical control and biological control agents,in managing the citrus psyllid.It emphasizes the mechanisms of action,efficacy,and application advancements of these control methods.Finally,the paper analyzes the principal challenges associated with the sustainable management of citrus psyllids and offers perspectives for future research.展开更多
Magnesium(Mg)defciency is becoming a limiting factor for citrus production in acid soils of subtropical and tropical zones.It is speculated that soil Mg leaching and thereby its imbalance may be a major cause of yield...Magnesium(Mg)defciency is becoming a limiting factor for citrus production in acid soils of subtropical and tropical zones.It is speculated that soil Mg leaching and thereby its imbalance may be a major cause of yield decline,yet Mg defciency in citrus receives little attention.A two-year feld experiment was therefore conducted to quantify soil Mg leaching in a typical citrus orchard in China fertilized with varying levels of Mg(Mg0,no Mg fertilizer;Mg45,45 kg MgO ha^(-1)yr^(-1);Mg90,90 kg MgO ha^(-1)yr^(-1);Mg180,180 kg MgO ha^(-1)yr^(-1)).Results showed that Mg application signifcantly increased citrus fruit yield by 4.1-16.4%compared with where MgO was not added.The average amount of soil Mg leaching was 65.7 kg ha^(-1)yr^(-1)where no Mg fertilizer was added,while it reached up to 91.3 kg Mg ha^(-1)yr^(-1)where MgO was added at the rate of 180 kg ha^(-1).Over the 4 treatments,Mg leaching accounted for 12.1-42.4%of the applied Mg fertilizer.Mg leaching and its removal through harvested fruits resulted in an orchard soil Mg balance of-69.9,-51.1,-27.4 and 10.9 kg ha^(-1)in the Mg0,Mg45,Mg90and Mg180,treatments,respectively.The pH values of leachate from the acid soil were alkaline and it contained higher amounts of calcium and potassium than that of Mg.Considering the high leaching of Mg from the acid soils of citrus orchards,applications of Mg fertilizer or Mg-fortifed soil conditioner are vital to sustain soil Mg balance,high fruit yield and fruit quality in citrus production systems in humid subtropical regions.展开更多
Citric acid is an important contributor to fruit flavor.The extremely significant differences in citric acid levels are observed among citrus species and varieties.The molecular basis of citric acid accumulation remai...Citric acid is an important contributor to fruit flavor.The extremely significant differences in citric acid levels are observed among citrus species and varieties.The molecular basis of citric acid accumulation remains largely unknown on the inter-species level.Here,we performed transcriptome analysis of five pairs of acidic and acidless variety fruits from kumquat(Citrus crassifolia),lemon(C.limon),pummelo(C.maxima),mandarin(C.reticulata),and sweet orange(C.sinensis)to investigate the common and specific genes related to citric acid accumulation in these citrus species.Transcript profiles of the citrate metabolism genes revealed that the mechanism of citric acid accumulation in kumquat differed from that in the other four species.The comparative analysis and weighted gene co-expression network analysis identified 61 candidate genes from lemon,pummelo,mandarin,and sweet orange.Vacuolar acidification regulated by CitPH4-CitAN1-CitPH5was a common mechanism underlying citric acid accumulation in these four species.In addition,gene network analysis indicated that CitPH4 was a central regulator,exhibiting a strong correlation with the genes involved in vacuolar trafficking and potassium(K^(+))transport.The co-expression and functional enrichment analyses showed that active sugar metabolism and increased citrate synthesis were mainly responsible for the accumulation of citric acid in kumquat.Twenty-four transcription factors were identified as candidate regulators,of which CitbHLH28 was found to regulate acidity level via transactivating CWINV2 and PK3 expressions.Overall,this study provides an insight into the mechanism of citric acid accumulation in citrus fruit and provides useful references for fruit quality improvement through acidity control in different citrus species.展开更多
Citrus,which has been consumed internationally for a long time,is widely used as a health food.Citrus and its active components exert significant effects on oxidative stress and lipid metabolism,which are closely asso...Citrus,which has been consumed internationally for a long time,is widely used as a health food.Citrus and its active components exert significant effects on oxidative stress and lipid metabolism,which are closely associated with female reproductive health.Studies suggest that citrus-derived compounds may alleviate oxidative stress by activating signaling pathways such as nuclear factor erythroid 2-related factor 2(Nrf2)and Sirtuin 1(SIRT1),and improve lipid metabolism through the activation of pathways such as peroxisome proliferator-activated receptorα(PPARα).This review focuses on the effects of Citrus on oxidative stress and lipid metabolism,aiming to provide new insights for promoting female reproductive health;however,further work is needed to elucidate the mechanisms involved and validate the therapeutic potential of Citrus’s bioactive components in clinical settings.展开更多
Citrus is an important commercial crop in Uganda, especially the Eastern region. However, in spite of the increasing regional demand, citrus productivity is still low, attributed to pest and diseases, soil moisture st...Citrus is an important commercial crop in Uganda, especially the Eastern region. However, in spite of the increasing regional demand, citrus productivity is still low, attributed to pest and diseases, soil moisture stress, and low soil fertility, among others. Efforts to improve soil fertility are limited by inadequate supply of organic fertilizers due to competing demands. In addition, there is inadequate information on inorganic fertilizer requirements for citrus production in Uganda. The objective of this study was to develop optimum fertilizer recommendations for citrus production for Eastern Uganda. The study was conducted in Teso region, Eastern Uganda. Fertilizer (NPK, 17:17:17) was randomly applied to Hamlin, Valencia and Washington varieties with fertilizer and variety factorially arranged for each farm and citrus age range, replicated three times. Fertilizer rates were 0, 139, 278 and 556 kg NPK/ha for the 4 - 7-year old trees, and 0, 278, 556 and 1111 kg NPK/ha for the mature (8 years and above) trees. For a given variety, each fertilizer rate was applied onto three representative trees per farmer, six farmers per district. Results showed that yields and net profits were highest for variety Hamlin, and nearly the same for varieties Washington and Valencia. Fertilizer application increased fruit yield and profits for both the 4 to 7-year and 8 and above-year-old trees, with highest yield and profitability values observed at 556 kg NPK/ha. These results suggest applying 556 kg NPK/ha to citrus per year as an optimum fertilizer rate for citrus production in Teso region. The fertilizer should be applied in smaller splits of 800, 600, and 600 grams per tree, applied in April, June, and August.展开更多
Background During the transition period,excessive negative energy balance(NEB)lead to metabolic disorders and reduced milk yield.Rumen microbes are responsible for resolving plant material and producing volatile fatty...Background During the transition period,excessive negative energy balance(NEB)lead to metabolic disorders and reduced milk yield.Rumen microbes are responsible for resolving plant material and producing volatile fatty acids(VFA),which are the primary energy source for cows.In this study,we aimed to investigate the effect of citrus peel extract(CPE)supplementation on rumen microbiota composition,energy metabolism and milk performance of peri-partum dairy cows.Methods Dairy cows were fed either a basal diet(CON group)or the same basal diet supplemented with CPE via intragastric administration(4 g/d,CPE group)for 6 weeks(3 weeks before and 3 weeks after calving;n=15 per group).Samples of serum,milk,rumen fluid,adipose tissue,and liver were collected to assess the effects of CPE on rumen microbiota composition,rumen fermentation parameters,milk performance,and energy metabolic status of dairy cows.Results CPE supplementation led to an increase in milk yield,milk protein and lactose contents,and serum glucose levels,while reduced serum concentrations of non-esterified fatty acid,β-hydroxybutyric acid,insulin,aspartate aminotransferase,alanine aminotransferase,and haptoglobin during the first month of lactation.CPE supplemen-tation also increased the content of ruminal VFA.Compared to the CON group,the abundance of Prevotellaceae,Methanobacteriaceae,Bacteroidales_RF16_group,and Selenomonadaceae was found increased,while the abun-dance of Oscillospiraceae,F082,Ruminococcaceae,Christensenellaceae,Muribaculaceae UCG-011,Saccharimona-daceae,Hungateiclostridiaceae,and Spirochaetaceae in the CPE group was found decreased.In adipose tissue,CPE supplementation decreased lipolysis,and inflammatory response,while increased insulin sensitivity.In the liver,CPE supplementation decreased lipid accumulation,increased insulin sensitivity,and upregulated expression of genes involved in gluconeogenesis.Conclusions Our findings suggest that CPE supplementation during the peripartum period altered rumen micro-biota composition and increased ruminal VFA contents,which further improved NEB and lactation performance,alleviated lipolysis and inflammatory response in adipose tissue,reduced lipid accumulation and promoted gluconeo-genesis in liver.Thus,CPE might contribute to improve energy metabolism and consequently lactation performance of dairy cows during the transition period.展开更多
The CRISPR/Cas9 system has shown great promise in engineering targeted mutations in a genome.The efficiency of Cas9-mediated genome editing is temperature sensitive.A high-temperature regime can increase the mutation ...The CRISPR/Cas9 system has shown great promise in engineering targeted mutations in a genome.The efficiency of Cas9-mediated genome editing is temperature sensitive.A high-temperature regime can increase the mutation efficiency induced by the CRISPR/Cas9 system in many plant species.However,a heat stress treatment has not been applied during the tissue culture process in citrus.To develop an efficient heat stress regime to improve the efficiency of CRISPR/Cas9-mediated targeted mutagenesis,three and five cycles of heat stress treatments were used during callus induction in citrus.The results showed that the heat stress treatment with three cycles of 24 h at 37℃,followed by 24 h at 26℃,increased the mutation efficiency by 11.6%compared with no heat stress treatment,and that five cycles of heat stress treatment were optimal,from which 50%mutants had a 100%mutation rate.The mutation profiles of Cas9 at 28℃ for 10 d and 37℃ for three or five cycles were similar,indicating that heat stress treatment did not affect the non-homologous end joining repair pathway.No detectable off-target mutation was detected in the potential off-target sites with four nucleotide mismatches compared with the designed on-target site.This study demonstrated that five cycles of heat stress treatment during callus induction could efficiently increase the mutation efficiency mediated by the CRISPR/Cas9 system without observable negative effects,and provided an efficient Cas9-mediated citrus genome editing system to produce mutants with a high mutation rate.展开更多
Chemotherapy-induced toxicity(CIT)remains a major concern in cancer patients undergoing chemotherapy.New approaches to ameliorate the side effects of chemotherapy are urgently needed.Recently,the nutritional value of ...Chemotherapy-induced toxicity(CIT)remains a major concern in cancer patients undergoing chemotherapy.New approaches to ameliorate the side effects of chemotherapy are urgently needed.Recently,the nutritional value of citrus fruits has attracted wide attention.Hesperidin and its aglycone hesperetin are the main active components in citrus fruits.Hesperidin and hesperetin have a wide range of pharmacological activities,including antioxidant and anti-inflammatory properties.This review aims to provide insights into the potential application of citrus flavonoids in CIT and summarize the underlying mechanisms of hesperidin and hesperetin in alleviating CIT.We have collected and collated relevant scientific articles on hesperidin and hesperetin and their treatment of CIT from different scientific databases.Hesperidin and its glycosides can reduce the toxicity of chemotherapeutic drugs,and their therapeutic effects are mainly through anti-inflammatory and antioxidant effects.At present,modern medical treatment is the main treatment method for CIT,but hesperidin,as an extract of food and medicinal materials,can greatly alleviate CIT.While killing tumor cells,chemotherapeutic drugs also damage normal cells leading to toxic effect on various organs.The pathological mechanism of CIT has not been fully elucidated,but current evidences indicate that cellular stress plays a key role.The citrus flavonoids hesperidin and hesperetin have the protective effect against CIT,highlighting its potential as an adjuvant in chemotherapy regimens.Hesperidin may also have synergistic anti-tumor activity with chemotherapeutic agents.We believe that more functional foods and anti-CIT drugs based on natural foods will be developed.展开更多
[Objectives]To select the virus-free Citrus reticulata Hongmeiren as test material to select rootstocks suitable for local cultivation,and to carry out demonstration and popularization of suitable rootstocks for plant...[Objectives]To select the virus-free Citrus reticulata Hongmeiren as test material to select rootstocks suitable for local cultivation,and to carry out demonstration and popularization of suitable rootstocks for planting C.reticulata Hongmeiren in the south bank of Hangzhou Bay.[Methods]The effects of different rootstocks on the survival rate,biological characteristics and fruit quality were analyzed by grafting onto three kinds of rootstocks,namely,C.unshiu Marc.cv.Owari,S.mandarin cv.Miyagawa wase and C.trifoliata L.[Results]The grafting survival rate for C.trifoliata L.was the highest;from the index of scion growth,the scion diameter,new shoot length,new shoot thickness and leaf area of C.unshiu Marc.cv.Owari were the largest,and the tree height of S.mandarin cv.Miyagawa wase was the highest;from the fruit quality index,the fruit quality of C.unshiu Marc.cv.Owari was the best.[Conclusions]C.unshiu Marc.cv.Owari is suitable as the preferred rootstock for virus-free C.reticulata Hongmeiren on the south bank of Hangzhou Bay,and can be demonstrated and promoted.展开更多
Citrus bacterial canker(CBC) is resulted from Xanthomonas citri subsp. citri(Xcc) infection and poses a significant threat to citrus production.Glutathione S-transferases(GSTs) are critical in maintaining redox homeos...Citrus bacterial canker(CBC) is resulted from Xanthomonas citri subsp. citri(Xcc) infection and poses a significant threat to citrus production.Glutathione S-transferases(GSTs) are critical in maintaining redox homeostasis in plants, especially in relation to abiotic and biotic stress responses. However, the function of GSTs in resisting CBC remains unclear. Here, citrus glutathione S-transferases were investigated applying a genome-wide approach. In total, 69 CsGSTs belonging to seven classes were identified, and the phylogeny, chromosomal distribution, gene structures and conserved motifs were analyzed. Several CsGSTs responded to Xcc infection, as observed in the upregulation of CsGSTF1 and CsGSTU18 in the CBC-sensitive ‘Wanjincheng' variety but not in the resistant ‘Kumquat' variety. CsGSTF1 and CsGSTU18 were localized at the cytoplasm. Transient overexpression of CsGSTF1 and CsGSTU18 mediated reactive oxygen species(ROS) scavenging, whereas the virus-induced gene silencing(VIGS) of CsGSTF1 and CsGSTU18 caused strong CBC resistance and ROS burst. The present study investigated the characterization of citrus GST gene family, and discovered that CsGSTF1 and CsGSTU18 negatively contributed to CBC through modulating ROS homeostasis. These findings emphasize the significance of GSTs in infection resistance in plants.展开更多
Pre-harvest water deficit(PHWD)plays an important role in sugar accumulation of citrus fruit.However,the mechanism is not known well.Here,it was confirmed that PHWD promoted sucrose accumulation of citrus fruit,but ha...Pre-harvest water deficit(PHWD)plays an important role in sugar accumulation of citrus fruit.However,the mechanism is not known well.Here,it was confirmed that PHWD promoted sucrose accumulation of citrus fruit,but had limited effect on fructose,glucose and total acid.A sucrose transporter,Cs SUT1,which localizes to the plasma membrane,was demonstrated to function in sucrose transport induced by PHWD.Compared to wild-type,Cs SUT1 overexpression in citrus calli stimulated sucrose,fructose and glucose accumulation,while its silencing in juice sacs reduced sucrose accumulation.Increased sugar accumulation in transgenic lines enhanced plant drought tolerance,and resulted in decreased electrolyte leakage,malondialdehyde and hydrogen peroxide contents,as well as increased superoxide dismutase activity and proline contents.An abscisic acid(ABA)-responsive transcription factor,Cs ABF3,was found with a same expression pattern with Cs SUT1 under PHWD.Yeast one-hybrid,electrophoretic mobility shift assay and dual-luciferase assays all revealed that Cs ABF3 directly bound with the Cs SUT1 promoter by ABA responsive elements.When Cs ABF3 was overexpressed in citrus calli,the sucrose,fructose and glucose concentration increased correspondingly.Further,transgenic studies demonstrated that Cs ABF3 could affect sucrose accumulation by regulating Cs SUT1.Overall,this study revealed a regulation of Cs ABF3 promoting Cs SUT1 expression and sucrose accumulation in response to PHWD.Our results provide a detail insight into the quality formation of citrus fruit.展开更多
[Objectives]The paper was to ascertain the prevalence of diseases and pests in a range of citrus nurseries situated in Guangdong Province and its neighboring provinces.[Methods]Citrus diseases and pests were systemati...[Objectives]The paper was to ascertain the prevalence of diseases and pests in a range of citrus nurseries situated in Guangdong Province and its neighboring provinces.[Methods]Citrus diseases and pests were systematically investigated,and citrus leaf samples were randomly collected from 15 citrus nurseries across 8 regions in Guangdong Province and its neighboring provinces.Quantitative polymerase chain reaction(qPCR)and reverse transcription polymerase chain reaction(RT-PCR)techniques were employed to detect diseases in the collected samples.Additionally,root and substrate samples were obtained,and root-knot nematodes were isolated using the Baermann funnel method.[Results]The positive detection rate of citrus huanglongbing(HLB)was recorded at 3%,indicating an increase in attention towards this disease compared to 2013.Additionally,the positive detection rate for citrus bacterial canker disease(CBCD)was found to be 16.5%.It was observed that the majority of nurseries with positive samples employed open field rearing practices without the use of mesh chambers,and the primary source of scions was self-propagation.The detection rate of citrus tristeza virus(CTV)was found to be the highest,with a positive detection rate of 63%,and the prevalence in disease-bearing nurseries reached as high as 90%.In comparison to 2013,there had been no improvement in the condition of seedlings affected by CTV.The positive detection rate of citrus yellow vein clearing virus(CYVCV)was found to be 38%,with 70%of the surveyed nurseries exhibiting the disease.The citrus varieties identified as carriers of the disease included‘Qicheng’,‘Shatangju’,‘Wogan’,and‘Gonggan’.Nematodes were isolated from the matrix and roots of seedlings grown in both container and open field environments.The susceptibility of container seedlings to nematodes was found to be 36.4%,while the susceptibility of open field seedlings was 38.6%.Statistical analysis indicated no significant difference in susceptibility between the two groups.[Conclusions]The disease detection rates associated with various seedling rearing methods and citrus varieties exhibited notable variability.Open field seedlings without the protection of mesh chambers demonstrated a higher susceptibility to disease.Additionally,the types of infectious diseases varied among the different citrus varieties.展开更多
Hesperidin is a dihydroflavonoids, accounting for more than 50% of the total flavonoids in Citri Reticulatae Pericarpium(CRP) of traditional Chinese medicine. It is an effective antioxidant and free radical scavenger ...Hesperidin is a dihydroflavonoids, accounting for more than 50% of the total flavonoids in Citri Reticulatae Pericarpium(CRP) of traditional Chinese medicine. It is an effective antioxidant and free radical scavenger that has anti-inflammatory, antiviral and hypoglycemic properties.The latest studies reported that hesperidin has a potential for novel coronavirus resistance. However, little is known about the synthesis regulation and accumulation site of hesperidin in plants. In this study, hesperidin synthase gene Crc1,6RhaT was cloned, and the protein can be completely transformed flavanone-7-O-glucoside into hesperidin in vitro and in vivo. Studies on biological characteristics of ovary walls and exocarps showed that the relative expression levels of the Crc1,6RhaT gene and protein decreased gradually with the development of citrus fruits, and the relative content of hesperidin firstly increased, then sequentially decreased. In situ hybridization results further revealed that Crc1,6RhaT transcription was mainly concentrated in the secretory cavity cells, which are revealed to be the site of flavonoid synthesis.Immunocytochemistry localization results showed that the Crc1,6RhaT was mainly located in the endoplasmic reticulum, nucleus and vacuole of secretory cells. We inferred that the Crc1,6RhaT was synthesized in the endoplasmic reticulum, then was transported into the vacuoles through enlarged vesicles at the end of the endoplasmic reticulum. Our results not only revealed that Crc1,6RhaT may be involved in the synthesis of hesperidin of the main bioactive substance in the medicinal plant Citrus reticulata ‘Chachi' fruit, but also provided novel insights into the main subcellular sites of hesperidin biosynthesis in vacuoles.展开更多
Glycation of proteins and DNA forms advanced glycation end products(AGEs)causing cell and tissue dysfunction and subsequent various chronic diseases,in particular,metabolic and age-related diseases.Targeted AGE inhibi...Glycation of proteins and DNA forms advanced glycation end products(AGEs)causing cell and tissue dysfunction and subsequent various chronic diseases,in particular,metabolic and age-related diseases.Targeted AGE inhibition includes scavengers of reactive carbonyl species(RCS)such as methylglyoxal(MG),glyoxalase-1 enhancers,Nrf2/ARE pathway activators,AGE/RAGE formation inhibitors and other antiglycatng agents.Citrus flavonoids have demonstrated antioxidant and anti-inflammatory effects and are also found to be effective antiglycating agents.Herein,we reviewed the up to date progress of the antiglycation effects of citrus flavonoids and associated mechanisms.Major citrus flavonoids,hesperedin and its aglycone,hesperetin,inhibited glycation by scavenging MG forming mono-or di-flavonoid adducts with MG,enhanced the activity of glyoxase-1,activated Akt/Nrf2 signal pathway while inhibiting AGE/RAGE/NF-κB pathway,reduced the formation of Nε-(carboxylmethyl)lysine(CML)and pentosidine,inhibited aldol reductase activity and decreased the levels of fructosamine.The antiglycating activity and mechanisms of other flavonoids was also summarized in this review.In conclusion,citrus flavonoids possess effective antiglycating activity via different mechanisms,yet there are many challenging questions remaining to be studied in the near future such as in vivo testing and human study of citrus flavonoids for efficacy,effectiveness and adverse effects of citrus flavonoids as a functional food in managing high levels of AGEs and controlling AGE-induced chronic diseases,diabetic complications in particular.展开更多
Citrus is the typical mycorrhizal fruit tree species establishing symbiosis with arbuscular mycorrhizal (AM) fungi. However, arbuscule development and senescence in colonized citrus roots, especially in response to dr...Citrus is the typical mycorrhizal fruit tree species establishing symbiosis with arbuscular mycorrhizal (AM) fungi. However, arbuscule development and senescence in colonized citrus roots, especially in response to drought stress, remain unclear, which is mainly due to the difficulty in clearing and staining lignified roots with the conventional method. Here, we improved the observation of colonized roots of citrus plants with the sectioning method, which enabled the clear observation of AM fungal structures. Furthermore, we investigated the effects of one week of drought stress on arbuscule development and senescence with the sectioning method. Microscopy observations indicated that drought stress significantly decreased mycorrhizal colonization (F%and M%) although it did not affect plant growth performance. Fluorescence probes (WGA 488 and/or Nile red) revealed that drought stress inhibited arbuscule development by increasing the percentage of arbuscules at the early stage and decreasing the percentages of arbuscules at the midterm and mature stages. Meanwhile, drought stress accelerated arbuscule senescence, which was characterized by the increased accumulation of neutral lipids. Overall, the sectioning method developed in this study enables the in-depth investigation of arbuscule status, and drought stress can inhibit arbuscule development but accelerate arbuscule senescence in the colonized roots of citrus plants. This study paves the way to elaborately dissecting the arbuscule dynamics in the roots of fruit tree species in response to diverse abiotic stresses.展开更多
Citrus yellow vein clearing virus(CYVCV)is a new citrus virus that has become an important factor restricting the development of China’s citrus industry,and the CYVCV coat protein(CP)is associated with viral pathogen...Citrus yellow vein clearing virus(CYVCV)is a new citrus virus that has become an important factor restricting the development of China’s citrus industry,and the CYVCV coat protein(CP)is associated with viral pathogenicity.In this study,the Eureka lemon zinc finger protein(ZFP)ClDOF3.4 was shown to interact with CYVCV CP in vivo and in vitro.Transient expression of ClDOF3.4 in Eureka lemon induced the expression of salicylic acid(SA)-related and hypersensitive response marker genes,and triggered a reactive oxygen species burst,ion leakage necrosis,and the accumulation of free SA.Furthermore,the CYVCV titer in ClDOF3.4 transgenic Eureka lemon plants was approximately 69.4%that in control plants 6 mon after inoculation,with only mild leaf chlorotic spots observed in those transgenic plants.Taken together,the results indicate that ClDOF3.4 not only interacts with CP but also induces an immune response in Eureka lemon by inducing the SA pathways.This is the first report that ZFP is involved in the immune response of a citrus viral disease,which provides a basis for further study of the molecular mechanism of CYVCV infection.展开更多
文摘A devastating disease called Huanglongbing(HLB) or citrus green is wiping out citrus trees across the globe. But we are seeing new hope. Scientists have recently uncovered a hidden battle happening inside citrus plants. Understanding this microscopic tug-of-war could be the key to rescuing our beloved oranges, lemons, and grapefruits.
基金supported by the National Natural Science Foundation of China(31971424)。
文摘Asian citrus psyllid(ACP)is a significant pest of citrus crops that can transmit citrus Huanglongbing(HLB)by feeding on the phloem sap of citrus plants,which poses a significant threat to citrus production.Volatile signal chemicals with plant communication functions can effectively enhance the resistance of recipient plants to herbivorous insects with minimal impacts on plant growth.While(E)-4,8-dimethyl-1,3,7-nonatriene(DMNT),(E,E)-4,8,12-trimethyl-1,3,7,11-tridecene(TMTT),(E)-β-caryophyllene,and dimethyl disulfide(DMDS),are known as signaling molecules in guava-sweet orange communication,whether these four chemical signals can enhance the resistance of Citrus sinensis to feeding by ACP adults with no apparent costs in terms of plant growth remains unclear.Therefore,this study measured the effect of non-damaging induction by DMNT,TMTT,(E)-β-caryophyllene,and DMDS on the ability of C.sinensis to resist feeding by ACP,as well as their impacts on the defensive phytochemicals,defensive enzymes,functional nutrients,Photosystem II's utilization and allocation of light energy,photosynthetic pigments,growth conditions,and leaf stomatal aperture in C.sinensis.The results indicate that non-damaging induction by these four chemicals can enhance the activity of the defensive enzyme polyphenol oxidase(PPO)and increase the contents of total phenols,tannins,and terpenoid defensive phytochemicals within C.sinensis,thereby enhancing the resistance of C.sinensis to ACP feeding.Specifically,DMNT and DMDS exhibit more significant effects in inducing resistance compared to TMTT and(E)-β-caryophyllene.The characteristics of chlorophyll fluorescence parameters and changes in photosynthetic pigments in C.sinensis during different post-exposure induction periods revealed these chemicals can maintain the stability of the photosynthetic system in C.sinensis and regulate its capacity to capture,transmit,and distribute light energy,which significantly enhances the non-photochemical quenching ability of C.sinensis.In addition,detailed measurements of the water content,leaf mass per unit area(LMA),functional nutrients(soluble protein,soluble sugar,and amino acids),and stomatal parameters in C.sinensis leaves further indicated that the non-destructive induction by these chemicals can optimize the levels of functional nutrients in C.sinensis,primarily manifesting as the upregulation of soluble sugars,proline,or soluble proteins,and reduction of stomatal area and aperture,which maintains a stable leaf water content and LMA,thereby enhancing resistance to ACP while sustaining the healthy growth of C.sinensis.These results fully substantiate that the non-damaging induction by the signal chemicals DMNT,TMTT,(E)-β-caryophyllene,and DMDS can enhance the resistance of C.sinensis to ACP feeding while maintaining the balance between pest resistance and growth.This balance prevents any catastrophic effects on the growth of C.sinensis,so these agents can potentially be integrated with other pest management strategies for the collective protection of crops.This study provides theoretical support and assistance for the development of signal chemical inducers for the prevention and management of ACP in agricultural systems.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(Grant Nos.LQ23C150004 and LR23C150001)National Natural Science Foundation of China(NSFC+1 种基金Grant No.32102318)NSFC Excellent Young Scientists Fund,and the Key Project for New Agricultural Cultivar Breeding in Zhejiang Province,China(Grant No.2021C02066-1).
文摘Chlorophyll degradation and carotenoid accumulation are essential processes of fruit maturation in many horticultural plants,and play a crucial role in fruit color and quality.The pathways of chlorophyll and carotenoid biosynthesis and degradation are well understood,and key regulatory genes controlling these pathways have been identified in citrus.This article reviewed the recent research on chlorophyll and carotenoid metabolism in citrus fruits,encompassing the metabolic pathways,transcriptional regulation,influencing factors,and the interplay between chlorophyll and carotenoid metabolism,aiming to provide insights into the molecular regulatory mechanisms governing the coloration of citrus fruits.
基金funded by the National Key Research and Development Program of China(Grant No.2022YFF1003100)Modern Citrus Industry Technology System of China(Grant No.CARS-26).
文摘Polyembryony has posed a significant impediment to the advancement of citrus hybrid breeding.FhRWP is widely regarded as a pivotal factor governing asexual reproduction in citrus,and prior research has demonstrated that FhARID1,acting as an upstream regulator,modulates FhRWP expression.In this study,we performed a genome-wide characterization of the ARID-HMG-related genes using the short juvenile minicitrus Fortunella hindsii.A total of 20 ARID-HMG-related genes were identified.Protein interaction network and enrichment analysis suggested that ARID-HMG-related proteins might might be involved in chromatin remodeling complexes.Knockout of FhARID1 in F.hindsii did not induce the conversion from polyembryony to monoembryony.However,fharid1 plants in T1 generation exhibited abnormal proliferation at axillary buds,which is similar to phenotype of fhrwp plants.Expression analysis of fharid1 ovary tissues revealed the downregulation of FhRWP.The results indicated that FhARID1,as an upstream regulator of FhRWP,has an effect on the development of citrus axillary buds.Expression analysis of overexpressed leaves of FhARID1 lines showed that no significant up-regulation of FhRWP,indicating that FhARID1 is not the sole upstream regulatory factor of FhRWP.Only FhARID2 showed a correlation in expression with FhARID1 among the ARID-related genes,further supporting the notion that this gene may be involved in complex formation rather than acting alone.Yeast two-hybrid and MS/MS spectra further indicated that FhARID1 function requires casein kinase II-mediated post-transcriptional phosphorylation.This study elucidated the function of FhARID1 in citrus apomixis and axillary bud development,providing a fundamental basis for understanding the role of ARID-HMG-related genes.
基金Supported by National Undergraduate Training Programs for Innovation and Entrepreneurship(202510580009)Special Project for Promoting the Coordinated Development of Urban and Rural Areas and Regions by Introducing Scientific and Technological Achievements of Guangdong Province into Counties and Towns(2025B0202010051)Project of High-quality Development in Hundred Counties,Thousands Towns and Ten Thousand Villages of Guangdong Provincial Department of Science and Technology:Key Dispatch Project for Rural Science and Technology Commissioners(KTP20240704).
文摘Given that the citrus psyllid is the primary vector of citrus Huanglongbing(HLB),there is an urgent need to control this pest to mitigate the spread of the disease.This paper reviews the current research on two predominant control strategies:chemical control and biological control agents,in managing the citrus psyllid.It emphasizes the mechanisms of action,efficacy,and application advancements of these control methods.Finally,the paper analyzes the principal challenges associated with the sustainable management of citrus psyllids and offers perspectives for future research.
基金supported by the International Magnesium Institute,Fujian Agriculture and Forestry University,Chinathe National Natural Science Foundation of China(32172676)+2 种基金the Danling Science&Technology Backyard Project,China(F2024236)the Dalian Xinmei Project,China(MY01-2023-2025-02)the Sichuan Province Regional Innovation Cooperation Project,China(22QYCX0073)。
文摘Magnesium(Mg)defciency is becoming a limiting factor for citrus production in acid soils of subtropical and tropical zones.It is speculated that soil Mg leaching and thereby its imbalance may be a major cause of yield decline,yet Mg defciency in citrus receives little attention.A two-year feld experiment was therefore conducted to quantify soil Mg leaching in a typical citrus orchard in China fertilized with varying levels of Mg(Mg0,no Mg fertilizer;Mg45,45 kg MgO ha^(-1)yr^(-1);Mg90,90 kg MgO ha^(-1)yr^(-1);Mg180,180 kg MgO ha^(-1)yr^(-1)).Results showed that Mg application signifcantly increased citrus fruit yield by 4.1-16.4%compared with where MgO was not added.The average amount of soil Mg leaching was 65.7 kg ha^(-1)yr^(-1)where no Mg fertilizer was added,while it reached up to 91.3 kg Mg ha^(-1)yr^(-1)where MgO was added at the rate of 180 kg ha^(-1).Over the 4 treatments,Mg leaching accounted for 12.1-42.4%of the applied Mg fertilizer.Mg leaching and its removal through harvested fruits resulted in an orchard soil Mg balance of-69.9,-51.1,-27.4 and 10.9 kg ha^(-1)in the Mg0,Mg45,Mg90and Mg180,treatments,respectively.The pH values of leachate from the acid soil were alkaline and it contained higher amounts of calcium and potassium than that of Mg.Considering the high leaching of Mg from the acid soils of citrus orchards,applications of Mg fertilizer or Mg-fortifed soil conditioner are vital to sustain soil Mg balance,high fruit yield and fruit quality in citrus production systems in humid subtropical regions.
基金financially supported by the National Natural Science Foundation of China(Grant No.31925034)the National Key Research and Development Program of China(Grant No.2022YFF1003100)+1 种基金the Foundation of Hubei Hongshan Laboratory(Grant No.2021hszd016)Key project of Hubei provincial Natural Science Foundation(Grant No.2021CFA017)。
文摘Citric acid is an important contributor to fruit flavor.The extremely significant differences in citric acid levels are observed among citrus species and varieties.The molecular basis of citric acid accumulation remains largely unknown on the inter-species level.Here,we performed transcriptome analysis of five pairs of acidic and acidless variety fruits from kumquat(Citrus crassifolia),lemon(C.limon),pummelo(C.maxima),mandarin(C.reticulata),and sweet orange(C.sinensis)to investigate the common and specific genes related to citric acid accumulation in these citrus species.Transcript profiles of the citrate metabolism genes revealed that the mechanism of citric acid accumulation in kumquat differed from that in the other four species.The comparative analysis and weighted gene co-expression network analysis identified 61 candidate genes from lemon,pummelo,mandarin,and sweet orange.Vacuolar acidification regulated by CitPH4-CitAN1-CitPH5was a common mechanism underlying citric acid accumulation in these four species.In addition,gene network analysis indicated that CitPH4 was a central regulator,exhibiting a strong correlation with the genes involved in vacuolar trafficking and potassium(K^(+))transport.The co-expression and functional enrichment analyses showed that active sugar metabolism and increased citrate synthesis were mainly responsible for the accumulation of citric acid in kumquat.Twenty-four transcription factors were identified as candidate regulators,of which CitbHLH28 was found to regulate acidity level via transactivating CWINV2 and PK3 expressions.Overall,this study provides an insight into the mechanism of citric acid accumulation in citrus fruit and provides useful references for fruit quality improvement through acidity control in different citrus species.
基金supported by the National Natural Science Foundation of China(No.82374510)the General Scientific Research Project of the Education Department of Zhejiang Province(No.Y202455593),China.
文摘Citrus,which has been consumed internationally for a long time,is widely used as a health food.Citrus and its active components exert significant effects on oxidative stress and lipid metabolism,which are closely associated with female reproductive health.Studies suggest that citrus-derived compounds may alleviate oxidative stress by activating signaling pathways such as nuclear factor erythroid 2-related factor 2(Nrf2)and Sirtuin 1(SIRT1),and improve lipid metabolism through the activation of pathways such as peroxisome proliferator-activated receptorα(PPARα).This review focuses on the effects of Citrus on oxidative stress and lipid metabolism,aiming to provide new insights for promoting female reproductive health;however,further work is needed to elucidate the mechanisms involved and validate the therapeutic potential of Citrus’s bioactive components in clinical settings.
文摘Citrus is an important commercial crop in Uganda, especially the Eastern region. However, in spite of the increasing regional demand, citrus productivity is still low, attributed to pest and diseases, soil moisture stress, and low soil fertility, among others. Efforts to improve soil fertility are limited by inadequate supply of organic fertilizers due to competing demands. In addition, there is inadequate information on inorganic fertilizer requirements for citrus production in Uganda. The objective of this study was to develop optimum fertilizer recommendations for citrus production for Eastern Uganda. The study was conducted in Teso region, Eastern Uganda. Fertilizer (NPK, 17:17:17) was randomly applied to Hamlin, Valencia and Washington varieties with fertilizer and variety factorially arranged for each farm and citrus age range, replicated three times. Fertilizer rates were 0, 139, 278 and 556 kg NPK/ha for the 4 - 7-year old trees, and 0, 278, 556 and 1111 kg NPK/ha for the mature (8 years and above) trees. For a given variety, each fertilizer rate was applied onto three representative trees per farmer, six farmers per district. Results showed that yields and net profits were highest for variety Hamlin, and nearly the same for varieties Washington and Valencia. Fertilizer application increased fruit yield and profits for both the 4 to 7-year and 8 and above-year-old trees, with highest yield and profitability values observed at 556 kg NPK/ha. These results suggest applying 556 kg NPK/ha to citrus per year as an optimum fertilizer rate for citrus production in Teso region. The fertilizer should be applied in smaller splits of 800, 600, and 600 grams per tree, applied in April, June, and August.
基金National Key R&D Program of China(Beijing,China,grant no.2023YFE0116900 and 2023YFD1801400)National Natural Science Foundation of China(Beijing,China,grant no.32473105,32302943,and 32302941)Postdoctoral Fellowship Program of CPSF(GZC20230951).
文摘Background During the transition period,excessive negative energy balance(NEB)lead to metabolic disorders and reduced milk yield.Rumen microbes are responsible for resolving plant material and producing volatile fatty acids(VFA),which are the primary energy source for cows.In this study,we aimed to investigate the effect of citrus peel extract(CPE)supplementation on rumen microbiota composition,energy metabolism and milk performance of peri-partum dairy cows.Methods Dairy cows were fed either a basal diet(CON group)or the same basal diet supplemented with CPE via intragastric administration(4 g/d,CPE group)for 6 weeks(3 weeks before and 3 weeks after calving;n=15 per group).Samples of serum,milk,rumen fluid,adipose tissue,and liver were collected to assess the effects of CPE on rumen microbiota composition,rumen fermentation parameters,milk performance,and energy metabolic status of dairy cows.Results CPE supplementation led to an increase in milk yield,milk protein and lactose contents,and serum glucose levels,while reduced serum concentrations of non-esterified fatty acid,β-hydroxybutyric acid,insulin,aspartate aminotransferase,alanine aminotransferase,and haptoglobin during the first month of lactation.CPE supplemen-tation also increased the content of ruminal VFA.Compared to the CON group,the abundance of Prevotellaceae,Methanobacteriaceae,Bacteroidales_RF16_group,and Selenomonadaceae was found increased,while the abun-dance of Oscillospiraceae,F082,Ruminococcaceae,Christensenellaceae,Muribaculaceae UCG-011,Saccharimona-daceae,Hungateiclostridiaceae,and Spirochaetaceae in the CPE group was found decreased.In adipose tissue,CPE supplementation decreased lipolysis,and inflammatory response,while increased insulin sensitivity.In the liver,CPE supplementation decreased lipid accumulation,increased insulin sensitivity,and upregulated expression of genes involved in gluconeogenesis.Conclusions Our findings suggest that CPE supplementation during the peripartum period altered rumen micro-biota composition and increased ruminal VFA contents,which further improved NEB and lactation performance,alleviated lipolysis and inflammatory response in adipose tissue,reduced lipid accumulation and promoted gluconeo-genesis in liver.Thus,CPE might contribute to improve energy metabolism and consequently lactation performance of dairy cows during the transition period.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFD1201600)Earmarked Fund for China Agriculture Research System(Grant No.CARS-26)+1 种基金Chongqing Natural Science Foundation Project(Grant No.CSTB2023NSCQ-MSX1085)Cultivar Improvement of Nanfeng Orange.
文摘The CRISPR/Cas9 system has shown great promise in engineering targeted mutations in a genome.The efficiency of Cas9-mediated genome editing is temperature sensitive.A high-temperature regime can increase the mutation efficiency induced by the CRISPR/Cas9 system in many plant species.However,a heat stress treatment has not been applied during the tissue culture process in citrus.To develop an efficient heat stress regime to improve the efficiency of CRISPR/Cas9-mediated targeted mutagenesis,three and five cycles of heat stress treatments were used during callus induction in citrus.The results showed that the heat stress treatment with three cycles of 24 h at 37℃,followed by 24 h at 26℃,increased the mutation efficiency by 11.6%compared with no heat stress treatment,and that five cycles of heat stress treatment were optimal,from which 50%mutants had a 100%mutation rate.The mutation profiles of Cas9 at 28℃ for 10 d and 37℃ for three or five cycles were similar,indicating that heat stress treatment did not affect the non-homologous end joining repair pathway.No detectable off-target mutation was detected in the potential off-target sites with four nucleotide mismatches compared with the designed on-target site.This study demonstrated that five cycles of heat stress treatment during callus induction could efficiently increase the mutation efficiency mediated by the CRISPR/Cas9 system without observable negative effects,and provided an efficient Cas9-mediated citrus genome editing system to produce mutants with a high mutation rate.
基金Innovative Team Project of Ordinary Universities in Guangdong Province(No.2022KCXTD016).
文摘Chemotherapy-induced toxicity(CIT)remains a major concern in cancer patients undergoing chemotherapy.New approaches to ameliorate the side effects of chemotherapy are urgently needed.Recently,the nutritional value of citrus fruits has attracted wide attention.Hesperidin and its aglycone hesperetin are the main active components in citrus fruits.Hesperidin and hesperetin have a wide range of pharmacological activities,including antioxidant and anti-inflammatory properties.This review aims to provide insights into the potential application of citrus flavonoids in CIT and summarize the underlying mechanisms of hesperidin and hesperetin in alleviating CIT.We have collected and collated relevant scientific articles on hesperidin and hesperetin and their treatment of CIT from different scientific databases.Hesperidin and its glycosides can reduce the toxicity of chemotherapeutic drugs,and their therapeutic effects are mainly through anti-inflammatory and antioxidant effects.At present,modern medical treatment is the main treatment method for CIT,but hesperidin,as an extract of food and medicinal materials,can greatly alleviate CIT.While killing tumor cells,chemotherapeutic drugs also damage normal cells leading to toxic effect on various organs.The pathological mechanism of CIT has not been fully elucidated,but current evidences indicate that cellular stress plays a key role.The citrus flavonoids hesperidin and hesperetin have the protective effect against CIT,highlighting its potential as an adjuvant in chemotherapy regimens.Hesperidin may also have synergistic anti-tumor activity with chemotherapeutic agents.We believe that more functional foods and anti-CIT drugs based on natural foods will be developed.
文摘[Objectives]To select the virus-free Citrus reticulata Hongmeiren as test material to select rootstocks suitable for local cultivation,and to carry out demonstration and popularization of suitable rootstocks for planting C.reticulata Hongmeiren in the south bank of Hangzhou Bay.[Methods]The effects of different rootstocks on the survival rate,biological characteristics and fruit quality were analyzed by grafting onto three kinds of rootstocks,namely,C.unshiu Marc.cv.Owari,S.mandarin cv.Miyagawa wase and C.trifoliata L.[Results]The grafting survival rate for C.trifoliata L.was the highest;from the index of scion growth,the scion diameter,new shoot length,new shoot thickness and leaf area of C.unshiu Marc.cv.Owari were the largest,and the tree height of S.mandarin cv.Miyagawa wase was the highest;from the fruit quality index,the fruit quality of C.unshiu Marc.cv.Owari was the best.[Conclusions]C.unshiu Marc.cv.Owari is suitable as the preferred rootstock for virus-free C.reticulata Hongmeiren on the south bank of Hangzhou Bay,and can be demonstrated and promoted.
基金funded by the National Key Research and Development Program of China (Grant No.2022YFD1201600)Natural Science Foundation of Chongqing (Grant No.cstc2020jcyj-msxmX1064)+1 种基金Earmarked Funds for the China Agriculture Research System (Grant No.CARS-26)Three-year Action Plan of Xi'an University (Grant No.2021XDJH41)。
文摘Citrus bacterial canker(CBC) is resulted from Xanthomonas citri subsp. citri(Xcc) infection and poses a significant threat to citrus production.Glutathione S-transferases(GSTs) are critical in maintaining redox homeostasis in plants, especially in relation to abiotic and biotic stress responses. However, the function of GSTs in resisting CBC remains unclear. Here, citrus glutathione S-transferases were investigated applying a genome-wide approach. In total, 69 CsGSTs belonging to seven classes were identified, and the phylogeny, chromosomal distribution, gene structures and conserved motifs were analyzed. Several CsGSTs responded to Xcc infection, as observed in the upregulation of CsGSTF1 and CsGSTU18 in the CBC-sensitive ‘Wanjincheng' variety but not in the resistant ‘Kumquat' variety. CsGSTF1 and CsGSTU18 were localized at the cytoplasm. Transient overexpression of CsGSTF1 and CsGSTU18 mediated reactive oxygen species(ROS) scavenging, whereas the virus-induced gene silencing(VIGS) of CsGSTF1 and CsGSTU18 caused strong CBC resistance and ROS burst. The present study investigated the characterization of citrus GST gene family, and discovered that CsGSTF1 and CsGSTU18 negatively contributed to CBC through modulating ROS homeostasis. These findings emphasize the significance of GSTs in infection resistance in plants.
基金supported by the National Natural Science Foundation of China(Grant No.32172520)the earmarked fund for China Agriculture Research System(Grant No.CARS-26)。
文摘Pre-harvest water deficit(PHWD)plays an important role in sugar accumulation of citrus fruit.However,the mechanism is not known well.Here,it was confirmed that PHWD promoted sucrose accumulation of citrus fruit,but had limited effect on fructose,glucose and total acid.A sucrose transporter,Cs SUT1,which localizes to the plasma membrane,was demonstrated to function in sucrose transport induced by PHWD.Compared to wild-type,Cs SUT1 overexpression in citrus calli stimulated sucrose,fructose and glucose accumulation,while its silencing in juice sacs reduced sucrose accumulation.Increased sugar accumulation in transgenic lines enhanced plant drought tolerance,and resulted in decreased electrolyte leakage,malondialdehyde and hydrogen peroxide contents,as well as increased superoxide dismutase activity and proline contents.An abscisic acid(ABA)-responsive transcription factor,Cs ABF3,was found with a same expression pattern with Cs SUT1 under PHWD.Yeast one-hybrid,electrophoretic mobility shift assay and dual-luciferase assays all revealed that Cs ABF3 directly bound with the Cs SUT1 promoter by ABA responsive elements.When Cs ABF3 was overexpressed in citrus calli,the sucrose,fructose and glucose concentration increased correspondingly.Further,transgenic studies demonstrated that Cs ABF3 could affect sucrose accumulation by regulating Cs SUT1.Overall,this study revealed a regulation of Cs ABF3 promoting Cs SUT1 expression and sucrose accumulation in response to PHWD.Our results provide a detail insight into the quality formation of citrus fruit.
基金Supported by Earmarked Fund for China Agriculture Research System(CARS-26)Science and Technology Innovation Guidance Project of Zhaoqing City(2023040308008)+1 种基金Undergraduate Innovation and Entrepreneurship Training Program of Guangdong Province(S202310580050)Project of High-quality Development in Hundred Counties,Thousands Towns and Ten Thousand Villages.
文摘[Objectives]The paper was to ascertain the prevalence of diseases and pests in a range of citrus nurseries situated in Guangdong Province and its neighboring provinces.[Methods]Citrus diseases and pests were systematically investigated,and citrus leaf samples were randomly collected from 15 citrus nurseries across 8 regions in Guangdong Province and its neighboring provinces.Quantitative polymerase chain reaction(qPCR)and reverse transcription polymerase chain reaction(RT-PCR)techniques were employed to detect diseases in the collected samples.Additionally,root and substrate samples were obtained,and root-knot nematodes were isolated using the Baermann funnel method.[Results]The positive detection rate of citrus huanglongbing(HLB)was recorded at 3%,indicating an increase in attention towards this disease compared to 2013.Additionally,the positive detection rate for citrus bacterial canker disease(CBCD)was found to be 16.5%.It was observed that the majority of nurseries with positive samples employed open field rearing practices without the use of mesh chambers,and the primary source of scions was self-propagation.The detection rate of citrus tristeza virus(CTV)was found to be the highest,with a positive detection rate of 63%,and the prevalence in disease-bearing nurseries reached as high as 90%.In comparison to 2013,there had been no improvement in the condition of seedlings affected by CTV.The positive detection rate of citrus yellow vein clearing virus(CYVCV)was found to be 38%,with 70%of the surveyed nurseries exhibiting the disease.The citrus varieties identified as carriers of the disease included‘Qicheng’,‘Shatangju’,‘Wogan’,and‘Gonggan’.Nematodes were isolated from the matrix and roots of seedlings grown in both container and open field environments.The susceptibility of container seedlings to nematodes was found to be 36.4%,while the susceptibility of open field seedlings was 38.6%.Statistical analysis indicated no significant difference in susceptibility between the two groups.[Conclusions]The disease detection rates associated with various seedling rearing methods and citrus varieties exhibited notable variability.Open field seedlings without the protection of mesh chambers demonstrated a higher susceptibility to disease.Additionally,the types of infectious diseases varied among the different citrus varieties.
基金supported by the National Natural Science Foundation of China (Grant No.32270381)Natural Science Foundation of Guangdong (Grant No.2022A1515011086)+2 种基金Key Realm R&D Program of Guangdong Province (Grant No.2020B020221001)Provincial Special Fund for Modern Agriculture Industry Technology Innovation Teams (Grant No.2019KJ125)Research Fund of Maoming Branch,Guangdong Laboratory for Lingnan Modern Agriculture (Grant No.2022KF009)。
文摘Hesperidin is a dihydroflavonoids, accounting for more than 50% of the total flavonoids in Citri Reticulatae Pericarpium(CRP) of traditional Chinese medicine. It is an effective antioxidant and free radical scavenger that has anti-inflammatory, antiviral and hypoglycemic properties.The latest studies reported that hesperidin has a potential for novel coronavirus resistance. However, little is known about the synthesis regulation and accumulation site of hesperidin in plants. In this study, hesperidin synthase gene Crc1,6RhaT was cloned, and the protein can be completely transformed flavanone-7-O-glucoside into hesperidin in vitro and in vivo. Studies on biological characteristics of ovary walls and exocarps showed that the relative expression levels of the Crc1,6RhaT gene and protein decreased gradually with the development of citrus fruits, and the relative content of hesperidin firstly increased, then sequentially decreased. In situ hybridization results further revealed that Crc1,6RhaT transcription was mainly concentrated in the secretory cavity cells, which are revealed to be the site of flavonoid synthesis.Immunocytochemistry localization results showed that the Crc1,6RhaT was mainly located in the endoplasmic reticulum, nucleus and vacuole of secretory cells. We inferred that the Crc1,6RhaT was synthesized in the endoplasmic reticulum, then was transported into the vacuoles through enlarged vesicles at the end of the endoplasmic reticulum. Our results not only revealed that Crc1,6RhaT may be involved in the synthesis of hesperidin of the main bioactive substance in the medicinal plant Citrus reticulata ‘Chachi' fruit, but also provided novel insights into the main subcellular sites of hesperidin biosynthesis in vacuoles.
基金support from the High Level Scientific Research Cultivation Project of Huanggang Normal University(202108504)from the National Natural Science Foundation of China(31571832)。
文摘Glycation of proteins and DNA forms advanced glycation end products(AGEs)causing cell and tissue dysfunction and subsequent various chronic diseases,in particular,metabolic and age-related diseases.Targeted AGE inhibition includes scavengers of reactive carbonyl species(RCS)such as methylglyoxal(MG),glyoxalase-1 enhancers,Nrf2/ARE pathway activators,AGE/RAGE formation inhibitors and other antiglycatng agents.Citrus flavonoids have demonstrated antioxidant and anti-inflammatory effects and are also found to be effective antiglycating agents.Herein,we reviewed the up to date progress of the antiglycation effects of citrus flavonoids and associated mechanisms.Major citrus flavonoids,hesperedin and its aglycone,hesperetin,inhibited glycation by scavenging MG forming mono-or di-flavonoid adducts with MG,enhanced the activity of glyoxase-1,activated Akt/Nrf2 signal pathway while inhibiting AGE/RAGE/NF-κB pathway,reduced the formation of Nε-(carboxylmethyl)lysine(CML)and pentosidine,inhibited aldol reductase activity and decreased the levels of fructosamine.The antiglycating activity and mechanisms of other flavonoids was also summarized in this review.In conclusion,citrus flavonoids possess effective antiglycating activity via different mechanisms,yet there are many challenging questions remaining to be studied in the near future such as in vivo testing and human study of citrus flavonoids for efficacy,effectiveness and adverse effects of citrus flavonoids as a functional food in managing high levels of AGEs and controlling AGE-induced chronic diseases,diabetic complications in particular.
基金supported by grants from the Natural Science Foundation of China (Grant No.42077040)the open competition program of top ten critical priorities of Agricultural Science and Technology Innovation for the 14th Five-Year Plan of Guangdong Province (Grant Nos.2022SDZG09,2023SDZG09)+1 种基金the Natural Science Foundation of Guangdong (Grant No.2021B1515010868)the GDAS Project of Science and Technology Development(2021GDASYL-20210103023)。
文摘Citrus is the typical mycorrhizal fruit tree species establishing symbiosis with arbuscular mycorrhizal (AM) fungi. However, arbuscule development and senescence in colonized citrus roots, especially in response to drought stress, remain unclear, which is mainly due to the difficulty in clearing and staining lignified roots with the conventional method. Here, we improved the observation of colonized roots of citrus plants with the sectioning method, which enabled the clear observation of AM fungal structures. Furthermore, we investigated the effects of one week of drought stress on arbuscule development and senescence with the sectioning method. Microscopy observations indicated that drought stress significantly decreased mycorrhizal colonization (F%and M%) although it did not affect plant growth performance. Fluorescence probes (WGA 488 and/or Nile red) revealed that drought stress inhibited arbuscule development by increasing the percentage of arbuscules at the early stage and decreasing the percentages of arbuscules at the midterm and mature stages. Meanwhile, drought stress accelerated arbuscule senescence, which was characterized by the increased accumulation of neutral lipids. Overall, the sectioning method developed in this study enables the in-depth investigation of arbuscule status, and drought stress can inhibit arbuscule development but accelerate arbuscule senescence in the colonized roots of citrus plants. This study paves the way to elaborately dissecting the arbuscule dynamics in the roots of fruit tree species in response to diverse abiotic stresses.
基金supported by the China Agriculture Research System of MOF and MARA(CARS26-05B)the Innovation Research 2035 Pilot Plan of Southwest University,China(SWU-XDPY22002)+1 种基金the Guangxi Science and Technology Planed Project,China(Gui Ke AD23026090)the Guangxi Natural Science Foundation,China(2023GXNSFBA026285).
文摘Citrus yellow vein clearing virus(CYVCV)is a new citrus virus that has become an important factor restricting the development of China’s citrus industry,and the CYVCV coat protein(CP)is associated with viral pathogenicity.In this study,the Eureka lemon zinc finger protein(ZFP)ClDOF3.4 was shown to interact with CYVCV CP in vivo and in vitro.Transient expression of ClDOF3.4 in Eureka lemon induced the expression of salicylic acid(SA)-related and hypersensitive response marker genes,and triggered a reactive oxygen species burst,ion leakage necrosis,and the accumulation of free SA.Furthermore,the CYVCV titer in ClDOF3.4 transgenic Eureka lemon plants was approximately 69.4%that in control plants 6 mon after inoculation,with only mild leaf chlorotic spots observed in those transgenic plants.Taken together,the results indicate that ClDOF3.4 not only interacts with CP but also induces an immune response in Eureka lemon by inducing the SA pathways.This is the first report that ZFP is involved in the immune response of a citrus viral disease,which provides a basis for further study of the molecular mechanism of CYVCV infection.
