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
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
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
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
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
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
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
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
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 pH plays a key role in the growth and colonization of plant pathogens as well as the onset and progression of the symptoms they cause within the host.Plants may quickly alter their apoplastic pH(pH_(apo))to protec...The pH plays a key role in the growth and colonization of plant pathogens as well as the onset and progression of the symptoms they cause within the host.Plants may quickly alter their apoplastic pH(pH_(apo))to protect themselves against infection.However,pathogens can also alter the pH of their ambient environment to promote their own growth.Citrus canker is a serious plant disease caused by Xanthomonas citri subsp.citri(Xcc).This Gram-negative aerobic rod is usually cultured in LuriaeBertani(LB)medium at pH 7.However,little is known about the changes in pH both in this medium as Xcc grows and in the leaf apoplast in response to Xcc infection and colonization.Moreover,the differences in leaf apoplast pH between Xcc-resistant and Xcc-susceptible citrus genotypes are also unknown.Here,Xcc grew well in liquid LB medium at initial pH 6e8 and the pathogen altered the medium pH to 6.8±0.4.Xcc growth declined at pH 5 and was zero at pH 3,4,9,and 10.In susceptible sweet orange infected with Xcc inoculum,canker symptoms were inhibited at pH 3,4,and 10 but did not differ in the range of pH 5e9.As expected,canker symptoms were absent at all inoculum pH in the resistant Citron C-05.For both genotypes,Xcc only grew well in the leaves exposed to pH 5e8 inoculums.At four days post-inoculation(4 dpi),the foliar pH_(apo) of resistant Citron C-05 had rapidly declined from 5.6 to 4.4.At 2 dpi,the pH_(apo) of susceptible sweet orange had rapidly increased from 5.6 to 6.7,Xcc grew quickly,and canker symptoms appeared.Plasma membrane(PM)Ht-ATPase activation with fusicoccin(FC)acidified the apoplast and upregulated the pathogenesis-related genes(PRs)in the sweet orange leaves.Hence,Xcc colonization and canker development were inhibited.The results of this study revealed that apoplastic acidification is implicated in the resistance of Citron C-05 to Xcc infection and provided insight into the association between pH_(apo) regulation and resistance to bacterial pathogen invasion in plants.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
Citrus canker,caused by Xanthomonas citri subsp.citri(Xcc),is a globally quarantine disease infecting nearly all Citrus cultivars.Citron C-05 has been identified with complete and active resistance to Xcc.However,the ...Citrus canker,caused by Xanthomonas citri subsp.citri(Xcc),is a globally quarantine disease infecting nearly all Citrus cultivars.Citron C-05 has been identified with complete and active resistance to Xcc.However,the mechanism underlying Citron C-05's resistance to Xcc remains elusive.We identified a gene cluster on chromosome 8 of the citrus genome comprising five pathogenesis-related 4-like genes.PR4A was upregulated in Citron C-05 leaves under Xcc infection,exhibiting the highest expression among these PR4-like genes.In addition,PR4A expression was higher in leaves of disease-resistant genotypes than susceptible genotypes under Xcc invasion.Bimolecular fluorescence complementation(BiFC)and Split-Luc assays indicated that CmWRKY75,a positive regulator of PR4A,interacted with pthA4 and upregulated expression of PR4A in Citron C-05 leaves.Regulatory function for the expression of CmPR4A was localized to a 516-nucleotide region upstream of the translational start site,which was designated Pro CmPR4A-P516.Transient overexpression of CmPR4A improved resistance to Xcc in sweet orange,and three transgenic lines of OE-CmPR4A exhibited resistance to Pseudomonas syringae pv.tomato DC3000(Pst DC3000)in Arabidopsis.Furthermore,CmSMU2 was identified through yeast two-hybrid library using CmPR4A as bait,Bi FC and Split-Luc assays further verified their interaction.Transient overexpression of CmSMU2 in sweet orange increased resistance to Xcc.Co-expression of CmSMU2 and CmPR4A enhanced accumulation of reactive oxygen species compared to CmSMU2 or CmPR4A,indicating that they may synergistically enhance resistance to Xcc in citrus.These findings lay the groundwork for a theoretical analysis of the mechanism underlying the resistance of Citron C-05 against citrus canker.展开更多
[Objective] The aim was to observe the antibacterial effect of nano-scale Titanium dioxide on parasitic bacterium of Nanfeng Citrus in storage period.[Method] Nano-scale Titanium dioxide was prepared by dibutyl phthal...[Objective] The aim was to observe the antibacterial effect of nano-scale Titanium dioxide on parasitic bacterium of Nanfeng Citrus in storage period.[Method] Nano-scale Titanium dioxide was prepared by dibutyl phthalate through sol-gel method under anhydrous conditions,and orthogonal experiment was used to determine optimum conditions for nano-scale Titanium dioxide preparation,and structure characterization of nano-scale Titanium dioxide was carried out by X-Ray diffractometer.Oxford cup method was used to explore inhibition effect of nano-scale Titanium dioxide suspension on the activity of normal parasitic bacterium of Nanfeng Citrus.Simultaneously,the empirical preservation test was carried out.[Result] The average diameter of nano-scale Titanium dioxide powder attained to 14.6 nm,actual average yield could reach 90.83% with RSD（Relative Standard Deviation）of 0.86%.[Conclusion] Nano-scale Titanium dioxide had good antibacterial effect on the parasitic bacterium of Nanfeng Citrus in storage period.展开更多
[Objective] This study aimed to optimize the SCoT-PCR system for Citrus.Under the optimized SCoT-PCR amplification conditions, the genetic DNA of Youzishatangju and Wuzishatangju were amplified. [Method] Orthogonal de...[Objective] This study aimed to optimize the SCoT-PCR system for Citrus.Under the optimized SCoT-PCR amplification conditions, the genetic DNA of Youzishatangju and Wuzishatangju were amplified. [Method] Orthogonal design was adopted to optimize the five influencing factors on amplification effect of SCoT-PCR,including the DNA template, Mg2＋, primers, dNTPs and Taq DNA polymerse concentrations. With the optimized SCoT-PCR system, the genomic DNA of Youzishatangju and Wuzishatangju were amplified by 60 SCoT primers, respectively, and the specific bands for Youzishatangju or Wuzishatangju were selected for SCAR transformation. [Result] The optimized SCoT-PCR reaction system（20 μl） was as follows： Mg2＋1.5 mmol/L, d NTPs 0.35 mmol/L, primer 0.25 μmol/L, Taq enzyme 0.5 U, DNA template 30 ng. The optimum annealing temperature was 50.6 °C. With the optimized SCoT-PCR system, the genomic DNA of Youzishatangju and Wuzishatangju were amplified respectively by 60 SCoT primers, and a total of 42 pairs of primers were screened. Among the 42 pairs of primers, only one primer amplified different band pattern between Youzishatangju and Wuzishatangju. [Conclusion] It indicates that there is certain difference between Youzishatangju and Wuzishatangju at genomic DNA level.展开更多
Leaf-derived protoplasts of Rough lemon (Citrus jambhiri Lush, 2n = 2x = 18) were electrofused with embryogenic suspension protoplasts of its relative, Microcitrus papuana Swingle (2n = 2x = 18), with an intention of ...Leaf-derived protoplasts of Rough lemon (Citrus jambhiri Lush, 2n = 2x = 18) were electrofused with embryogenic suspension protoplasts of its relative, Microcitrus papuana Swingle (2n = 2x = 18), with an intention of creating novel germplasm. Six plants were regenerated following protoplasts fusion. Cytological examination demonstrated that they were diploids with 18 chromosomes (2n = 2x = 18). RAPD (random amplified polymorphic DNA) analyses with six arbitrary 10-mer primers showed that the regenerated plants had identical band patterns to those of Rough lemon for primers OPA-07, OPAN-07, OPE-05 and OPA-08, Whereas for the other two primers, OPA-04 and OPS-13, bands specific to M. papuana could be detected in the regenerated plants. Cytological and RAPD analysis revealed that the regenerated plants were diploid somatic hybrids between M. papuana and Rough lemon. The putative hybrids were morphologically similar to Rough lemon. This is the first report on production of diploid somatic hybrid plants between citrus with its related genus via symmetric fusion.展开更多
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.
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.
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 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.
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 grants from the Provincial Special Project of the Research and Demonstration of High-Efficiency Breeding Technology for Citrus,China(Grant No.2024sfq02)Postgraduate Scientific Research Innovation Project of Hunan Province,China(Grant No.CX20210671).
文摘The pH plays a key role in the growth and colonization of plant pathogens as well as the onset and progression of the symptoms they cause within the host.Plants may quickly alter their apoplastic pH(pH_(apo))to protect themselves against infection.However,pathogens can also alter the pH of their ambient environment to promote their own growth.Citrus canker is a serious plant disease caused by Xanthomonas citri subsp.citri(Xcc).This Gram-negative aerobic rod is usually cultured in LuriaeBertani(LB)medium at pH 7.However,little is known about the changes in pH both in this medium as Xcc grows and in the leaf apoplast in response to Xcc infection and colonization.Moreover,the differences in leaf apoplast pH between Xcc-resistant and Xcc-susceptible citrus genotypes are also unknown.Here,Xcc grew well in liquid LB medium at initial pH 6e8 and the pathogen altered the medium pH to 6.8±0.4.Xcc growth declined at pH 5 and was zero at pH 3,4,9,and 10.In susceptible sweet orange infected with Xcc inoculum,canker symptoms were inhibited at pH 3,4,and 10 but did not differ in the range of pH 5e9.As expected,canker symptoms were absent at all inoculum pH in the resistant Citron C-05.For both genotypes,Xcc only grew well in the leaves exposed to pH 5e8 inoculums.At four days post-inoculation(4 dpi),the foliar pH_(apo) of resistant Citron C-05 had rapidly declined from 5.6 to 4.4.At 2 dpi,the pH_(apo) of susceptible sweet orange had rapidly increased from 5.6 to 6.7,Xcc grew quickly,and canker symptoms appeared.Plasma membrane(PM)Ht-ATPase activation with fusicoccin(FC)acidified the apoplast and upregulated the pathogenesis-related genes(PRs)in the sweet orange leaves.Hence,Xcc colonization and canker development were inhibited.The results of this study revealed that apoplastic acidification is implicated in the resistance of Citron C-05 to Xcc infection and provided insight into the association between pH_(apo) regulation and resistance to bacterial pathogen invasion in plants.
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supported by the National Natural Science Foundation of China(32402500 and 31741110)the Scientific Research Fund of Hunan Provincial Education Department,China(21B0220)。
文摘Citrus canker,caused by Xanthomonas citri subsp.citri(Xcc),is a globally quarantine disease infecting nearly all Citrus cultivars.Citron C-05 has been identified with complete and active resistance to Xcc.However,the mechanism underlying Citron C-05's resistance to Xcc remains elusive.We identified a gene cluster on chromosome 8 of the citrus genome comprising five pathogenesis-related 4-like genes.PR4A was upregulated in Citron C-05 leaves under Xcc infection,exhibiting the highest expression among these PR4-like genes.In addition,PR4A expression was higher in leaves of disease-resistant genotypes than susceptible genotypes under Xcc invasion.Bimolecular fluorescence complementation(BiFC)and Split-Luc assays indicated that CmWRKY75,a positive regulator of PR4A,interacted with pthA4 and upregulated expression of PR4A in Citron C-05 leaves.Regulatory function for the expression of CmPR4A was localized to a 516-nucleotide region upstream of the translational start site,which was designated Pro CmPR4A-P516.Transient overexpression of CmPR4A improved resistance to Xcc in sweet orange,and three transgenic lines of OE-CmPR4A exhibited resistance to Pseudomonas syringae pv.tomato DC3000(Pst DC3000)in Arabidopsis.Furthermore,CmSMU2 was identified through yeast two-hybrid library using CmPR4A as bait,Bi FC and Split-Luc assays further verified their interaction.Transient overexpression of CmSMU2 in sweet orange increased resistance to Xcc.Co-expression of CmSMU2 and CmPR4A enhanced accumulation of reactive oxygen species compared to CmSMU2 or CmPR4A,indicating that they may synergistically enhance resistance to Xcc in citrus.These findings lay the groundwork for a theoretical analysis of the mechanism underlying the resistance of Citron C-05 against citrus canker.
文摘[Objective] The aim was to observe the antibacterial effect of nano-scale Titanium dioxide on parasitic bacterium of Nanfeng Citrus in storage period.[Method] Nano-scale Titanium dioxide was prepared by dibutyl phthalate through sol-gel method under anhydrous conditions,and orthogonal experiment was used to determine optimum conditions for nano-scale Titanium dioxide preparation,and structure characterization of nano-scale Titanium dioxide was carried out by X-Ray diffractometer.Oxford cup method was used to explore inhibition effect of nano-scale Titanium dioxide suspension on the activity of normal parasitic bacterium of Nanfeng Citrus.Simultaneously,the empirical preservation test was carried out.[Result] The average diameter of nano-scale Titanium dioxide powder attained to 14.6 nm,actual average yield could reach 90.83% with RSD（Relative Standard Deviation）of 0.86%.[Conclusion] Nano-scale Titanium dioxide had good antibacterial effect on the parasitic bacterium of Nanfeng Citrus in storage period.
基金Supported by Foundation for Distinguished Young Talents in Higher Education of Guangdong,China(2012LM0135)Scientific and Technological Innovation Project of Zhaoqing City,Guangdong Province(2012G21)Guangdong Provincial Natural Science Foundation(S2013010015195)~~
文摘[Objective] This study aimed to optimize the SCoT-PCR system for Citrus.Under the optimized SCoT-PCR amplification conditions, the genetic DNA of Youzishatangju and Wuzishatangju were amplified. [Method] Orthogonal design was adopted to optimize the five influencing factors on amplification effect of SCoT-PCR,including the DNA template, Mg2＋, primers, dNTPs and Taq DNA polymerse concentrations. With the optimized SCoT-PCR system, the genomic DNA of Youzishatangju and Wuzishatangju were amplified by 60 SCoT primers, respectively, and the specific bands for Youzishatangju or Wuzishatangju were selected for SCAR transformation. [Result] The optimized SCoT-PCR reaction system（20 μl） was as follows： Mg2＋1.5 mmol/L, d NTPs 0.35 mmol/L, primer 0.25 μmol/L, Taq enzyme 0.5 U, DNA template 30 ng. The optimum annealing temperature was 50.6 °C. With the optimized SCoT-PCR system, the genomic DNA of Youzishatangju and Wuzishatangju were amplified respectively by 60 SCoT primers, and a total of 42 pairs of primers were screened. Among the 42 pairs of primers, only one primer amplified different band pattern between Youzishatangju and Wuzishatangju. [Conclusion] It indicates that there is certain difference between Youzishatangju and Wuzishatangju at genomic DNA level.
文摘Leaf-derived protoplasts of Rough lemon (Citrus jambhiri Lush, 2n = 2x = 18) were electrofused with embryogenic suspension protoplasts of its relative, Microcitrus papuana Swingle (2n = 2x = 18), with an intention of creating novel germplasm. Six plants were regenerated following protoplasts fusion. Cytological examination demonstrated that they were diploids with 18 chromosomes (2n = 2x = 18). RAPD (random amplified polymorphic DNA) analyses with six arbitrary 10-mer primers showed that the regenerated plants had identical band patterns to those of Rough lemon for primers OPA-07, OPAN-07, OPE-05 and OPA-08, Whereas for the other two primers, OPA-04 and OPS-13, bands specific to M. papuana could be detected in the regenerated plants. Cytological and RAPD analysis revealed that the regenerated plants were diploid somatic hybrids between M. papuana and Rough lemon. The putative hybrids were morphologically similar to Rough lemon. This is the first report on production of diploid somatic hybrid plants between citrus with its related genus via symmetric fusion.
