Phosphorus(Pi)plays a crucial role in the growth and development of plants.Membrane lipid regulation is one of the main mechanisms underlying plant adaptation to Pi deficiency.Previously,the high tolerance to low-Pi s...Phosphorus(Pi)plays a crucial role in the growth and development of plants.Membrane lipid regulation is one of the main mechanisms underlying plant adaptation to Pi deficiency.Previously,the high tolerance to low-Pi stress was justified in an elite line,MSDZ 109,which was obtained from Malus mandshurica.To better understand the mechanism underlying high adaptation to low-Pi stress,currently,lipidomic and transcriptomic analysis,as well as CRISPR/Cas9 and MmGDPD1-overexpressing methodologies were comprehensively integrated into a strategy for elucidating the high tolerance to low-Pi stress.Totally,770 differential metabolites were identified from the roots between the low-Pi and stress-free,belonging to 21 sub-classes of lipid compounds.Fatty acids(FA)constituted the predominant lipid component,accounting for approximately 50%-60%of the total lipids,and triglycerides(TAG)ranked the second,comprising around 12%of the total,consecutively followed by phosphatidylcholine(PC)and diacylglycerol(DAG)with approximately 10%and 8%of the total,respectively.The synchronous transcriptomic analysis revealed a significant up-regulation of genes related to glycerophospholipid and glycerolipid metabolism,specifically those(e.g.,MmGDPD1,MmDGDG1,MmMGDG1,MmSQDG,etc.)involved in phospholipid and galactosyl synthesis in response to low-Pi stress.GUS fusing reporter assay showed that MmGDPD1 promoter induced GUS gene expression and demonstrated initiation activity.Based on expression analysis,a dual-luciferase reporter assay,as well as yeast one-hybrid(Y1H)identification,MmPHR1 was justified to bind with the MmGDPD1 promoter and positively regulate plant tolerance to low-Pi stress.To further elucidate the role of MmGDPD1,CRISPR/Cas9 and MmGDPD1-overexpressing vectors were successfully introduced into apple(‘Royal Gala')calli.Interestingly,the MmGDPD1-KO line calli exhibited the remarkable decreases in the contents of phosphodiesterase(PDE),activity,as well as the contents of total Pi,and Pi in comparison with those of the wild type.Conversely,MmGDPD1-OE ones demonstrated the significant elevation in Pi accumulations,further justifying its potential role in Pi remobilization in apple.Therefore,MmGDPD1 substantially involves elevating low-Pi tolerance via promoting Pi release in M.mandshurica.展开更多
The use of a stable reference gene is fundamental for achieving reliable quantitative qRT-PCR (qPCR) results. Developing and evaluating the stability of reference genes is necessary for studying the molecular mechanis...The use of a stable reference gene is fundamental for achieving reliable quantitative qRT-PCR (qPCR) results. Developing and evaluating the stability of reference genes is necessary for studying the molecular mechanisms of M. transitoria in response to drought stress. In this study, 18 candidate reference genes were selected from transcriptome sequencing data of M. transitoria according to their FPKM values under different drought stress degrees. Cluster-23533.34641 was identified as the most stable reference gene for M. transitoria under drought stress based on qPCR results and combined analysis of Genorm, NormFinder, BestKeeper, and Delta Ct algorithms. The reference genes identified in this research offer improved accuracy for quantifying target gene expression in both M. transitoria and Malus species under drought stress. This study could provide insights into the drought stress-related functional gene or factor in M. transitoria, even in Malus species.展开更多
This study aimed to decipher the mechanism by which exogenous methyl jasmonate(MeJA)regulated the photosynthesis of Malus spectabilis leaves under ozone(O_(3))stress.The photosynthetic parameters and chlorophyll fluor...This study aimed to decipher the mechanism by which exogenous methyl jasmonate(MeJA)regulated the photosynthesis of Malus spectabilis leaves under ozone(O_(3))stress.The photosynthetic parameters and chlorophyll fluorescence parameters of M.spectabilis‘Hongjiu’seedlings under O_(3)stress were measured by spraying different concentrations of MeJA.The results showed that O_(3)stress significantly reduced the chlorophyll a and total chlorophyll content,net photosynthetic rate(Pn),stomatal conductance(G_(s)),transpiration rate(T_(r)),maximum fluorescence yield(F_(m)),maximum quantum yield of photosystem II(F_(v)/F_(m)),and actual photochemical efficiency of photosystem II(Ф_(PSII)),while increasing the intercellular CO_(2)concentration(Ci).Exogenous MeJA reduced the Ci and original fluorescence yield(Fo),while increasing chlorophyll a,chlorophyll b,and total chlorophyll content,P_(n),G_(s),T_(r),F_(m),F_(v)/F_(m),andФ_(PSII) of the leaves under O_(3)stress.The application of 150μmol/L MeJA showed the best effect.The above results demonstrated that exogenous MeJA could enhance chlorophyll content and photosynthetic capacity,thereby improving the tolerance of M.spectabilis to O_(3)stress.展开更多
By pot experiment under artificially simulated water stress conditions, soluble protein content, MDA content and SOD, POD, CAT and APX activities in Malus sieversfi leaves were determined to reveal the response mechan...By pot experiment under artificially simulated water stress conditions, soluble protein content, MDA content and SOD, POD, CAT and APX activities in Malus sieversfi leaves were determined to reveal the response mechanism of M. sieversii to changes of relative soil water content. According to the results, with the decrease of relative soil water content, MDA content in M. sieversii leaves increased by mem- brane lipid peroxidation. Cells resist water stress-induced membrane lipid peroxidation and clear the increased reactive oxygen species by improving soluble protein content and SOD, POD, CAT and APX activities. However, various enzymes were involved in the response to water stress under different moisture conditions. In addition, the results indicated that M. sieversii had a good adaptability to higher relative soil water contents.展开更多
Malus sieversii, a wild progenitor of domesticated apple, is distributed in western Xinjiang of China, eastern part of Kazakhstan and Kyrgyzstan in Central Asia. To well understand the genetic structure and the his- t...Malus sieversii, a wild progenitor of domesticated apple, is distributed in western Xinjiang of China, eastern part of Kazakhstan and Kyrgyzstan in Central Asia. To well understand the genetic structure and the his- torical demography of this important germplasm resource, we sampled 15 populations with 110 individuals of Malus sieversii from the Yili Valley and the western mountains of the Junggar Basin, Xinjiang, and sequenced two nrDNA fragments for these 110 individuals. Meanwhile, we modeled and compared species distributions under the current and the Last Glacial Maximum climatic conditions. The results showed that populations of M. sieversfi from Xinjiang had low levels of genetic diversity and genetic differentiation. During the LGM period, populations of M. sieversfi had lost their northern distributions in the western mountains of the Junggar Basin. M. sieversfi has ex- perienced a demographic expansion from the south of the Yili Valley to the north of the western mountains of the Junggar Basin during the warm interglacial epochs. Due to the high sensibility of M. sieversii to disturbance, we proposed more attention should be paid to the M. sieversfi populations in the western mountains of the Junggar Basin.展开更多
Plant growth-promoting rhizobacteria(PGPR) located in rhizobacteria soil are beneficial to plant growth and development. A PGPR strain AMCC100017 of Brevibacillus laterosporus synthesizes the plant hormone IAA in a tr...Plant growth-promoting rhizobacteria(PGPR) located in rhizobacteria soil are beneficial to plant growth and development. A PGPR strain AMCC100017 of Brevibacillus laterosporus synthesizes the plant hormone IAA in a tryptophan-dependent manner. In this study, the AMCC100017 strain was used to treat Malus robusta, an excellent natural rootstock for apple production, and assess its ability to promote growth. The fresh weight, dry weight, plant height, and lateral root growth of M. robusta were significantly increased with treatment. The presence of the AMCC100017 strain increased IAA content in M. robusta and promoted root secretion of tryptophan. Colonization of the strain in the roots allowed continuous synthesis of IAA and promoted plant growth. In addition, the photosynthetic efficiency in leaves increased after microbial treatment, and the utilization of nitrogen, zinc, iron, copper and magnesium in leaves was increased, which was conducive to photosynthesis.Interestingly, the activities of CAT and SOD, as well as the contents of ROS in plants colonized by AMCC100017 were increased compared to control plants, but the activities of POD and MDA contents were decreased. AMCC100017 strain affected the antioxidant capacity and stress resistance of plants. AMCC100017 strain increased the content of soluble protein and soluble sugar in plants, improved plant metabolic activity and stress resistance. Therefore, AMCC100017 not only increased IAA content and photosynthetic efficiency to promote M. robusta growth, but also affected plant through multiple metabolic pathways.展开更多
What the researchers go in for is to establish models between root architecture （RA） changes and nutrition, mold ideal root architecture of apple trees, improve the nutrient uptake efficiency, and further explore th...What the researchers go in for is to establish models between root architecture （RA） changes and nutrition, mold ideal root architecture of apple trees, improve the nutrient uptake efficiency, and further explore the functional mechanism of nutrient elements during the course of RA construction. The cultivation system of filter paper is utilized to research the effect of nutrient deficiency on the RA of Malus hupehensis （Pamp.） Rehd. There may be eight types of RA. In complete Hogland solution, the main type of RA is ＂lateral roots clustering in the upper and middle regions of primary root＂. With the lack of P, K or Ca, the main type of RA is ＂lateral roots clustering in the upper region primary root＂, and the ＂lateral roots clustering in the upper and middle regions of primary root＂ types of RA decrease. But with shortage of P, the type of lateral roots clustering in the upper and lower regions of primary root increases, and the type of lateral roots clustering in the middle region of primary root decreases, with the types of RA diversified. Under the condition of K deficiency, the type of no lateral root increases and types of lateral roots clustering in the middle region of primary root decrease, and the percentage of such types as ＂no lateral root＂, ＂lateral roots clustering in the upper region of primary root＂, and ＂lateral roots clustering in the upper and middle regions of primary root＂ accounts for 97.9% in all, with the types of RA simplified. With lack of Fe, Mg or Zn, the main type of RA is ＂lateral roots clustering in the upper and middle regions of primary root＂, but the type of lateral roots evenly-distributed on primary root increases. The main type of RA is ＂lateral roots evenlydistributed on primary root＂, under the condition of N deficiency, and the types of RA turn out to be diversified. There exists a close relation between nutrient deficiency and RA changes. Owing to various forms of nutrient deficiency, correspondingly different types of RA have been produced.展开更多
This paper studied the effects of cinnamon acid treatments on the respiratory rate and related enzymes activity in the seedling roots of Malus hupehensis Rehd.It would provide information for understanding the mechani...This paper studied the effects of cinnamon acid treatments on the respiratory rate and related enzymes activity in the seedling roots of Malus hupehensis Rehd.It would provide information for understanding the mechanisms of inhibition damage caused by continuous cultivation of apple tree.20 mL of solution containing different concentrations of cinnamon acid was added into container with the tested seedlings.After treatment,the samples were taken periodically and the respiratory rates were measured by OXY-LAB oxygen electrodes under 25°C stable temperature and then the activities of related enzymes were measured.The rates of total respiration and other 2 pathways [tricarboxylic acid cycle （TCA） and pentose phosphate pathway （PPP）] appeared initially an increasing treads and late （on the 3rd d） began to decline.However,they again appeared an increase trend at the end period,on the contrast,the respiratory rate of embden-meyer- hot-parnas （EMP） pathway appeared a stead decline tread but it had a recover on the last day.The respiratory rate of total and 3 pathways were decreased under 125 mg kg-1 （soil）.The dynamic trends of the enzymes activities of pyrophosphate-dependent phosphofructokinase （PFK）,glucose-6-phosphate dehydrogenase （G-6-PDH） and malate dehydrogenase （MDH） showed similarly.In conclusion,treatments of certain concentration of cinnamon acid would inhibit the respiratory rate and related enzymes activity of roots of M.hupehensis Rehd.And the inhibition degrees were positively related with concentration of cinnamon acid treatments.展开更多
Volatile compounds from the ripened crabapple fruit of six varieties （Red Splendor, Strawberry Parfait, Pink Spire, Radiant, Sparkler, and Flame） were analyzed by the use of the SPME/GC/MS method. The changes in the...Volatile compounds from the ripened crabapple fruit of six varieties （Red Splendor, Strawberry Parfait, Pink Spire, Radiant, Sparkler, and Flame） were analyzed by the use of the SPME/GC/MS method. The changes in the volatiles between the ripened and upon full maturity fruit states were studied in Red Splendor and Strawberry Parfait. An effort was made to summarize an effective method for searching and identifying new idioplasms containing a particular fruit aroma within Malus. A total of 37 compounds were identified from the sample. The main aroma volatiles of the six varieties of fruit were comprised of 2-hexenal, 3-hexenal, hexanal, 2,4-hexadienal, benzaldehyde, diethyl phtbalate. The main volatile compound of the crabapple fruit was 2-hexenal, but the relative content percentages were different （45.37, 21.98, 33.56, 32.21, 38.60, and 45.88%）. The aroma components accumulated differently as the fruits ripened. The relative content of aldehydes and esters decreased as alcohols increased after the Red Splendor and Strawberry Parfait fruit ripened. For Red Splendor, the main volatile was still 2-hexenal, but the relative content decreased to 42.89%, and the relative content of alcohols increased by 13.86% as aldehydes and esters declined by 12.16 and 7.18%, respectively. For Strawberry Parfait, the main volatile was changed to cyclohexanol, and the relative content increased to 46.43%, while the relative content of alcohols increased by 49.03% as aldehydes and esters declined by 23.74 and 9.34%, respectively.展开更多
China is a center of diversity for Malus Mill,with 27 native species including 21 wild species and six domesticated species.We applied a set of 19 simple sequence repeat markers to genotype 798 accessions of 17 specie...China is a center of diversity for Malus Mill,with 27 native species including 21 wild species and six domesticated species.We applied a set of 19 simple sequence repeat markers to genotype 798 accessions of 17 species(12 wild species and five cultivated species)of Malus originating from 14 provinces in China.A total of 500 alleles were detected.Diversity statistics indicated a high level of genetic variation as quantified by the average values of the effective allele number(N_(e)).expected heterozygosity(H_(e)),and Shannon's Information Index(I)(10.309,0.886,and 2.545,respectively).Malus sieversii(MSR;H_(e)=0.814,I=2.041,N_(e)=6.054),M.baccata(MBB;H_(e)=0.848,/=2.350,N_(e)=8.652),M.toringoides(MTH;He=0.663,I=1.355,N_(e)=3.332),and M.hupehensis(MHR;H_(e)=0.539,I=0.912,N_(e)=0.579)showed a higher level of genetic diversity in this study than the previous studies.MSR and MBB contributed to the origin and evolution of some accessions of M.domestica subsp.chinensis(MDC).However,other accessions of MDC showed a closer genetic distance with MBB and cultivated species,especially M.robusta(MRB),M.asiatica(MAN),and M.prunifolia(MPB).Not all accessions of MDC were descended from MSR in Xinjiang Uygur Autonomous Region of China.This research provides novel insights into the genetic relationships of Malus native to China,which will be useful for genetic association studies,germplasm conservation,and breeding programs.展开更多
Dopamine plays numerous physiological roles in plants.We explored its role in the regulation of growth,nutrient absorption,and response to nitrogen(N)deficiency in Malus hupehensis Rehd.Under low N condition,plant gro...Dopamine plays numerous physiological roles in plants.We explored its role in the regulation of growth,nutrient absorption,and response to nitrogen(N)deficiency in Malus hupehensis Rehd.Under low N condition,plant growth slowed,and the net photosynthetic rates,chlorophyll contents,and maximal quantum yield of PSII(Fv/Fm)decreased significantly.However,the application of 100μmol L−1 exogenous dopamine significantly reduced the inhibition of low N stress on plant growth.In addition to modifying root system architecture under low N supply,exogenous dopamine also changed the uptake,transport,and distribution of N,P,and K.Furthermore,exogenous dopamine enhances the tolerance to low nitrogen stress by increasing the activity of enzymes(nitrate reductase,nitrite reductase,glutamic acid synthase and glutamine synthetase)involved in N metabolism.We also found that exogenous dopamine promoted the expression of ethylene signaling genes(ERF1,ERF2,EIL1,ERS2,ETR1,and EIN4)under low N stress.Therefore,we hypothesized that ethylene might be involved in dopamine response to low N stress in M.hupehensis.Our results suggest that exogenous dopamine can mitigate low N stress by regulating the absorption of mineral nutrients,possibly through the regulation of the ethylene signaling pathway.展开更多
Water deficit is one of the main limiting factors for apple growth and production.Root architecture plays an important role in drought tolerance of plants.However,little is known about the molecular basis of root syst...Water deficit is one of the main limiting factors for apple growth and production.Root architecture plays an important role in drought tolerance of plants.However,little is known about the molecular basis of root system in apple trees under drought.In this study,we compared root morphology of two widely used rootstocks of apple(R3 and Malus sieversii)under drought.Our results suggested that M.sieversii is more tolerant to drought than R3,since M.sieversii had a higher ratio of root to shoot as well as root hydraulic conductivity under long-term drought conditions.We then performed whole-genome transcriptomic analysis to figure out the molecular basis of root responses in M.sieversii under drought.It was found that genes involved in transcription regulation,signaling or biosynthesis of hormones,and oxidative stress were differentially expressed under drought.Consistent with the gene expression profile,roots of M.sieversii had higher activities of peroxidase(POD)and superoxide dismutase(SOD)under drought,as well as higher content of abscisic acid(ABA)and lower content of auxin.Taken together,our results revealed the physiological and transcriptomic analyses of M.sieversii roots in response to drought.展开更多
The method for constructing core collection ofMalus sieversii based on molecular marker data was proposed. According to 128 SSR allele of 109 M. sieversii, an allele preferred sampling strategy was used to construct M...The method for constructing core collection ofMalus sieversii based on molecular marker data was proposed. According to 128 SSR allele of 109 M. sieversii, an allele preferred sampling strategy was used to construct M. sieversii core collection, using the UPGMA （unweighted pair-group average method） cluster method according to Nei ＆ Li, SM, and Jaccard genetic distances, by stepwise clustering, and compared with the random sampling strategy. The number of lost allele and t-test of Nei＇s gene diversity and Shannon＇s information index were used to evaluate the representative core collections. The results showed that compared with the random sampling strategy, allele preferred sampling strategy could construct more representative core collections. SM, difference for construction of M. sieversii core collection. Jaccard, and Nei ＆ Li genetic distances had no significant SRAP （sequence-related amplified polymorphism） data and morphological data showed that allele preferred sampling strategy was a good sampling strategy for constructing core collection of M. sieversii. Allele preferred sampling strategy combined with SM, Jaccard, and Nei ＆ Li genetic distances using stepwise clustering was the suitable method for constructing M. sieversii core collection.展开更多
Apple bot canker [Botryosphaeria dothidea（Moug.） Ces.et de Not.] is distributed worldwide,resulting in a serious crop loss every year in apple（Malus domestica Borkh.） production.The resistance of each seedling der...Apple bot canker [Botryosphaeria dothidea（Moug.） Ces.et de Not.] is distributed worldwide,resulting in a serious crop loss every year in apple（Malus domestica Borkh.） production.The resistance of each seedling derived from a hybrid population（Jonathan×Golden Delicious） was evaluated by disease index either from natural infection in the field or from inoculation with five isolates of B.dothidea,Ls1,Lw023,Lw048,Mx1,and Zz26.The inheritance of the resistance to bot canker was analyzed via frequency distribution analysis,and microsatellite and AFLP markers linked to the resistance loci were screened.From the binary frequency distribution patterns,it was found that the segregation ratio of resistant/susceptible genotypes infected by pathogen isolates Lw023 and Ls1 was 1：15;and that by Zz26 and Mx1 was 15：1.The variation of resistance was involved in the segregation of two to four alleles of major genes,the resistance was recessive when infected by Lw023 and Ls1,but was dominant when infected with Mx1 and Zz26.A microsatellite maker,CH02a04-450,and two AFLP markers,E-AG/M-GAC-280 and E-AGG/M-CTT-110,were identified,and their map distances to the resistance loci were 5.1,5.1 and 6.2 cM,respectively.The three markers are located in different linkage groups,while CH02a04-450 is on linkage group 2 or 7.E-AG/M-GAC-280 was successfully converted into SCAR159.Finally,CH02a04-450 and SCAR159 were re-examined in inoculated segregation population and presented a good reliability on predicting phenotypes of resistance.展开更多
The free putrescine （Put） content, the hydrogen peroxide （H202） content and the polyamine oxidase （PAO） activity in roots of Malus hupehensis Rehd. var. pinyiensis Jiang （PYTC） were significantly increased, an...The free putrescine （Put） content, the hydrogen peroxide （H202） content and the polyamine oxidase （PAO） activity in roots of Malus hupehensis Rehd. var. pinyiensis Jiang （PYTC） were significantly increased, and reached its peak at 1, 2 and 6 h, respectively, under cadmium treatment. The free spermine （Spin） and spermidine （Spd） contents were dramatically decreased, and reached the minimum value at 4-6 h, then remained relatively stable. The change in total free polyammes （PAs） content was consistent with that of free Put. The number of root dead cells was gradually increased after treatment for 24 h, and the typical characteristics of programmed cell death （PCD） were displayed at 48 h. Throughout the Cd treatment process, changes in PAs metabolism appeared to be prior to cell death increase, and the H2O2 content was always maintained at a high level. These results indicated that polyamines could initiate cell death by generating H2O2 in roots of Malus hupehensis Rehd. under CdSO4 stress.展开更多
Dopamine is a catecholamine and an anti-oxidant which functions in responses to stress and it interacts with plant hormones to mediate plant development.At present,there are few studies on the functions of dopamine in...Dopamine is a catecholamine and an anti-oxidant which functions in responses to stress and it interacts with plant hormones to mediate plant development.At present,there are few studies on the functions of dopamine in apple.This study developed a method for dopamine determination which was used to analyze dopamine in Malus germplasm,in order to clarify the tissue distribution,developmental changes,diurnal variations,and stress responses in apple trees.First,the proposed method was verified.The linear range of quantification was robust from 0.1 to 20 ng mL^(–1).The instrumental,inter-day precision,and sample repeatability relative standard deviations were 1.024,5.607,and 7.237%,respectively.The spiked recovery was greater than 100%,indicating the feasibility of the method and its suitability for the rapid analysis of dopamine in Malus.Next,the dopamine content was measured in 322 Malus tissues.The results showed that the dopamine level in Malus was low and the average dopamine content in leaf was higher than in peel and flesh.The dopamine had a skewed distribution that deviated to the right in cultivars and wild accessions.Finally,the tissue specificity,developmental changes,diurnal changes,and responses to stress were analyzed.In cultivar ‘Pinova’(Malus domestica),the dopamine concentration was the highest in leaf buds and lowest in flesh.The dopamine contents in leaf and flesh decreased with the growth and development of cultivar ‘Liangxiang’(Malus domestica).The dopamine content of apple leaves was higher after either drought or salinity stress as compared to the control.In this study,a dopamine detection method for apple was established based on HPLC-MS and shown to be a robust approach.This study provides a framework for future research on elucidating the tissue distribution,developmental changes,diurnal variation,and stress responses of dopamine in apple trees.展开更多
基金supported by grants from the National Guidance Foundation for Local Science and Technology Development of China(Grant No.2023-009)the Department of Science and Technology of Guizhou Province(Grant No.qiankehezhicheng-[2020]1Y025)。
文摘Phosphorus(Pi)plays a crucial role in the growth and development of plants.Membrane lipid regulation is one of the main mechanisms underlying plant adaptation to Pi deficiency.Previously,the high tolerance to low-Pi stress was justified in an elite line,MSDZ 109,which was obtained from Malus mandshurica.To better understand the mechanism underlying high adaptation to low-Pi stress,currently,lipidomic and transcriptomic analysis,as well as CRISPR/Cas9 and MmGDPD1-overexpressing methodologies were comprehensively integrated into a strategy for elucidating the high tolerance to low-Pi stress.Totally,770 differential metabolites were identified from the roots between the low-Pi and stress-free,belonging to 21 sub-classes of lipid compounds.Fatty acids(FA)constituted the predominant lipid component,accounting for approximately 50%-60%of the total lipids,and triglycerides(TAG)ranked the second,comprising around 12%of the total,consecutively followed by phosphatidylcholine(PC)and diacylglycerol(DAG)with approximately 10%and 8%of the total,respectively.The synchronous transcriptomic analysis revealed a significant up-regulation of genes related to glycerophospholipid and glycerolipid metabolism,specifically those(e.g.,MmGDPD1,MmDGDG1,MmMGDG1,MmSQDG,etc.)involved in phospholipid and galactosyl synthesis in response to low-Pi stress.GUS fusing reporter assay showed that MmGDPD1 promoter induced GUS gene expression and demonstrated initiation activity.Based on expression analysis,a dual-luciferase reporter assay,as well as yeast one-hybrid(Y1H)identification,MmPHR1 was justified to bind with the MmGDPD1 promoter and positively regulate plant tolerance to low-Pi stress.To further elucidate the role of MmGDPD1,CRISPR/Cas9 and MmGDPD1-overexpressing vectors were successfully introduced into apple(‘Royal Gala')calli.Interestingly,the MmGDPD1-KO line calli exhibited the remarkable decreases in the contents of phosphodiesterase(PDE),activity,as well as the contents of total Pi,and Pi in comparison with those of the wild type.Conversely,MmGDPD1-OE ones demonstrated the significant elevation in Pi accumulations,further justifying its potential role in Pi remobilization in apple.Therefore,MmGDPD1 substantially involves elevating low-Pi tolerance via promoting Pi release in M.mandshurica.
基金supported by the Natural Science Foundation of Qinghai Province(2022-ZJ-902).
文摘The use of a stable reference gene is fundamental for achieving reliable quantitative qRT-PCR (qPCR) results. Developing and evaluating the stability of reference genes is necessary for studying the molecular mechanisms of M. transitoria in response to drought stress. In this study, 18 candidate reference genes were selected from transcriptome sequencing data of M. transitoria according to their FPKM values under different drought stress degrees. Cluster-23533.34641 was identified as the most stable reference gene for M. transitoria under drought stress based on qPCR results and combined analysis of Genorm, NormFinder, BestKeeper, and Delta Ct algorithms. The reference genes identified in this research offer improved accuracy for quantifying target gene expression in both M. transitoria and Malus species under drought stress. This study could provide insights into the drought stress-related functional gene or factor in M. transitoria, even in Malus species.
文摘This study aimed to decipher the mechanism by which exogenous methyl jasmonate(MeJA)regulated the photosynthesis of Malus spectabilis leaves under ozone(O_(3))stress.The photosynthetic parameters and chlorophyll fluorescence parameters of M.spectabilis‘Hongjiu’seedlings under O_(3)stress were measured by spraying different concentrations of MeJA.The results showed that O_(3)stress significantly reduced the chlorophyll a and total chlorophyll content,net photosynthetic rate(Pn),stomatal conductance(G_(s)),transpiration rate(T_(r)),maximum fluorescence yield(F_(m)),maximum quantum yield of photosystem II(F_(v)/F_(m)),and actual photochemical efficiency of photosystem II(Ф_(PSII)),while increasing the intercellular CO_(2)concentration(Ci).Exogenous MeJA reduced the Ci and original fluorescence yield(Fo),while increasing chlorophyll a,chlorophyll b,and total chlorophyll content,P_(n),G_(s),T_(r),F_(m),F_(v)/F_(m),andФ_(PSII) of the leaves under O_(3)stress.The application of 150μmol/L MeJA showed the best effect.The above results demonstrated that exogenous MeJA could enhance chlorophyll content and photosynthetic capacity,thereby improving the tolerance of M.spectabilis to O_(3)stress.
基金Supported by Science and Technology Innovation Project of Ji'nan City "Identification of Stress-resistant Malus sieversii Germplasm Resources and Screening of Stressresistance Functional Genes"(201401125)~~
文摘By pot experiment under artificially simulated water stress conditions, soluble protein content, MDA content and SOD, POD, CAT and APX activities in Malus sieversfi leaves were determined to reveal the response mechanism of M. sieversii to changes of relative soil water content. According to the results, with the decrease of relative soil water content, MDA content in M. sieversii leaves increased by mem- brane lipid peroxidation. Cells resist water stress-induced membrane lipid peroxidation and clear the increased reactive oxygen species by improving soluble protein content and SOD, POD, CAT and APX activities. However, various enzymes were involved in the response to water stress under different moisture conditions. In addition, the results indicated that M. sieversii had a good adaptability to higher relative soil water contents.
基金supported by the National Basic Research Special Program of China (2012FY111500)the Innovation Research Group Program of Chinese Academy of Sciences and State Administration of Foreign Experts Affairs of China (KZCX2-YW-T09)+1 种基金the State International Science and Technology Cooperation Program of China (2010DFA92720)the Program of the Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences
文摘Malus sieversii, a wild progenitor of domesticated apple, is distributed in western Xinjiang of China, eastern part of Kazakhstan and Kyrgyzstan in Central Asia. To well understand the genetic structure and the his- torical demography of this important germplasm resource, we sampled 15 populations with 110 individuals of Malus sieversii from the Yili Valley and the western mountains of the Junggar Basin, Xinjiang, and sequenced two nrDNA fragments for these 110 individuals. Meanwhile, we modeled and compared species distributions under the current and the Last Glacial Maximum climatic conditions. The results showed that populations of M. sieversfi from Xinjiang had low levels of genetic diversity and genetic differentiation. During the LGM period, populations of M. sieversfi had lost their northern distributions in the western mountains of the Junggar Basin. M. sieversfi has ex- perienced a demographic expansion from the south of the Yili Valley to the north of the western mountains of the Junggar Basin during the warm interglacial epochs. Due to the high sensibility of M. sieversii to disturbance, we proposed more attention should be paid to the M. sieversfi populations in the western mountains of the Junggar Basin.
基金financially supported by grants from the National Key Research and Development Program of China (Grant No. 2018YFD1000100)Science and Technology Program of Yunnan Province (Grant No. 2019ZG002-1-03)+2 种基金Ministry of Agriculture of China (Grant No. CARS-27)Major Applied Agricultural Technology Innovation Projects of Shandong Province (Grant No.SD2019ZZ009)Melon and Vegetable Industry Technology Collaborative Innovation Center of Ningxia Hui Autonomous Region(Grant No. 2017DC55)。
文摘Plant growth-promoting rhizobacteria(PGPR) located in rhizobacteria soil are beneficial to plant growth and development. A PGPR strain AMCC100017 of Brevibacillus laterosporus synthesizes the plant hormone IAA in a tryptophan-dependent manner. In this study, the AMCC100017 strain was used to treat Malus robusta, an excellent natural rootstock for apple production, and assess its ability to promote growth. The fresh weight, dry weight, plant height, and lateral root growth of M. robusta were significantly increased with treatment. The presence of the AMCC100017 strain increased IAA content in M. robusta and promoted root secretion of tryptophan. Colonization of the strain in the roots allowed continuous synthesis of IAA and promoted plant growth. In addition, the photosynthetic efficiency in leaves increased after microbial treatment, and the utilization of nitrogen, zinc, iron, copper and magnesium in leaves was increased, which was conducive to photosynthesis.Interestingly, the activities of CAT and SOD, as well as the contents of ROS in plants colonized by AMCC100017 were increased compared to control plants, but the activities of POD and MDA contents were decreased. AMCC100017 strain affected the antioxidant capacity and stress resistance of plants. AMCC100017 strain increased the content of soluble protein and soluble sugar in plants, improved plant metabolic activity and stress resistance. Therefore, AMCC100017 not only increased IAA content and photosynthetic efficiency to promote M. robusta growth, but also affected plant through multiple metabolic pathways.
文摘What the researchers go in for is to establish models between root architecture （RA） changes and nutrition, mold ideal root architecture of apple trees, improve the nutrient uptake efficiency, and further explore the functional mechanism of nutrient elements during the course of RA construction. The cultivation system of filter paper is utilized to research the effect of nutrient deficiency on the RA of Malus hupehensis （Pamp.） Rehd. There may be eight types of RA. In complete Hogland solution, the main type of RA is ＂lateral roots clustering in the upper and middle regions of primary root＂. With the lack of P, K or Ca, the main type of RA is ＂lateral roots clustering in the upper region primary root＂, and the ＂lateral roots clustering in the upper and middle regions of primary root＂ types of RA decrease. But with shortage of P, the type of lateral roots clustering in the upper and lower regions of primary root increases, and the type of lateral roots clustering in the middle region of primary root decreases, with the types of RA diversified. Under the condition of K deficiency, the type of no lateral root increases and types of lateral roots clustering in the middle region of primary root decrease, and the percentage of such types as ＂no lateral root＂, ＂lateral roots clustering in the upper region of primary root＂, and ＂lateral roots clustering in the upper and middle regions of primary root＂ accounts for 97.9% in all, with the types of RA simplified. With lack of Fe, Mg or Zn, the main type of RA is ＂lateral roots clustering in the upper and middle regions of primary root＂, but the type of lateral roots evenly-distributed on primary root increases. The main type of RA is ＂lateral roots evenlydistributed on primary root＂, under the condition of N deficiency, and the types of RA turn out to be diversified. There exists a close relation between nutrient deficiency and RA changes. Owing to various forms of nutrient deficiency, correspondingly different types of RA have been produced.
基金suppoted by the Project of 948 from Ministry of Agriculture of China (2006-G28)the Non-profit Research Foundation from Ministry of Agriculture of China (nyhyzx07-024)+1 种基金the Ear Marked Fund for Modern Agro-Industry Technology Research System, Chinathe Key Innovation Project for Agricultural Application Technology of Shandong Province, China.
文摘This paper studied the effects of cinnamon acid treatments on the respiratory rate and related enzymes activity in the seedling roots of Malus hupehensis Rehd.It would provide information for understanding the mechanisms of inhibition damage caused by continuous cultivation of apple tree.20 mL of solution containing different concentrations of cinnamon acid was added into container with the tested seedlings.After treatment,the samples were taken periodically and the respiratory rates were measured by OXY-LAB oxygen electrodes under 25°C stable temperature and then the activities of related enzymes were measured.The rates of total respiration and other 2 pathways [tricarboxylic acid cycle （TCA） and pentose phosphate pathway （PPP）] appeared initially an increasing treads and late （on the 3rd d） began to decline.However,they again appeared an increase trend at the end period,on the contrast,the respiratory rate of embden-meyer- hot-parnas （EMP） pathway appeared a stead decline tread but it had a recover on the last day.The respiratory rate of total and 3 pathways were decreased under 125 mg kg-1 （soil）.The dynamic trends of the enzymes activities of pyrophosphate-dependent phosphofructokinase （PFK）,glucose-6-phosphate dehydrogenase （G-6-PDH） and malate dehydrogenase （MDH） showed similarly.In conclusion,treatments of certain concentration of cinnamon acid would inhibit the respiratory rate and related enzymes activity of roots of M.hupehensis Rehd.And the inhibition degrees were positively related with concentration of cinnamon acid treatments.
基金the program of Technology Development Program of Shandong Province, China(2007GG20009013)
文摘Volatile compounds from the ripened crabapple fruit of six varieties （Red Splendor, Strawberry Parfait, Pink Spire, Radiant, Sparkler, and Flame） were analyzed by the use of the SPME/GC/MS method. The changes in the volatiles between the ripened and upon full maturity fruit states were studied in Red Splendor and Strawberry Parfait. An effort was made to summarize an effective method for searching and identifying new idioplasms containing a particular fruit aroma within Malus. A total of 37 compounds were identified from the sample. The main aroma volatiles of the six varieties of fruit were comprised of 2-hexenal, 3-hexenal, hexanal, 2,4-hexadienal, benzaldehyde, diethyl phtbalate. The main volatile compound of the crabapple fruit was 2-hexenal, but the relative content percentages were different （45.37, 21.98, 33.56, 32.21, 38.60, and 45.88%）. The aroma components accumulated differently as the fruits ripened. The relative content of aldehydes and esters decreased as alcohols increased after the Red Splendor and Strawberry Parfait fruit ripened. For Red Splendor, the main volatile was still 2-hexenal, but the relative content decreased to 42.89%, and the relative content of alcohols increased by 13.86% as aldehydes and esters declined by 12.16 and 7.18%, respectively. For Strawberry Parfait, the main volatile was changed to cyclohexanol, and the relative content increased to 46.43%, while the relative content of alcohols increased by 49.03% as aldehydes and esters declined by 23.74 and 9.34%, respectively.
基金the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences(CAAS-ASTIP).
文摘China is a center of diversity for Malus Mill,with 27 native species including 21 wild species and six domesticated species.We applied a set of 19 simple sequence repeat markers to genotype 798 accessions of 17 species(12 wild species and five cultivated species)of Malus originating from 14 provinces in China.A total of 500 alleles were detected.Diversity statistics indicated a high level of genetic variation as quantified by the average values of the effective allele number(N_(e)).expected heterozygosity(H_(e)),and Shannon's Information Index(I)(10.309,0.886,and 2.545,respectively).Malus sieversii(MSR;H_(e)=0.814,I=2.041,N_(e)=6.054),M.baccata(MBB;H_(e)=0.848,/=2.350,N_(e)=8.652),M.toringoides(MTH;He=0.663,I=1.355,N_(e)=3.332),and M.hupehensis(MHR;H_(e)=0.539,I=0.912,N_(e)=0.579)showed a higher level of genetic diversity in this study than the previous studies.MSR and MBB contributed to the origin and evolution of some accessions of M.domestica subsp.chinensis(MDC).However,other accessions of MDC showed a closer genetic distance with MBB and cultivated species,especially M.robusta(MRB),M.asiatica(MAN),and M.prunifolia(MPB).Not all accessions of MDC were descended from MSR in Xinjiang Uygur Autonomous Region of China.This research provides novel insights into the genetic relationships of Malus native to China,which will be useful for genetic association studies,germplasm conservation,and breeding programs.
基金This work was supported by the National Key Research and Development Program of China(2018YFD1000303)the National Natural Science Foundation of China(31972389)+1 种基金the Natural Science Basic Research Plan in Shaanxi Province,China(2018JQ3001)Cyrus Tang Foundation,Northwest A&F University,China.The authors are grateful to Ms.Christina E.W.(Senior Editor,The Pennsylvania State University)for editing the language of the article.
文摘Dopamine plays numerous physiological roles in plants.We explored its role in the regulation of growth,nutrient absorption,and response to nitrogen(N)deficiency in Malus hupehensis Rehd.Under low N condition,plant growth slowed,and the net photosynthetic rates,chlorophyll contents,and maximal quantum yield of PSII(Fv/Fm)decreased significantly.However,the application of 100μmol L−1 exogenous dopamine significantly reduced the inhibition of low N stress on plant growth.In addition to modifying root system architecture under low N supply,exogenous dopamine also changed the uptake,transport,and distribution of N,P,and K.Furthermore,exogenous dopamine enhances the tolerance to low nitrogen stress by increasing the activity of enzymes(nitrate reductase,nitrite reductase,glutamic acid synthase and glutamine synthetase)involved in N metabolism.We also found that exogenous dopamine promoted the expression of ethylene signaling genes(ERF1,ERF2,EIL1,ERS2,ETR1,and EIN4)under low N stress.Therefore,we hypothesized that ethylene might be involved in dopamine response to low N stress in M.hupehensis.Our results suggest that exogenous dopamine can mitigate low N stress by regulating the absorption of mineral nutrients,possibly through the regulation of the ethylene signaling pathway.
基金supported by the National Natural Science Foundation of China (31622049 and 31572106)the Key Program of the National Natural Science Foundation of China (31330068)+1 种基金the Program of Sci-Tech Star of Shaanxi, China (2015kjxx14)the startup funding (Z111021402) from Northwest A&F University to Guan Qingmei who is also supported by the Thousand Talents Plan of China
文摘Water deficit is one of the main limiting factors for apple growth and production.Root architecture plays an important role in drought tolerance of plants.However,little is known about the molecular basis of root system in apple trees under drought.In this study,we compared root morphology of two widely used rootstocks of apple(R3 and Malus sieversii)under drought.Our results suggested that M.sieversii is more tolerant to drought than R3,since M.sieversii had a higher ratio of root to shoot as well as root hydraulic conductivity under long-term drought conditions.We then performed whole-genome transcriptomic analysis to figure out the molecular basis of root responses in M.sieversii under drought.It was found that genes involved in transcription regulation,signaling or biosynthesis of hormones,and oxidative stress were differentially expressed under drought.Consistent with the gene expression profile,roots of M.sieversii had higher activities of peroxidase(POD)and superoxide dismutase(SOD)under drought,as well as higher content of abscisic acid(ABA)and lower content of auxin.Taken together,our results revealed the physiological and transcriptomic analyses of M.sieversii roots in response to drought.
基金financially supported by the National Natural Science Foundation of China (30871679)National 863 Program of China (2006AA100108)Agricultural Improved Variety Project of Shandong Province, China.
文摘The method for constructing core collection ofMalus sieversii based on molecular marker data was proposed. According to 128 SSR allele of 109 M. sieversii, an allele preferred sampling strategy was used to construct M. sieversii core collection, using the UPGMA （unweighted pair-group average method） cluster method according to Nei ＆ Li, SM, and Jaccard genetic distances, by stepwise clustering, and compared with the random sampling strategy. The number of lost allele and t-test of Nei＇s gene diversity and Shannon＇s information index were used to evaluate the representative core collections. The results showed that compared with the random sampling strategy, allele preferred sampling strategy could construct more representative core collections. SM, difference for construction of M. sieversii core collection. Jaccard, and Nei ＆ Li genetic distances had no significant SRAP （sequence-related amplified polymorphism） data and morphological data showed that allele preferred sampling strategy was a good sampling strategy for constructing core collection of M. sieversii. Allele preferred sampling strategy combined with SM, Jaccard, and Nei ＆ Li genetic distances using stepwise clustering was the suitable method for constructing M. sieversii core collection.
基金supported by the National Special Funds for Scientific Research on Public Causes(Agriculture) Project 3-22,China (nyhyzx07-024)the National High-Tech R&D Program of China (863 Program,2006AA100108 and 2006AA10Z1B6)
文摘Apple bot canker [Botryosphaeria dothidea（Moug.） Ces.et de Not.] is distributed worldwide,resulting in a serious crop loss every year in apple（Malus domestica Borkh.） production.The resistance of each seedling derived from a hybrid population（Jonathan×Golden Delicious） was evaluated by disease index either from natural infection in the field or from inoculation with five isolates of B.dothidea,Ls1,Lw023,Lw048,Mx1,and Zz26.The inheritance of the resistance to bot canker was analyzed via frequency distribution analysis,and microsatellite and AFLP markers linked to the resistance loci were screened.From the binary frequency distribution patterns,it was found that the segregation ratio of resistant/susceptible genotypes infected by pathogen isolates Lw023 and Ls1 was 1：15;and that by Zz26 and Mx1 was 15：1.The variation of resistance was involved in the segregation of two to four alleles of major genes,the resistance was recessive when infected by Lw023 and Ls1,but was dominant when infected with Mx1 and Zz26.A microsatellite maker,CH02a04-450,and two AFLP markers,E-AG/M-GAC-280 and E-AGG/M-CTT-110,were identified,and their map distances to the resistance loci were 5.1,5.1 and 6.2 cM,respectively.The three markers are located in different linkage groups,while CH02a04-450 is on linkage group 2 or 7.E-AG/M-GAC-280 was successfully converted into SCAR159.Finally,CH02a04-450 and SCAR159 were re-examined in inoculated segregation population and presented a good reliability on predicting phenotypes of resistance.
基金the National Natural Science Foundation of China (30671452 and 31171923)
文摘The free putrescine （Put） content, the hydrogen peroxide （H202） content and the polyamine oxidase （PAO） activity in roots of Malus hupehensis Rehd. var. pinyiensis Jiang （PYTC） were significantly increased, and reached its peak at 1, 2 and 6 h, respectively, under cadmium treatment. The free spermine （Spin） and spermidine （Spd） contents were dramatically decreased, and reached the minimum value at 4-6 h, then remained relatively stable. The change in total free polyammes （PAs） content was consistent with that of free Put. The number of root dead cells was gradually increased after treatment for 24 h, and the typical characteristics of programmed cell death （PCD） were displayed at 48 h. Throughout the Cd treatment process, changes in PAs metabolism appeared to be prior to cell death increase, and the H2O2 content was always maintained at a high level. These results indicated that polyamines could initiate cell death by generating H2O2 in roots of Malus hupehensis Rehd. under CdSO4 stress.
基金supported by the National Key Research and Development Program of China (2019YFD1001403– 2B)the China Agriculture Research System of MOF and MARA (CARS-27)the National Natural Science Foundation of China (31972389)。
文摘Dopamine is a catecholamine and an anti-oxidant which functions in responses to stress and it interacts with plant hormones to mediate plant development.At present,there are few studies on the functions of dopamine in apple.This study developed a method for dopamine determination which was used to analyze dopamine in Malus germplasm,in order to clarify the tissue distribution,developmental changes,diurnal variations,and stress responses in apple trees.First,the proposed method was verified.The linear range of quantification was robust from 0.1 to 20 ng mL^(–1).The instrumental,inter-day precision,and sample repeatability relative standard deviations were 1.024,5.607,and 7.237%,respectively.The spiked recovery was greater than 100%,indicating the feasibility of the method and its suitability for the rapid analysis of dopamine in Malus.Next,the dopamine content was measured in 322 Malus tissues.The results showed that the dopamine level in Malus was low and the average dopamine content in leaf was higher than in peel and flesh.The dopamine had a skewed distribution that deviated to the right in cultivars and wild accessions.Finally,the tissue specificity,developmental changes,diurnal changes,and responses to stress were analyzed.In cultivar ‘Pinova’(Malus domestica),the dopamine concentration was the highest in leaf buds and lowest in flesh.The dopamine contents in leaf and flesh decreased with the growth and development of cultivar ‘Liangxiang’(Malus domestica).The dopamine content of apple leaves was higher after either drought or salinity stress as compared to the control.In this study,a dopamine detection method for apple was established based on HPLC-MS and shown to be a robust approach.This study provides a framework for future research on elucidating the tissue distribution,developmental changes,diurnal variation,and stress responses of dopamine in apple trees.
