Interspecific hybridization and allopolyploidization contribute to the improvement of many important crops. Recently, we successfully developed an amphidiploid from an interspecific cross between cucumber(Cucumis sati...Interspecific hybridization and allopolyploidization contribute to the improvement of many important crops. Recently, we successfully developed an amphidiploid from an interspecific cross between cucumber(Cucumis sativus, 2n = 2x = 14) and its relative C. hystrix(2n = 2x = 24) followed by chemical induction of chromosome doubling. The resulting allotetraploid plant was self-pollinated for three generations. The fertility and seed set of the amphidiploid plants were very low. In this study, we investigated the meiotic chromosome behavior in pollen mother cells with the aid of fluorescence in situ hybridization, aiming to identify the reasons for the low fertility and seed set in the amphidiploid plants. Homologous chromosome pairing appeared normal, but chromosome laggards were common, owing primarily to asynchronous meiosis of chromosomes from the two donor genomes. We suggest that asynchronous meiotic rhythm between the two parental genomes is the main reason for the low fertility and low seed set of the C. hystrix–cucumber amphidiploid plants.展开更多
Cucumber,Cucumis sativus is an important vegetable crop,and gynoecy has played a critical role in yield increase of hybrid cucumber production.Cucumber has a unique genetic system for gynoecious sex expression,which i...Cucumber,Cucumis sativus is an important vegetable crop,and gynoecy has played a critical role in yield increase of hybrid cucumber production.Cucumber has a unique genetic system for gynoecious sex expression,which is determined by the copy number variation(CNV)-based,dominant,and dosage-dependent femaleness(F)locus.However,this gynoecy expression system seems unstable since monecious plants could often be found in Fdependent gynoecious cucumber inbreds.We hypothesized that gynoecy instability(gynoecy loss)may be due to unequal crossing over(UCO)during meiosis among repeat units of the CNV.In this study,using high throughput genome resequencing,fiber-FISH and genomic qPCR analyses,we first confirmed and refined the structure of the F locus,which was a CNV of a 30.2-kb tandem repeat.Gynoecious plants contained three genes:CsACS1,CsACS1G,and CsMYB,of which CsACS1G is a duplication of CsACS1 but with a recombinant distal promoter that may contribute to gynoecy sex expression.In two large populations from self-pollinated gynoecious inbred lines,‘gynoecy loss’mutants were identified with similar mutation rates(~0.12%).We show that these monecious mutants have lost CsACS1G.In addition,we identified gynoecious lines in natural populations that carry two copies of CSACS1G.We proposed a model to explain gynoecy instability in F-dependent cucumbers,which is caused by UCO among CSACS1/G units during meiosis.The findings present a convincing case that the phenotypic variation of an economically important trait is associated with the dynamic changes of copy numbers at the F locus.This work also has important implications in cucumber breeding.展开更多
The rare earth element cerium（Ce） in its several forms is extensively utilized in various fields, including nano-technology, agriculture, and the food industry. Due to its increasing unregulated usage, Ce is now a p...The rare earth element cerium（Ce） in its several forms is extensively utilized in various fields, including nano-technology, agriculture, and the food industry. Due to its increasing unregulated usage, Ce is now a potential source of pollution and toxicity due to its excessive environmental accumulation. Unfortunately, analysis of the toxic effects of Ce in plants is still in its early stages. Herein, we investigated the effects of Ce3＋ treatment on development-related indicators in sweetpotato. We found that a low concentration（10 mg/L） slightly improved oxidation resistance, while a high concentration（20-80 mg/L）negatively affected development and photosynthesis and triggered increases in reactive oxygen species（ROS） production, antioxidant enzyme activities, and malondialdehyde（MDA） content. Moreover,elevation and efflux of cytosolic Ca^（2＋） and caspase-l-like activity were induced by high-concentration Ce^（3＋） treatment. Finally, cell viability decreased as Ce3＋ concentration increased. These results suggest that（1） a high Ce3＋ concentration（20-80 mg/L） inhibits development and photosynthesis of sweetpotato and induces oxidative damage followed by lipid peroxidation in the root,（2） a caspase-l-like protease is induced by cytosolic Ca^（2＋） and ROS overproduction to cause programmed cell death in the root, and（3） a high concentration of Ce3＋ could trigger a hypothetical cell death pathway, wherein Ce3＋induces ROS production followed by cytosolic Ca^（2＋） elevation, which activates caspase-l-like activity,which in turn leads to programmed cell death in the root of sweetpotato.展开更多
High salinity is one of the major limiting fac-tors that reduces crop productivity and quality.Herein,we report that small SALT TOLERANCE ENHANCER1(STE1)protein without any known conserved domains is required for toma...High salinity is one of the major limiting fac-tors that reduces crop productivity and quality.Herein,we report that small SALT TOLERANCE ENHANCER1(STE1)protein without any known conserved domains is required for tomato salt tolerance.Overexpression(OE)of SlSTE1 enhanced the tolerance to multiple chloride salts(NaCl,KCl,and LiCl)and oxidative stress,along with elevated antioxidant enzyme activities,increased abscisic acid(ABA)and chlorophyll contents,and reduced ma-londialdehyde(MDA)and reactive oxygen species(ROS)accumulations compared to that of wild-type(WT)plants.Moreover,decreased K^+efflux and increased H^+efflux were detected in the OE plants,which induced a higher K^+/Na^+ratio.In contrast,SlSTE1-RNAi plants dis-played decreased tolerance to salt stress.RNA-seq data revealed 1330 differentially expressed genes in the OE plants versus WT plants under salt stress,and the tran-scription of numerous and diverse genes encoding transcription factors,stress-related proteins,secondary metabolisms,kinases,and hormone synthesis/signaling-related proteins(notably ABA and 1-aminocyclopropane-1-carboxylate)was greatly elevated.Furthermore,SlSTE1-OE plants showed increased sensitivity to ABA,and the results suggest that SlSTE1 promotes ABA-dependent salt stress-responsive pathways by interacting with SlPYLs and SlSnRK2s.Collectively,our findings reveal that the small SlSTE1 protein confers salt tolerance via ABA sig-naling and ROS scavenging and improves ion homeo-stasis in tomato.展开更多
基金supported by Agriculture and Food Research Initiative Competitive Grant 2013-67013-21105 from the U.S. Department of Agriculture National Institute of Food to YWthe National Natural Science Foundation of China to YH (No. 31271350)
文摘Interspecific hybridization and allopolyploidization contribute to the improvement of many important crops. Recently, we successfully developed an amphidiploid from an interspecific cross between cucumber(Cucumis sativus, 2n = 2x = 14) and its relative C. hystrix(2n = 2x = 24) followed by chemical induction of chromosome doubling. The resulting allotetraploid plant was self-pollinated for three generations. The fertility and seed set of the amphidiploid plants were very low. In this study, we investigated the meiotic chromosome behavior in pollen mother cells with the aid of fluorescence in situ hybridization, aiming to identify the reasons for the low fertility and seed set in the amphidiploid plants. Homologous chromosome pairing appeared normal, but chromosome laggards were common, owing primarily to asynchronous meiosis of chromosomes from the two donor genomes. We suggest that asynchronous meiotic rhythm between the two parental genomes is the main reason for the low fertility and low seed set of the C. hystrix–cucumber amphidiploid plants.
基金supported by the National Natural Science Foundation of China(Nos.31672150 and 31872111)the Fundamental Research Fund for the Central Universities(2452016004)and the Key Research and Development Plan(2018NY-034)of Shaanxi Province.Work in Y.Q.W.’s lab was supported by USDA National Institute of Food and Agriculture under following award numbers 2015-51181-24285 and 2017-67013-26195.USDA is an equal opportunity provider and employer.
文摘Cucumber,Cucumis sativus is an important vegetable crop,and gynoecy has played a critical role in yield increase of hybrid cucumber production.Cucumber has a unique genetic system for gynoecious sex expression,which is determined by the copy number variation(CNV)-based,dominant,and dosage-dependent femaleness(F)locus.However,this gynoecy expression system seems unstable since monecious plants could often be found in Fdependent gynoecious cucumber inbreds.We hypothesized that gynoecy instability(gynoecy loss)may be due to unequal crossing over(UCO)during meiosis among repeat units of the CNV.In this study,using high throughput genome resequencing,fiber-FISH and genomic qPCR analyses,we first confirmed and refined the structure of the F locus,which was a CNV of a 30.2-kb tandem repeat.Gynoecious plants contained three genes:CsACS1,CsACS1G,and CsMYB,of which CsACS1G is a duplication of CsACS1 but with a recombinant distal promoter that may contribute to gynoecy sex expression.In two large populations from self-pollinated gynoecious inbred lines,‘gynoecy loss’mutants were identified with similar mutation rates(~0.12%).We show that these monecious mutants have lost CsACS1G.In addition,we identified gynoecious lines in natural populations that carry two copies of CSACS1G.We proposed a model to explain gynoecy instability in F-dependent cucumbers,which is caused by UCO among CSACS1/G units during meiosis.The findings present a convincing case that the phenotypic variation of an economically important trait is associated with the dynamic changes of copy numbers at the F locus.This work also has important implications in cucumber breeding.
基金Project supported by the National Natural Science Foundation of China(31271698,31771367)The Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)China Agriculture Research System(CARS-10)
文摘The rare earth element cerium（Ce） in its several forms is extensively utilized in various fields, including nano-technology, agriculture, and the food industry. Due to its increasing unregulated usage, Ce is now a potential source of pollution and toxicity due to its excessive environmental accumulation. Unfortunately, analysis of the toxic effects of Ce in plants is still in its early stages. Herein, we investigated the effects of Ce3＋ treatment on development-related indicators in sweetpotato. We found that a low concentration（10 mg/L） slightly improved oxidation resistance, while a high concentration（20-80 mg/L）negatively affected development and photosynthesis and triggered increases in reactive oxygen species（ROS） production, antioxidant enzyme activities, and malondialdehyde（MDA） content. Moreover,elevation and efflux of cytosolic Ca^（2＋） and caspase-l-like activity were induced by high-concentration Ce^（3＋） treatment. Finally, cell viability decreased as Ce3＋ concentration increased. These results suggest that（1） a high Ce3＋ concentration（20-80 mg/L） inhibits development and photosynthesis of sweetpotato and induces oxidative damage followed by lipid peroxidation in the root,（2） a caspase-l-like protease is induced by cytosolic Ca^（2＋） and ROS overproduction to cause programmed cell death in the root, and（3） a high concentration of Ce3＋ could trigger a hypothetical cell death pathway, wherein Ce3＋induces ROS production followed by cytosolic Ca^（2＋） elevation, which activates caspase-l-like activity,which in turn leads to programmed cell death in the root of sweetpotato.
基金This work was supported by the National NaturalScience Foundation of China(31700226)and the Pri-ority Academic Program Development of JiangsuHigher Education lnstitutions(PAPD).
文摘High salinity is one of the major limiting fac-tors that reduces crop productivity and quality.Herein,we report that small SALT TOLERANCE ENHANCER1(STE1)protein without any known conserved domains is required for tomato salt tolerance.Overexpression(OE)of SlSTE1 enhanced the tolerance to multiple chloride salts(NaCl,KCl,and LiCl)and oxidative stress,along with elevated antioxidant enzyme activities,increased abscisic acid(ABA)and chlorophyll contents,and reduced ma-londialdehyde(MDA)and reactive oxygen species(ROS)accumulations compared to that of wild-type(WT)plants.Moreover,decreased K^+efflux and increased H^+efflux were detected in the OE plants,which induced a higher K^+/Na^+ratio.In contrast,SlSTE1-RNAi plants dis-played decreased tolerance to salt stress.RNA-seq data revealed 1330 differentially expressed genes in the OE plants versus WT plants under salt stress,and the tran-scription of numerous and diverse genes encoding transcription factors,stress-related proteins,secondary metabolisms,kinases,and hormone synthesis/signaling-related proteins(notably ABA and 1-aminocyclopropane-1-carboxylate)was greatly elevated.Furthermore,SlSTE1-OE plants showed increased sensitivity to ABA,and the results suggest that SlSTE1 promotes ABA-dependent salt stress-responsive pathways by interacting with SlPYLs and SlSnRK2s.Collectively,our findings reveal that the small SlSTE1 protein confers salt tolerance via ABA sig-naling and ROS scavenging and improves ion homeo-stasis in tomato.
