查看更多>>摘要：Pumpkin CmoNAC1 enhances salt tolerance in grafted cucumbers.However,the potential interactions with other proteins that may co-regulate salt tolerance alongside CmoNAC1 have yet to be explored.In this study,we identified pumpkin CmoDREB2A as a pivotal transcription factor that interacts synergistically with CmoNAC1 in the co-regulation of salt tolerance.Both transcription factors were observed to bind to each other's promoters,forming a positive regulatory loop of their transcription.Knockout of CmoDREB2A in the root resulted in reduced salt tolerance in grafted cucumbers,whereas overexpression demonstrated the opposite effect.Multiple assays in our study provided evidence of the protein interaction between CmoDREB2A and CmoNAC1.Exploiting this interaction,CmoDREB2A facilitated the binding of CmoNAC1 to the promoters of CmoRBOHD1,CmoNCED6,CmoAKT1;2,and CmoHKT1;1,inducing H2O2 and ABA synthesis and increasing the K+/Na+ratio in grafted cucumbers under salt stress.Additionally,CmoNAC1 also promoted the binding of CmoDREB2A to CmoHAK5;1/CmoHAK5;2 promoters,further contributing to the K+/Na+homeostasis.In summary,these findings reveal a crucial mechanism of CmoNAC1 and CmoDREB2A forming a complex enhancing salt tolerance in grafted cucumbers.
查看更多>>摘要：Platycodon grandiflorus(Jacq.)A.DC,known for its saponin content,can potentially prevent and treat cerebrovascular diseases and COVID-19.Triterpenoid saponin biosynthesis in plants is enhanced by methyl jasmonate(MeJA)application.However,the underlying molecular mechanisms of MeJA-induced saponin biosynthesis remain unknown in P.grandiflorus.In the current study,exogenous application of 100 μ mol/l MeJA was identified to be optimal for promoting saponin accumulation.RNA sequencing analysis demonstrated the PgbHLH28 gene as a key regulatory factor responding to MeJA during saponin accumulation.Overexpression of PgbHLH28 in P.grandiflorus increased saponin content,while silencing of PgbHLH28 significantly inhibited saponin synthesis,suggesting that PgbHLH28 acts as a positive regulator of saponin biosynthesis.Yeast one-hybrid and dual luciferase assays demonstrated that PgbHLH28 directly bound to the promoters of PgHMGR2 and PgDXS2 to activate gene expression.PgHMGR2 and PgDXS2 transformation promoted saponin accumulation,while silencing of these genes inhibited saponin biosynthesis.This study determined that MeJA promoted saponin accumulation in P.grandiflorus by inducing PgbHLH28 gene expression and activating downstream genes(PgHMGR2 and PgDXS2)involved in saponin biosynthesis.In conclusion,a complex regulatory network governing saponin biosynthesis following MeJA treatment was elucidated,offering a theoretical foundation for enhancing saponin content and biosynthesis efficacy in P.grandiflorus.
查看更多>>摘要：High levels of free amino acids(AAs)in tea leaves are crucial for tea flavor and health function;however,the dynamic AA biosynthesis,transport,and turnover in tea plants remain elusive.Here we dissected whole tea plants for these dynamics by assessing AA profiles and transcriptomes of metabolic pathway genes in tea roots,stems,and leaves and revealing their distinctive features with regard to AA synthesis,transport,and degradation/recycling.Nitrogen assimilation dominated in the roots wherein glutamine(Gln),theanine,and arginine(Arg)were actively synthesized.Arg was transported into trunk roots and stems,together with Glu,Gln,and theanine as the major AAs in the xylem sap for long-distance root-to-leaf transport.Transcriptome analysis revealed that genes involved in Arg synthesis were highly expressed in roots,but those for Arg transport and degradation were highly expressed in stems and young leaves,respectively.CsGSIa transcripts were found in root meristem cells,root,stem and leaf vascular tissues,and leaf mesophyll where it appeared to participate in AA synthesis,transport,and recycling.Overexpression of CsGSIa in tea transgenic hairy roots and knockdown of CsGSIa in transgenic hairy roots and tea leaves produced higher and lower Gln and theanine than wild-type roots and leaves,respectively.This study provides comprehensive and new insights into AA metabolism and transport in the whole tea plant.
查看更多>>摘要：Broccoli(Brassica oleracea var.italica Plenck)is an important vegetable crop,as it is rich in health-beneficial glucosinolates(GSLs).However,the genetic basis of the GSL diversity in Brassicaceae remains unclear.Here we report a chromosome-level genome assembly of broccoli generated using PacBio HiFi reads and Hi-C technology.The final genome assembly is 613.79 Mb in size,with a contig N50 of 14.70 Mb.The GSL profile and content analysis of different B.oleracea varieties,combined with a phylogenetic tree analysis,sequence alignment,and the construction of a 3D model of the methylthioalkylmalate synthase 1(MAM1)protein,revealed that the gene copy number and amino acid sequence variation both contributed to the diversity of GSL biosynthesis in B.oleracea.The overexpression of BoMAM1(BolI0108790)in broccoli resulted in high accumulation and a high ratio of C4-GSLs,demonstrating that BoMAM1 is the key enzyme in C4-GSL biosynthesis.These results provide valuable insights for future genetic studies and nutritive component applications of Brassica crops.
查看更多>>摘要：CaWRKY40 coordinately activates pepper immunity against Ralstonia solanacearum infection(RSI)and high temperature stress(HTS),forms positive feedback loops with other positive regulators and is promoted by CaWRKY27b/CaWRKY28 through physical interactions;however,whether and how it is regulated by negative regulators to function appropriately remain unclear.Herein,we provide evidence that CaWRKY40 is repressed by a SALT TOLERANCE HOMOLOG2 in pepper(CaSTH2).Our data from gene silencing and transient overexpression in pepper and epoptic overexpression in Nicotiana benthamiana plants showed that CaSTH2 acted as negative regulator in immunity against RSI and thermotolerance.Our data from BiFC,CoIP,pull down,and MST indicate that CaSTH2 interacted with CaWRKY40,by which CaWRKY40 was prevented from activating immunity or thermotolerance-related genes.It was also found that CaSTH2 repressed CaWRKY40 at least partially through blocking interaction of CaWRKY40 with CaWRKY27b/CaWRKY28,but not through directly repressing binding of CaWRKY40 to its target genes.The results of study provide new insight into the mechanisms underlying the coordination of pepper immunity and thermotolerance.
查看更多>>摘要：The low phosphorus(P)availability of acidic soils severely limits leguminous plant growth and productivity.Improving the soil P nutritional status can be achieved by increasing the P-content through P-fertilization or stimulating the mineralization of organic P via arbuscular mycorrhizal fungi(AMF)application;however,their corresponding impacts on plant and soil microbiome still remain to be explored.Here,we examined the effects of AMF-inoculation and P-fertilization on the growth of soybean with different P-efficiencies,as well as the composition of rhizo-microbiome in an acidic soil.The growth of recipient soybean NY-1001,which has a lower P-efficiency,was not significantly enhanced by AMF-inoculation or P-fertilization.However,the plant biomass of higher P-efficiency transgenic soybean PT6 was significantly increased by 46.74％-65.22％through AMF-inoculation.Although there was no discernible difference in plant biomass between PT6 and NY-1001 in the absence of AMF-inoculation and P-fertilization,PT6 had approximately 1.9-2.5 times the plant biomass of NY-1001 after AMF-inoculation.Therefore,the growth advantage of higher P-efficiency soybean was achieved through the assistance of AMF rather than P-fertilization in available P-deficient acidic soil.Most nitrogen(N)-fixing bacteria and some functional genes related to N-fixation were abundant in endospheric layer,as were the P-solubilizing Pseudomonas plecoglossicida,and annotated P-metabolism genes.These N-fixing and P-solubilizing bacteria were positive correlated with each other.Lastly,the two most abundant phytopathogenic fungi species accumulated in endospheric layer,they exhibited positive correlations with N-fixing bacteria,but displayed negative interactions with the majority of the other dominant non-pathogenic genera with potential antagonistic activity.
查看更多>>摘要：Salinity stress causes serious damage to crops worldwide,limiting plant production.However,the metabolic and molecular mechanisms underlying the response to salt stress in rose(Rosa spp.)remain poorly studied.We therefore performed a multi-omics investigation of Rosa hybrida cv.Jardin de Granville(JDG)and Rosa damascena Mill.(DMS)under salt stress to determine the mechanisms underlying rose adaptability to salinity stress.Salt treatment of both JDG and DMS led to the buildup of reactive oxygen species(H2O2).Palisade tissue was more severely damaged in DMS than in JDG,while the relative electrolyte permeability was lower and the soluble protein content was higher in JDG than in DMS.Metabolome profiling revealed significant alterations in phenolic acid,lipids,and flavonoid metabolite levels in JDG and DMS under salt stress.Proteome analysis identified enrichment of flavone and flavonol pathways in JDG under salt stress.RNA sequencing showed that salt stress influenced primary metabolism in DMS,whereas it substantially affected secondary metabolism in JDG.Integrating these datasets revealed that the phenylpropane pathway,especially the flavonoid pathway,is strongly enhanced in rose under salt stress.Consistent with this,weighted gene coexpression network analysis(WGCNA)identified the key regulatory gene chalcone synthase 1(CHS1),which is important in the phenylpropane pathway.Moreover,luciferase assays indicated that the bHLH74 transcription factor binds to the CHS1 promoter to block its transcription.These results clarify the role of the phenylpropane pathway,especially flavonoid and flavonol metabolism,in the response to salt stress in rose.
查看更多>>摘要：In flowering plants,male gametogenesis is tightly regulated by numerous genes.Mitogen-activated protein kinase(MAPK)plays a critical role in plant development and stress response,while its role in plant reproductive development is largely unclear.The present study demonstrated MAPK20 phosphorylation of ATG6 to mediate pollen development and germination in tomato(Solanum lycopersicum L.).MAPK20 was preferentially expressed in the stamen of tomato,and mutation of MAPK20 resulted in abnormal pollen grains and inhibited pollen viability and germination.MAPK20 interaction with ATG6 mediated the formation of autophagosomes.Liquid chromatography-tandem mass spectrometry(LC-MS/MS)analysis showed that ATG6 was phosphorylated by MAPK20 at Ser-265.Mutation of ATG6 in wild-type(WT)or in MAPK20 overexpression plants resulted in malformed and inviable pollens.Meanwhile,the number of autophagosomes in mapk20 and atg6 mutants was significantly lower than that of WT plants.Our results suggest that MAPK20-mediated ATG6 phosphorylation and autophagosome formation are critical for pollen development and germination.
查看更多>>摘要：Citric acid(CA)plays a crucial role as a fruit flavor enhancer and serves as a mediator in multiple metabolic pathways in tomato fruit development.Understanding factors influencing CA metabolism is essential for enhancing fruit flavor and CA-mediated biological processes.The accumulation of CA,however,is influenced by a complex interplay of genetic and environmental factors,leading to challenges in accurately predicting and regulating its levels.In this study,we conducted a genome-wide association study(GWAS)on CA,employing six landmark models based on genome-wide variations including structural variants,insertions and deletions,and single nucleotide polymorphisms.The identification of 11 high-confidence candidate genes was further facilitated by leveraging linkage disequilibrium and causal variants associated with CA.The transcriptome data from candidate genes were examined,revealing higher correlations between the expression of certain candidate genes and changes in CA metabolism.Three CA-associated genes exerted a positive regulatory effect on CA accumulation,while the remaining genes exhibited negative impacts based on gene cluster and correlation analyses.The CA content of tomatoes is primarily influenced by improvement sweeps with minimal influence from domestication sweeps in the long-term breeding history,as evidenced by population differentiation and variants distribution.The presence of various causal variants within candidate genes is implicated in the heterogeneity of CA content observed among the tomato accessions.This observation suggests a potential correlation between the number of alternative alleles and CA content.This study offers significant function-based markers that can be utilized in marker-assisted breeding,thereby enhancing their value and applicability.
Kun LiRuihong ChenAyimaiti AbudoukayoumuQian Wei...
137-148页
查看更多>>摘要：Chinese jujube(Ziziphus jujuba Mill.)is one of the most important deciduous tree fruits in China,with substantial economic and nutritional value.Jujube was domesticated from its wild progenitor,wild jujube(Z.jujuba var.spinosa),and both have high medicinal value.Here we report the 767.81-and 759.24-Mb haplotype-resolved assemblies of a dry-eating'Junzao'jujube(JZ)and a wild jujube accession(SZ),using a combination of multiple sequencing strategies.Each assembly yielded two complete haplotype-resolved genomes at the telomere-to-telomere(T2T)level,and～81.60 and 69.07 Mb of structural variations were found between the two haplotypes within JZ and SZ,respectively.Comparative genomic analysis revealed a large inversion on each of chromosomes 3 and 4 between JZ and SZ,and numerous genes were affected by structural variations,some of which were associated with starch and sucrose metabolism.A large-scale population analysis of 672 accessions revealed that wild jujube originated from the lower reaches of the Yellow River and was initially domesticated at local sites.It spread widely and was then independently domesticated at the Shanxi-Shaanxi Gorge of the middle Yellow River.In addition,we identified some new selection signals regions on genomes,which are involved in the tissue development,pollination,and other aspects of jujube tree morphology and fertilization domestication.In conclusion,our study provides high-quality reference genomes of jujube and wild jujube and new insights into the domestication history of jujube.
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