查看更多>>摘要：Apricot,belonging to the Armeniaca section of Rosaceae,is one of the economically important crop fruits that has been extensively cultivated.The natural wild apricots offer valuable genetic resources for crop improvement.However,some of them are endemic,with small populations,and are even at risk of extinction.In this study we unveil chromosome-level genome assemblies for two southern China endemic apricots,Prunus hongpingensis(PHP)and P.zhengheensis(PZH).We also characterize their evolutionary history and the genomic basis of their local adaptation using whole-genome resequencing data.Our findings reveal that PHP and PZH are closely related to Prunus armeniaca and form a distinct lineage.Both species experienced a decline in effective population size following the Last Glacial Maximum(LGM),which likely contributed to their current small population sizes.Despite the observed decrease in genetic diversity and heterozygosity,we do not observe an increased accumulation of deleterious mutations in these two endemic apricots.This is likely due to the combined effects of a low inbreeding coefficient and strong purifying selection.Furthermore,we identify a set of genes that have undergone positive selection and are associated with local environmental adaptation in PHP and PZH,respectively.These candidate genes can serve as valuable genetic resources for targeted breeding and improvement of cultivated apricots.Overall,our study not only enriches our comprehension of the evolutionary history of apricot species but also offers crucial insights for the conservation and future breeding of other endemic species amidst rapid climate changes.
查看更多>>摘要：Flowering is one of the most important biological phenomena in the plant kingdom,which not only has important ecological significance,but also has substantial horticultural ornamental value.In this study,we undertook an exhaustive review of the advancements in our understanding of plant flowering genes.We delved into the identification and conducted comparative analyses of flowering genes across virtually all sequenced angiosperm plant genomes.Furthermore,we established an extensive angiosperm flowering atlas,encompassing a staggering 183 720 genes across eight pathways,along with 10155 ABCDE mode genes,which play a pivotal role in plant flowering regulation.Through the examination of expression patterns,we unveiled the specificities of these flowering genes.An interaction network between flowering genes of the ABCDE model and their corresponding upstream genes offered a blueprint for comprehending their regulatory mechanisms.Moreover,we predicted the miRNA and target genes linked to the flowering processes of each species.To culminate our efforts,we have built a user-friendly web interface,named the Plant Flowering-time Gene Database(PFGD),accessible at http://pfgd.bio2db.com/.We firmly believe that this database will serve as a cornerstone in the global research community,facilitating the in-depth exploration of flowering genes in the plant kingdom.In summation,this pioneering endeavor represents the first comprehensive collection and comparative analysis of flowering genes in plants,offering valuable resources for the study of plant flowering genetics.
查看更多>>摘要：ABSCISIC ACID-INSENSITIVE5(ABI5)is a core regulatory factor that mediates the ABA signaling response and leaf senescence.However,the molecular mechanism underlying the synergistic regulation of leaf senescence by ABI5 with interacting partners and the homeostasis of ABI5 in the ABA signaling response remain to be further investigated.In this study,we found that the accelerated effect of MdABI5 on leaf senescence is partly dependent on MdbHLH93,an activator of leaf senescence in apple.MdABI5 directly interacted with MdbHLH93 and improved the transcriptional activation of the senescence-associated gene MdSAG18 by MdbHLH93.MdPUB23,a U-box E3 ubiquitin ligase,physically interacted with MdABI5 and delayed ABA-triggered leaf senescence.Genetic and biochemical analyses suggest that MdPUB23 inhibited MdABI5-promoted leaf premature senescence by targeting MdABI5 for ubiquitin-dependent degradation.In conclusion,our results verify that MdABI5 accelerates leaf senescence through the MdABI5-MdbHLH93-MdSAG18 regulatory module,and MdPUB23 is responsible for the dynamic regulation of ABA-triggered leaf senescence by modulating the homeostasis of MdABI5.
查看更多>>摘要：Chromosomal inversion is an important structural variation that usually suppresses recombination and is critical for key genotype fixation.In a previous study,an 11.47 Mb recombination suppression region was identified in the yellow-green leaf locus BoYgl-1 on chromosome 1,but the cause of recombination suppression is still unclear.In this study,chlorophyll and carotenoid contents were found to be significantly decreased in the yellow-green leaf mutant YL-1.Genome assembly and comparative analysis revealed that two large inversions in YL-1 were responsible for the severe recombination suppression in the BoYgl-1 locus.Analyses with inversion-specific markers revealed that the inversions were present in 44(including all wild cabbage;INV1 and INV2)of 195 cabbage inbred lines and 15(INV1)ornamental kale inbred lines,indicating that these species with INV1 or INV2 may have evolved much earlier than other types of cabbage.Analyses with inversion-correlated markers revealed that the genotypes of CoINV1,CoINV2 and CoINV3 were highly correlated with INV1 and INV2,indicating that INVs could fix the key genotypes of the involved region.In addition,a 5.87 Mb assembly inversion was identified at the BoYgl-1 locus in the TO1000 genome by genome comparative analysis.This study provides new insight into the recombination suppression mechanism of chromosomal inversion and the application of genome fragment fixation in cabbage breeding.
查看更多>>摘要：Transcription factors with basic helix-loop-helix(bHLH)structures regulate plant growth,epidermal structure development,metabolic processes,and responses to stress extensively.Sea lavender(Limonium bicolor)is a recretohalophyte with unique salt glands in the epidermis that make it highly resistant to salt stress,contributing to the improvement of saline lands.However,the features of the bHLH transcription factor family in L.bicolor are largely unknown.Here,we systematically analyzed the characteristics,localization,and phylogenetic relationships of 187 identified bHLH family genes throughout the L.bicolor genome,as well as their cis-regulatory promoter elements,expression patterns,and key roles in salt gland development or salt tolerance by genetic analysis.Nine verified L.bicolor bHLH genes are expressed and the encoded proteins function in the nucleus,among which the proteins encoded by Lb2G14060 and Lb1G07934 also localize to salt glands.Analysis of CRISPR-Cas9-generated knockout mutants and overexpression lines indicated that the protein encoded by Lb1G07934 is involved in the formation of salt glands,salt secretion,and salt resistance,indicating that bHLH genes strongly influence epidermal structure development and stress responses.The current study lays the foundation for further investigation of the effects and functional mechanisms of bHLH genes in L.bicolor and paves the way for selecting salt-tolerance genes that will enhance salt resistance in crops and for the improvement of saline soils.
查看更多>>摘要：The homoterpenes(3E)-4,8-dimethyl-1,3,7-nonatriene(DMNT)and(E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene(TMTT)are the major herbivore-induced plant volatiles that help in defense directly by acting as repellants and indirectly by recruiting insects'natural enemies.In this study,DMNT and TMTT were confirmed to be emitted from citrus(Citrus sinensis)leaves infested with Asian citrus psyllid(Diaphorina citri Kuwayama;ACP),and two cytochrome P450(CYP)genes(CsCYP82L1 and CsCYP82L2)were newly identified and characterized.Understanding the functions of these genes in citrus defense will help plan strategies to manage huanglongbing caused by Candidatus Liberibacter asiaticus(CLas)and spread by ACP.Quantitative real-time PCR(qPCR)analysis showed that CsCYP82L1 and CsCYP82L2 were significantly upregulated in citrus leaves after ACP infestation.Yeast recombinant expression and enzyme assays indicated that CsCYP82L1 and CsCYP82L2 convert(E)-nerolidol to DMNT and(E,E)-geranyllinalool to TMTT.However,citrus calluses stably overexpressing CsCYP82L1 generated only DMNT,whereas those overexpressing CsCYP82L2 produced DMNT and TMTT.Further-more,ACPs preferred wild-type lemon(Citrus limon)over the CsCYP82L1-overexpressing line in dual-choice feeding assays and mineral oil over TMTT or DMNT in behavioral bioassays.Finally,yeast one-hybrid,electrophoretic mobility shift,and dual luciferase assays demonstrated that CsERF017,an AP2/ERF transcription factor,directly bound to the CCGAC motif and activated CsCYP82L1.Moreover,the transient overexpression of CsERF017 in lemon leaves upregulated CsCYP82L1 in the absence and presence of ACP infestation.These results provide novel insights into homoterpene biosynthesis in C.sinensis and demonstrate the effect of homoterpenes on ACP behavior,laying a foundation to genetically manipulate homoterpene biosynthesis for application in huanglongbing and ACP control.
查看更多>>摘要：Cissus quadrangularis is a tetraploid species belonging to the Vitaceae family and is known for the Crassulacean acid metabolism(CAM)pathway in the succulent stem,while the leaves perform C3 photosynthesis.Here,we report a high-quality genome of C.quadrangularis comprising a total size of 679.2 Mb which was phased into two subgenomes.Genome annotation identified 51857 protein-coding genes,while approximately 47.75％of the genome was composed of repetitive sequences.Gene expression ratios of two subgenomes demonstrated that the sub-A genome as the dominant subgenome played a vital role during the drought tolerance.Genome divergence analysis suggests that the tetraploidization event occurred around 8.9 million years ago.Transcriptome data revealed that pathways related to cutin,suberine,and wax metabolism were enriched in the stem during drought treatment,suggesting that these genes contributed to the drought adaption.Additionally,a subset of CAM-related genes displayed diurnal expression patterns in the succulent stems but not in leaves,indicating that stem-biased expression of existing genes contributed to the CAM evolution.Our findings provide insights into the mechanisms of drought adaptation and photosynthesis transition in plants.
查看更多>>摘要：Chrysanthemum x morifolium has great ornamental and economic value on account of its exquisite capitulum.However,previous studies have mainly focused on the corolla morphology of the capitulum.Such an approach cannot explain the variable inflorescence architecture of the chrysanthemum.Previous research from our group has shown that NO APICAL MERISTEM(ClNAM)is likely to function as a hub gene in capitulum architecture in the early development stage.In the present study,ClNAM was used to investigate the function of these boundary genes in the capitulum architecture of Chrysanthemum lavandulifolium,a closely related species of C.x morifolium in the genus.Modification of ClNAM in C.lavandulifolium resulted in an advanced initiation of the floral primordium at the capitulum.As a result,the receptacle morphology was altered and the number of florets decreased.The ray floret corolla was shortened,but the disc floret was elongated.The number of capitula increased significantly,arranged in more densely compounded corymbose synflorescences.The yeast and luciferase reporter system revealed that ClAP1,ClRCD2,and ClLBD18 target and activate ClNAM.Subsequently,ClNAM targets and activates ClCUC2a/c,which regulates the initiation of floral and inflorescence in C.lavandulifolium.ClNAM was also targeted and cleaved by cla-miR164 in this process.In conclusion,this study established a boundary gene regulatory network with cla-miR164-ClNAM as the hub.This network not only influences the architecture of capitulum,but also affects compound corymbose synflorescences of the C.lavandulifolium.These results provide new insights into the mechanisms regulating inflorescence architecture in chrysanthemum.
查看更多>>摘要：The gaseous plant hormone ethylene regulates plant development,growth,and responses to stress.In particular,ethylene affects tolerance to salinity;however,the underlying mechanisms of ethylene signaling and salt tolerance are not fully understood.Here,we demonstrate that salt stress induces the degradation of the ethylene receptor ETHYLENE RESPONSE 3(RhETR3)in rose(Rosa hybrid).Furthermore,the TspO/MBR(Tryptophan-rich sensory protein/mitochondrial benzodiazepine receptor)domain-containing membrane protein RhTSPO interacted with RhETR3 to promote its degradation in response to salt stress.Salt tolerance is enhanced in RhETR3-silenced rose plants but decreased in RhTSPO-silenced plants.The improved salt tolerance of RhETR3-silenced rose plants is partly due to the increased expression of ACC SYNTHASE1(ACS1)and ACS2,which results in an increase in ethylene production,leading to the activation of ETHYLENE RESPONSE FACTOR98(RhERF98)expression and,ultimately accelerating H2O2 scavenging under salinity conditions.Additionally,overexpression of RhETR3 increased the salt sensitivity of rose plants.Co-overexpression with RhTSPO alleviated this sensitivity.Together,our findings suggest that RhETR3 degradation is a key intersection hub for the ethylene signalling-mediated regulation of salt stress.
查看更多>>摘要：Phenylphenalenones(PhPNs),phytoalexins in wild bananas(Musaceae),are known to act against various pathogens.However,the abundance of PhPNs in many Musaceae plants of economic importance is low.Knowledge of the biosynthesis of PhPNs and the application of biosynthetic approaches to improve their yield is vital for fighting banana diseases.However,the processes of PhPN biosynthesis,especially those involved in methylation modification,remain unclear.Musella lasiocarpa is a herbaceous plant belonging to Musaceae,and due to the abundant PhPNs,their biosynthesis in M.lasiocarpa has been the subject of much attention.In this study,we assembled a telomere-to-telomere gapless genome of M.lasiocarpa as the reference,and further integrated transcriptomic and metabolomic data to mine the candidate genes involved in PhPN biosynthesis.To elucidate the diversity of PhPNs in M.lasiocarpa,three screened O-methyltransferases(Ml01G0494,Ml04G2958,and Ml08G0855)by phylogenetic and expressional clues were subjected to in vitro enzymatic assays.The results show that the three were all novel O-methyltransferases involved in the biosynthesis of PhPN phytoalexins,among which Ml08G0855 was proved to function as a multifunctional enzyme targeting multiple hydroxyl groups in PhPN structure.Moreover,we tested the antifungal activity of PhPNs against Fusarium oxysporum and found that the methylated modification of PhPNs enhanced their antifungal activity.These findings provide valuable genetic resources in banana breeding and lay a foundation for improving disease resistance through molecular breeding.
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