The random amplified polymorphic DNA （RAPD） marker was assessed to detect the genetic relationships among 48 hybrid Cymbidium cultivars from Japan, Korea, China, and USA, and 2 species of native Cymbidium. Twenty pr...The random amplified polymorphic DNA （RAPD） marker was assessed to detect the genetic relationships among 48 hybrid Cymbidium cultivars from Japan, Korea, China, and USA, and 2 species of native Cymbidium. Twenty primers were screened from 100 random decamer primers, and a total of 258 DNA bands were amplified, 253 of which （98.1%） were polymorphic. The average number of polymorphic DNA bands amplified by each primer was 12.6. All cultivars were distinguishable when a number of primers were considered. Genetic similarities among the cultivars and species were estimated based on the amount of band sharing ranging from 0.364-0.817 with an average of 0.581. According to the data, a dendrogram of genetic relationship, which was constructed using the UPGMA method, showed that all the tested cultivars and native species were classified into five cluster groups with the similarity coefficient of 0.592. It revealed that the genetic relationships among tested accessions were to some extent related with their origin, flower colour, branch type, and genealogy. It further indicated that the RAPD technique is a useful tool for studying the genetic relationships among hybrid Cymbidium cultivars.展开更多
The floral morphology of Cymbidium ensifolium,a well-known orchid in China,has increasingly attracted horticultural and commercial attention.However,the molecular mechanisms that regulate flower development defects in...The floral morphology of Cymbidium ensifolium,a well-known orchid in China,has increasingly attracted horticultural and commercial attention.However,the molecular mechanisms that regulate flower development defects in C.ensifolium mutants are poorly understood.In this work,we examined a domesticated variety of C.ensifolium named‘CuiYuMuDan',or leaf-like flower mutant,which lacks typical characteristics of orchid floral organs but continues to produce sepal-to leaf-like structures along the inflorescence.We used comparative transcriptome analysis to identify 6234 genes that are differentially expressed between mutant and wild-type flowers.The majority of these differentially expre ssed genes are involved in membrane-building,anabolism regulation,and plant hormone signal transduction,implying that in the leaf-like mutant these processes play roles in the development of flower defects.In addition,we identified 152 differentially expre ssed transcription factors,including the bHLH,MYB,MIKC,and WRKY gene families.Moreover,we found 20 differentially expressed genes that are commonly involved in flower development,including MADS-box genes,CLAVATA3(CLV3),WUSCHEL(WUS),and PERIANTHIA(PAN).Among them,floral homeotic genes were further investigated by phylogenetic analysis and expression validation,which displayed distinctive spatial expression patterns and significant changes between the wild type and the mutant.This is the first report on the C.ensifolium leaf-like flower mutant transcriptome.Our results shed light on the molecular regulation of orchid flower development,and may improve our understanding of floral patterning regulation and advance molecular breeding of Chinese orchids.展开更多
Cymbidium,which includes approximately 80 species,is one of the most ornamental and cultivated orchid genera.However,a lack of markers and sparse sampling have posed great challenges to resolving the phylogenetic rela...Cymbidium,which includes approximately 80 species,is one of the most ornamental and cultivated orchid genera.However,a lack of markers and sparse sampling have posed great challenges to resolving the phylogenetic relationships within the genus.In the present study,we reconstructed the phylogenetic relationships by utilizing one nuclear DNA(nrITS)and seven plastid genes(rbcL,trnS,trnG,matK,trnL,psbA,and atpI)from 70 species(varieties)in Cymbidium.We also examined the occurrence of phylogenetic conflict between nuclear(nrITS)and plastid loci and investigated how phylogenetic conflict bears on taxonomic classification within the genus.We found that phylogenetic conflict and low support values may be explained by hybridization and a lack of informative characteristics.Our results do not support previous classification of the subgenera and sections within Cymbidium.Discordance between gene trees and network analysis indicate that reticulate evolution occurred in the genus Cymbidium.Overall,our study indicates that Cymbidium has undergone a complex evolution.展开更多
文摘The random amplified polymorphic DNA （RAPD） marker was assessed to detect the genetic relationships among 48 hybrid Cymbidium cultivars from Japan, Korea, China, and USA, and 2 species of native Cymbidium. Twenty primers were screened from 100 random decamer primers, and a total of 258 DNA bands were amplified, 253 of which （98.1%） were polymorphic. The average number of polymorphic DNA bands amplified by each primer was 12.6. All cultivars were distinguishable when a number of primers were considered. Genetic similarities among the cultivars and species were estimated based on the amount of band sharing ranging from 0.364-0.817 with an average of 0.581. According to the data, a dendrogram of genetic relationship, which was constructed using the UPGMA method, showed that all the tested cultivars and native species were classified into five cluster groups with the similarity coefficient of 0.592. It revealed that the genetic relationships among tested accessions were to some extent related with their origin, flower colour, branch type, and genealogy. It further indicated that the RAPD technique is a useful tool for studying the genetic relationships among hybrid Cymbidium cultivars.
基金grants from National Key R&D Program(2018YFD1000404)the National Natural Science Foundation of China(31672184)+3 种基金the Natural Science Foundation of Guangdong Province(2017A030312004)Guangzhou Science and Technology Project(201707010307,201904020026)Innovation Team of Modern Agricultural Industry Technology System in Guangdong Province(2019KJ121)the Guangdong Academy of Agricultural Sciences Discipline Team Construction Project(201612TD,2017A070702008,201721).
文摘The floral morphology of Cymbidium ensifolium,a well-known orchid in China,has increasingly attracted horticultural and commercial attention.However,the molecular mechanisms that regulate flower development defects in C.ensifolium mutants are poorly understood.In this work,we examined a domesticated variety of C.ensifolium named‘CuiYuMuDan',or leaf-like flower mutant,which lacks typical characteristics of orchid floral organs but continues to produce sepal-to leaf-like structures along the inflorescence.We used comparative transcriptome analysis to identify 6234 genes that are differentially expressed between mutant and wild-type flowers.The majority of these differentially expre ssed genes are involved in membrane-building,anabolism regulation,and plant hormone signal transduction,implying that in the leaf-like mutant these processes play roles in the development of flower defects.In addition,we identified 152 differentially expre ssed transcription factors,including the bHLH,MYB,MIKC,and WRKY gene families.Moreover,we found 20 differentially expressed genes that are commonly involved in flower development,including MADS-box genes,CLAVATA3(CLV3),WUSCHEL(WUS),and PERIANTHIA(PAN).Among them,floral homeotic genes were further investigated by phylogenetic analysis and expression validation,which displayed distinctive spatial expression patterns and significant changes between the wild type and the mutant.This is the first report on the C.ensifolium leaf-like flower mutant transcriptome.Our results shed light on the molecular regulation of orchid flower development,and may improve our understanding of floral patterning regulation and advance molecular breeding of Chinese orchids.
基金funded by The National Key Research and Development Program of China(Nos.2018YFD1000401 and 2018YFD1000400)the Natural Science Foundation of Guangdong Province(No.2017A030312004)the Science and Technology Plan Project of Shenzhen(No.JCYJ20170817151501595).
文摘Cymbidium,which includes approximately 80 species,is one of the most ornamental and cultivated orchid genera.However,a lack of markers and sparse sampling have posed great challenges to resolving the phylogenetic relationships within the genus.In the present study,we reconstructed the phylogenetic relationships by utilizing one nuclear DNA(nrITS)and seven plastid genes(rbcL,trnS,trnG,matK,trnL,psbA,and atpI)from 70 species(varieties)in Cymbidium.We also examined the occurrence of phylogenetic conflict between nuclear(nrITS)and plastid loci and investigated how phylogenetic conflict bears on taxonomic classification within the genus.We found that phylogenetic conflict and low support values may be explained by hybridization and a lack of informative characteristics.Our results do not support previous classification of the subgenera and sections within Cymbidium.Discordance between gene trees and network analysis indicate that reticulate evolution occurred in the genus Cymbidium.Overall,our study indicates that Cymbidium has undergone a complex evolution.
