植物学报2025，Vol.60Issue(4)：515-532,18.DOI:10.11983/CBB24112
一个新的黄瓜叶色突变体鉴定、初定位及转录组分析
Identification,Mapping and Transcriptome Analysis of a New Leaf Color Mutant in Cucumber
摘要
Abstract
INTRODUCTION:Cucumber(Cucumis sativus)is one of the foremost vegetable crops globally.Photosynthesis intri-cately influences the fruit yield of cucumber,and leaf color determines the photosynthetic efficiency to a large extent.Therefore,Leaf color mutants serve as ideal materials for scrutinizing diverse physiological processes,including pho-tomorphogenesis,chloroplast development,chlorophyll metabolism,and photosynthetic mechanisms.Currently,the molecular mechanisms underlying the yellowing lethal phenotype remain unclear. RATIONALE:In this study,a stable cucumber yellowing lethal mutant,ycl(yellow cotyledon lethal),was isolated from the near-isogenic line XYYH-2-1-1.The phenotype,leaf microstructure and chloroplast ultrastructure,as well as physiological and biochemical analyses,were conducted on the mutant ycl and the wild-type XYYH-3-1 to explore the physiological mechanisms underlying the yellowing lethal phenotype.Preliminary localisation of yellowing lethal mutation genes was performed by whole genome resequencing using BSA.The integration of transcriptome sequencing allowed us to analyze the expression of genes related to yellowing death and the main pathways.This approach laid a solid foundation for fur-ther investigation into the molecular mechanisms responsible for the lethal phenotype associated with ycl yellowing. RESULTS:The ycl mutant exhibited yellow cotyledons,which ultimately withered and perished within approximately two weeks.Notably,its growth-inhibiting phenotype appeared to be light-independent.Compared to the wild type,ycl ac-cumulated extremely low Chl a and Chl b contents,which was consistent with the blockade in the magnesium ion che-lation process within the chlorophyll biosynthesis pathway.Microscopic and ultrastructural analyses revealed disordered ycl leaf structure and inhibited chloroplast development.Additionally,the ycl mutant displayed significantly increased antioxidant enzyme activities and malondialdehyde contents,suggesting elevated oxidative stress levels and robust antioxidant capacities.The substantial decrease in net photosynthetic rate and rise in intercellular CO2 concentration in ycl were hypothesized to stem from reduced stomatal conductance,diminished chlorophyll content,and impaired chlo-roplast development in the mutant.Transcriptomic analyses suggested that key pathways including photosynthesis,flavonoid biosynthesis,chlorophyll metabolism,and reactive oxygen species metabolism were affected in ycl.The ycl mutant gene was preliminarily mapped to a region between 1.48 to 1.9 Mb on chromosome 3 through BSA-seq analysis,encompassing 41 candidate genes. CONCLUSION:The study investigated the physiological mechanisms underlying the yellowing lethal phenotype of the ycl mutant,preliminarily mapped the mutant gene to chromosome 3,and identified differentially expressed genes(DEGs)and key pathways associated with the lethal phenotype.These findings provide valuable insights into the mo-lecular mechanisms of chloroplast development in cucumber.关键词
黄瓜/黄化致死突变体ycl/生理特性/基因定位/转录组分析Key words
cucumber/yellowing lethal mutant ycl/physiological characteristics/gene mapping/transcriptome analysis引用本文复制引用
赵蔓雅,孙倩楠,徐晶晶,段恬妮,蔡锦涛,周婧,范婷婷,萧浪涛,王若仲..一个新的黄瓜叶色突变体鉴定、初定位及转录组分析[J].植物学报,2025,60(4):515-532,18.基金项目
湖南省教育厅科技计划(No.20B306) （No.20B306）
