植物学报 ›› 2025, Vol. 60 ›› Issue (4): 515-532.DOI: 10.11983/CBB24112  cstr: 32102.14.CBB24112

• 研究论文 • 上一篇    下一篇

一个新的黄瓜叶色突变体鉴定、初定位及转录组分析

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*()   

  1. 湖南农业大学生物科学技术学院, 植物激素与生长发育湖南省重点实验室, 长沙 410128
  • 收稿日期:2024-07-23 接受日期:2025-06-04 出版日期:2025-07-10 发布日期:2025-06-04
  • 通讯作者: 萧浪涛,王若仲
  • 基金资助:
    湖南省教育厅科技计划(20B306)

Identification, Mapping and Transcriptome Analysis of a New Leaf Color Mutant in Cucumber

Manya Zhao, Qiannan Sun, Jingjing Xu, Tianni Duan, Jintao Cai, Jing Zhou, Tingting Fan, Langtao Xiao*(), Ruozhong Wang*()   

  1. Hunan Provincial Key Laboratory of Phytohormones and Growth Development, College of Bioscience and Biotechnology Hunan Agricultural University, Changsha 410128, China
  • Received:2024-07-23 Accepted:2025-06-04 Online:2025-07-10 Published:2025-06-04
  • Contact: Langtao Xiao, Ruozhong Wang

摘要: 叶色突变体是研究光形态发生、叶绿体发育、叶绿素代谢和光合作用机制等多种生理过程的理想材料。该研究从黄瓜(Cucumis sativus) XYYH-2-1-1株系自交后代中获得1个新的黄化致死突变体ycl (yellow cotyledon lethal)。该突变体自幼苗出土后子叶一直呈黄化状态, 约2周后枯萎死亡, 其生长抑制表型为非光依赖型。与野生型相比, ycl突变体的Chl a和Chl b含量趋于零, 叶绿素生物合成途径中Mg2+螯合过程受阻。显微和超微结构分析发现, ycl叶片组织紊乱、叶绿体发育受阻。ycl的抗氧化酶活性及丙二醛含量显著升高, 说明其受到氧化胁迫, 且抗氧化能力强。ycl净光合速率极显著降低, 胞间CO2浓度上升, 推测ycl光合速率降低源于气孔导度降低、叶绿素含量减少和叶绿体发育受阻。转录组学分析表明, ycl与其野生型间存在337个差异表达基因, 光合作用、类黄酮生物合成、叶绿素代谢和活性氧代谢是导致ycl黄化致死表型形成的关键途径。通过BSA-Seq分析, ycl突变基因初步定位于3号染色体的1.48-1.9 Mb区间, 内含41个候选基因。对ycl突变体的研究为阐明黄瓜叶绿体发育的分子机制提供了参考。

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

Abstract: INTRODUCTION Cucumber (Cucumis sativus) is one of the foremost vegetable crops globally. Photosynthesis intricately 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 photomorphogenesis, 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 further investigation into the molecular mechanisms responsible for the lethal phenotype associated with yclyellowing. 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 accumulated extremely low Chl a and Chl b contents, which was consistent with the blockade in the magnesium ion chelation 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 chloroplast 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 yclmutant, 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 molecular mechanisms of chloroplast development in cucumber.
Phenotypic changes of WT and the ycl mutant at the cotyledon stage under natural light conditions, and preliminary mapping of the mutant gene.

Key words: cucumber, yellowing lethal mutant ycl, physiological characteristics, gene mapping, transcriptome analysis