【摘要】 叶球是大白菜的主要商品器官，叶片生长是决定叶球形态建成的决定因素，其机制的解析为大白菜分子设计育种提供重要理论支撑。本研究从甲基磺酸乙酯（EMS）诱变突变体库中筛选获得2份小株型突变体mini9和mini135。表型分析显示，2份突变体株高、株展、叶长和叶宽均显著小于野生型。转录组测序和qRTPCR结果表明，相较于野生型，2份突变体中生长素信号早期响应基因IAA19和SAUR34的表达水平显著下调。植物内源激素检测结果表明，2份突变体中生长素组分吲哚-3-羧酸（ICA）的含量相较于野生型显著升高，而吲哚-3-丙酸（IPA）水平显著降低。进一步研究表明，ICA的积累与IPA的减少可能抑制了IAA19与SAUR34的表达，进而影响叶片的发育，为深入解析大白菜叶片发育机制及叶球形态建成奠定了理论基础。更多还原

【Abstract】 The leafy head is the primary commercial organ of Chinese cabbage(Brassica rapa ssp. pekinensis), and leaf growth determines heading formation. Deciphering its regulatory mechanisms provides crucial theoretical support for molecular design breeding in this crop. In this study, we identified two dwarf mutants, mini9 and mini135, from an ethyl methanesulfonate(EMS)-mutagenized population. Phenotypic analysis revealed significantly reduced plant height, spread, leaf length, and width in both mutants compared with the WT. Results of transcriptome sequencing and qRT-PCR demonstrated substantial downregulation of the auxin early responsive genes IAA19 and SAUR34 in both mutants. Endogenous hormone quantification showed significantly elevated indole-3-carboxylic acid(ICA) levels but reduced indole-3-propionic acid(IPA) content. Further analysis suggested that accumulated ICA and diminished IPA may suppress IAA19 and SAUR34 expression, thereby impairing leaf development. This work lays a foundation for deciphering leaf development mechanisms and heading morphogenesis in Chinese cabbage.更多还原