Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fujian, 350002, Fuzhou, China.
The Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan, 430074, Hubei, China.
BMC Genomics. 2022 Jan 5;23(1):8. doi: 10.1186/s12864-021-08197-7.
The pistil is an essential part of flowers that functions in the differentiation of the sexes and reproduction in plants. The stigma on the pistil can accept pollen to allow fertilization and seed development. Papaya (Carica papaya L.) is a dioecious plant, where female flowers exhibit normal pistil, while the male flowers exhibit aborted pistil at a late stage of pistil development.
The developmental stages of papaya pistil were analyzed after first dividing it into slices representing the primordium stage 1 (S1), the pre-meiotic stages S2, post-meiotic stage S3, and the mitotic stage S4. The SS scoring algorithm analysis of genes preferentially expressed at different stages revealed differentially expressed genes between male and female flowers. A transcription factor regulatory network for each stage based on the genes that are differentially expressed between male and female flowers was constructed. Some transcription factors related to pistil development were revealed based on the analysis of regulatory networks such as CpAGL11, CpHEC2, and CpSUPL. Based on the specific expression of genes, constructed a gene regulatory subnetwork with CpAGL11-CpSUPL-CpHEC2 functioning as the core. Analysis of the functionally enriched terms in this network reveals several differentially expressed genes related to auxin/ brassinosteroid signal transduction in the plant hormone signal transduction pathway. At the same time, significant differences in the expression of auxin and brassinosteroid synthesis-related genes between male and female flowers at different developmental stages were detected.
The pistil abortion of papaya might be caused by the lack of expression or decreased expression of some transcription factors and hormone-related genes, affecting hormone signal transduction or hormone biosynthesis. Analysis of aborted and normally developing pistil in papaya provided new insights into the molecular mechanism of pistil development and sex differentiation in dioecious papaya.
雌蕊是花的重要组成部分，在植物的性别分化和繁殖中起作用。雌蕊柱头上可以接受花粉，从而允许受精和种子发育。木瓜（Carica papaya L.）是一种雌雄异株的植物，其中雌花具有正常的雌蕊，而雄花在雌蕊发育的后期表现出败育的雌蕊。
对木瓜雌蕊的发育阶段进行了分析，首先将其划分为代表原基期 1（S1）、减数前期 S2、减数后期 S3 和有丝分裂期 S4 的切片。根据不同阶段基因的 SS 评分算法分析，揭示了雄花和雌花之间差异表达的基因。基于雄花和雌花之间差异表达的基因，构建了每个阶段的转录因子调控网络。根据调控网络分析，发现了一些与雌蕊发育相关的转录因子，如 CpAGL11、CpHEC2 和 CpSUPL。基于基因的特异性表达，构建了一个以 CpAGL11-CpSUPL-CpHEC2 为核心的基因调控子网络。对该网络中功能丰富术语的分析揭示了植物激素信号转导途径中与生长素/油菜素信号转导相关的几个差异表达基因。同时，在不同发育阶段，雄花和雌花之间生长素和油菜素合成相关基因的表达存在显著差异。
木瓜雌蕊败育可能是由于某些转录因子和激素相关基因的表达缺失或下调，影响激素信号转导或激素生物合成所致。对木瓜败育和正常发育雌蕊的分析为雌雄异株木瓜雌蕊发育和性别分化的分子机制提供了新的见解。
