Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education; Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning 530004, Guangxi, China.
Plant Physiol. 2020 Apr;182(4):2006-2024. doi: 10.1104/pp.19.01254. Epub 2020 Feb 13.
Megasporogenesis is a key step during ovule development in angiosperms, but the small number and inaccessibility of these cells have hampered molecular and genome-wide studies. Thus, many questions remain regarding the molecular basis of cell specification, differentiation, and development in the female gametophyte. Here, taking advantage of the correlation between spikelet length and ovule development in rice (), we studied the transcriptome dynamics of young ovules at three stages, the archesporial cell, the megaspore mother cell before meiosis, and the functional megaspore after meiosis, using expression profiling based on RNA sequencing. Our analysis showed that 5,274 genes were preferentially expressed in ovules during megasporogenesis as compared to ovules at the mature female gametophyte stage. Out of these, 958 (18.16%) genes were archesporial cell- and/or megaspore mother cell-preferential genes, and represent a significant enrichment of genes involved in hormone signal transduction and plant pathogen interaction pathways, as well as genes encoding transcription factors. The expression patterns of nine genes that were preferentially expressed in ovules of different developmental stages, including the () receptor-like kinase gene, were confirmed by in situ hybridization. We further characterized the loss-of-function mutant, which had an excessive number of female germline cells and an abnormal female gametophyte, suggesting that regulates germline cell specification during megasporogenesis in rice. These results expand our understanding of the molecular control of megasporogenesis in rice and contribute to the functional studies of genes involved in megasporogenesis.
大孢子发生是被子植物胚珠发育的关键步骤，但由于这些细胞数量少且难以接近，阻碍了分子和全基因组研究。因此，关于雌性配子体中细胞特化、分化和发育的分子基础仍存在许多问题。在这里，我们利用水稻小穗长度与胚珠发育之间的相关性（），在三个阶段研究了幼胚珠的转录组动态，即原孢子细胞、减数分裂前的大孢子母细胞和减数分裂后的功能大孢子，使用基于 RNA 测序的表达谱分析。我们的分析表明，与成熟雌性配子体阶段的胚珠相比，有 5274 个基因在大孢子发生过程中在胚珠中优先表达。其中，958（18.16%）个基因是原孢子细胞和/或大孢子母细胞优先表达的基因，代表了参与激素信号转导和植物病原体相互作用途径以及编码转录因子的基因的显著富集。通过原位杂交证实了九个在不同发育阶段胚珠中优先表达的基因（包括 () 受体样激酶基因）的表达模式。我们进一步表征了 功能丧失突变体，该突变体具有过多的雌性生殖细胞和异常的雌性配子体，表明 调节大孢子发生过程中的生殖细胞特化在水稻中。这些结果扩展了我们对水稻大孢子发生分子控制的理解，并有助于对涉及大孢子发生的基因的功能研究。
