College of Life Science, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, 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, China.
Plant Cell. 2021 Jul 2;33(5):1530-1553. doi: 10.1093/plcell/koab056.
The coordinated development of sporophytic and gametophytic tissues is essential for proper ovule patterning and fertility. However, the mechanisms regulating their integrated development remain poorly understood. Here, we report that the Swi2/Snf2-Related1 (SWR1) chromatin-remodeling complex acts with the ERECTA receptor kinase-signaling pathway to control female gametophyte and integument growth in Arabidopsis thaliana by inhibiting transcription of the microRNA gene MIR398c in early-stage megagametogenesis. Moreover, pri-miR398c is transcribed in the female gametophyte but is then translocated to and processed in the ovule sporophytic tissues. Together, SWR1 and ERECTA also activate ARGONAUTE10 (AGO10) expression in the chalaza; AGO10 sequesters miR398, thereby ensuring the expression of three AGAMOUS-LIKE (AGL) genes (AGL51, AGL52, and AGL78) in the female gametophyte. In the context of sexual organ morphogenesis, these findings suggest that the spatiotemporal control of miRNA biogenesis, resulting from coordination between chromatin remodeling and cell signaling, is essential for proper ovule development in Arabidopsis.
雌雄配子体组织的协调发育对于正常胚珠模式和育性至关重要。然而，调节它们综合发育的机制仍知之甚少。在这里，我们报告说 Swi2/Snf2-相关 1（SWR1）染色质重塑复合物与 ERECTA 受体激酶信号通路协同作用，通过抑制早期大配子体发生中 microRNA 基因 MIR398c 的转录，控制拟南芥的雌性配子体和珠被的生长。此外，pri-miR398c 在雌性配子体中转录，但随后易位到胚珠的孢子体组织中并进行加工。SWR1 和 ERECTA 还共同在合点处激活 ARGONAUTE10（AGO10）的表达；AGO10 可结合 miR398，从而确保三个 AGAMOUS-LIKE（AGL）基因（AGL51、AGL52 和 AGL78）在雌性配子体中的表达。在性器官形态发生的背景下，这些发现表明，由于染色质重塑和细胞信号之间的协调，miRNA 生物发生的时空调控对于拟南芥中正常胚珠发育是必不可少的。
