OsmiR396d-Regulated OsGRFs Function in Floral Organogenesis in Rice through Binding to Their Targets OsJMJ706 and OsCR4
OsmiR396d-Regulated OsGRFs Function in Floral Organogenesis in Rice through Binding to Their Targets OsJMJ706 and OsCR4
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OsmiR396d 调控的 OsGRF 通过与其靶标 OsJMJ706 和 OsCR4 结合在水稻花器官发生中发挥作用
DOI：
10.1104/pp.114.235564
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发表时间：
2014-05-01
期刊：
影响因子：
7.4
通讯作者：
Chong, Kang
中科院分区：
文献类型：
--
作者：
Liu, Huanhuan;Guo, Siyi;Chong, Kang
花序和小穗发育决定谷物产量。虽然已知有多个基因参与花器官发生的调控，但在谷物中潜在的分子网络仍不清楚。在此，我们报道了水稻（Oryza sativa） microRNA396d （OsmiR396d）及其Os生长调节因子（OsGRF）靶点，以及Os生长调节因子相互作用因子1 (OsGIF1)，通过水稻JMJD2家族jmjC基因706 （OsJMJ706）和crinkly4受体样激酶（OsCR4）参与花器官发育调控。OsmiR396d的预测靶点OsGRF6转基因敲低系和OsmiR396d过表达系在花器官发育方面表现出相似的缺陷，包括开放的外壳、长不育的外稃和花器官形态的改变。过表达OsGRF6几乎完全修复了这些缺陷。OsGRF6及其同源物OsGRF10是OsGRF家族成员中年轻花序中表达量最高的，并且grf6/grf10双突变体表现出异常小花。OsGRF6/OsGRF10定位于细胞核，电泳迁移转移实验显示，OsGRF6和OsGRF10都结合了OsJMJ706和OsCR4启动子中的GA响应元件，而OsJMJ706和OsCR4启动子曾被报道参与花器官发育的调控。此外，OsGRF6和OsGRF10可以反激活OsJMJ706和OsCR4，该活性在OsGIF1存在时增强，OsGRF6和OsGRF10都可以结合。综上所述，我们的研究结果表明，OsmiR396d通过靶向JMJ706和OsCR4调控OsGRF基因的表达，OsGRF基因在小花发育过程中与OsGIF1一起发挥作用。本研究揭示了水稻小穗发育调控的microrna介导的调控模块。
Inflorescence and spikelet development determine grain yields in cereals. Although multiple genes are known to be involved in the regulation of floral organogenesis, the underlying molecular network remains unclear in cereals. Here, we report that the rice (Oryza sativa) microRNA396d (OsmiR396d) and its Os Growth Regulating Factor (OsGRF) targets, together with Os Growth Regulating Factor-Interacting Factor1 (OsGIF1), are involved in the regulation of floral organ development through the rice JMJD2 family jmjC gene 706 (OsJMJ706) and crinkly4 receptor-like kinase (OsCR4). Transgenic knockdown lines of OsGRF6, a predicted target of OsmiR396d, and overexpression lines of OsmiR396d showed similar defects in floral organ development, including open husks, long sterile lemmas, and altered floral organ morphology. These defects were almost completely rescued by overexpression of OsGRF6. OsGRF6 and its ortholog OsGRF10 were the most highly expressed OsGRF family members in young inflorescences, and the grf6/grf10 double mutant displayed abnormal florets. OsGRF6/OsGRF10 localized to the nucleus, and electrophoretic mobility shift assays revealed that both OsGRF6 and OsGRF10 bind the GA response element in the promoters of OsJMJ706 and OsCR4, which were reported to participate in the regulation of floral organ development. In addition, OsGRF6 and OsGRF10 could transactivate OsJMJ706 and OsCR4, an activity that was enhanced in the presence of OsGIF1, which can bind both OsGRF6 and OsGRF10. Together, our results suggest that OsmiR396d regulates the expression of OsGRF genes, which function with OsGIF1 in floret development through targeting of JMJ706 and OsCR4. This work thus reveals a microRNA-mediated regulation module for controlling spikelet development in rice.