College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China.
Rice Research Institute, Shenyang Agricultural University, Shenyang, 110866, China.
Plant Physiol. 2023 Jan 2;191(1):280-298. doi: 10.1093/plphys/kiac427.
Plant height and tiller number are two major factors determining plant architecture and yield. However, in rice (Oryza sativa), the regulatory mechanism of plant architecture remains to be elucidated. Here, we reported a recessive rice mutant presenting dwarf and reduced tillering phenotypes (drt1). Map-based cloning revealed that the phenotypes are caused by a single point mutation in DRT1, which encodes the Class I formin protein O. sativa formin homolog 13 (OsFH13), binds with F-actin, and promotes actin polymerization for microfilament organization. DRT1 protein localized on the plasma membrane (PM) and chloroplast (CP) outer envelope. DRT1 interacted with rice phototropin 2 (OsPHOT2), and the interaction was interrupted in drt1. Upon blue light stimulus, PM localized DRT1 and OsPHOT2 were translocated onto the CP membrane. Moreover, deficiency of DRT1 reduced OsPHOT2 internalization and OsPHOT2-mediated CP relocation. Our study suggests that rice formin protein DRT1/OsFH13 is necessary for plant morphology and CP relocation by modulating the actin-associated cytoskeleton network.
株高和分蘖数是决定植物形态和产量的两个主要因素。然而，在水稻（Oryza sativa）中，其形态结构的调控机制仍有待阐明。在这里，我们报道了一个隐性水稻突变体，表现出矮化和分蘖减少的表型（drt1）。图位克隆表明，该表型是由 DRT1 中的一个单点突变引起的，该突变编码 I 类formin 蛋白 O. sativa formin 同源物 13（OsFH13），与 F-肌动蛋白结合，并促进肌动蛋白聚合以进行微丝组织。DRT1 蛋白定位于质膜（PM）和叶绿体（CP）外被膜上。DRT1 与水稻光受体 2（OsPHOT2）相互作用，而在 drt1 中这种相互作用被打断。在蓝光刺激下，PM 定位的 DRT1 和 OsPHOT2 被转移到 CP 膜上。此外，DRT1 的缺失减少了 OsPHOT2 的内化和 OsPHOT2 介导的 CP 重定位。我们的研究表明，水稻formin 蛋白 DRT1/OsFH13 通过调节与肌动蛋白相关的细胞骨架网络，对植物形态和 CP 重定位是必需的。
