日前，上海交通大学张大兵教授指导的博士生张铮和北京师范大学任海云教授指导的博士生张毅等在水稻形态建成及植物细胞骨架调节机制研究上获得新发现。该项研究找到了一个影响水稻生长发育的formin基因——FH5/RMD，审稿人认为这是被子植物研究领域中第一次揭示单个formin基因突变可对植物营养生长和生殖生长产生严重影响，产生异常的根、茎、叶、花和种子等。细胞学和生物化学等试验证明该Formin蛋白可同时调控细胞骨架（微管和微丝）的结构，从而控制植物细胞形态和器官建成。该研究为阐明细胞骨架在植物生长发育的作用提供了依据，并对今后植物细胞骨架和形态建成研究提供了借鉴。该论文2011年2月9日在植物分子生物学领域的著名刊物《The Plant Cell》 上在线发表（）。

论文摘要：

Multicellular organisms contain a large number of formins; however, their physiological roles in plants remain poorly understood. Here, we reveal that formin homology 5 (FH5), a type II formin mutated in rice morphology determinant (rmd), plays a crucial role in determining rice (Oryza sativa) morphology. FH5/RMD encodes a formin-like protein consisting of an N-terminal phosphatase tensin (PTEN)-like domain, an FH1 domain, and an FH2 domain. The rmd mutants display a bending growth pattern in seedlings, are stunted as adult plants, and have aberrant inflorescence (panicle) and seed shape. Cytological analysis showed that rmd mutants have severe cell elongation defects and abnormal microtubule and microfilament arrays. FH5/RMD is ubiquitously expressed in rice tissues, and its protein localization to the chloroplast surface is mediated by the PTEN domain. Biochemical assays demonstrated that recombinant FH5 protein can nucleate actin polymerization from monomeric G-actin or actin/profilin complexes, cap the barbed end of actin filaments, and bundle actin filaments in vitro. Moreover, FH5 can directly bind to and bundle microtubules through its FH2 domain in vitro. Our findings suggest that the rice formin protein FH5 plays a critical role in determining plant morphology by regulating actin dynamics and proper spatial organization of microtubules and microfilaments.

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