上海生科院植生生態(tài)所植物分子遺傳國家重點實驗室何祖華研究組在水稻株高發(fā)育的調(diào)控研究上取得新的進展，研究成果于2月9日在線發(fā)表于植物科學研究權(quán)威期刊Plant Cell ,。
水稻株高是控制水稻產(chǎn)量的重要農(nóng)藝性狀，主要由水稻節(jié)間的伸長調(diào)節(jié),。水稻最上節(jié)間的伸長可以促進幼穗的抽出，進而開花,，授粉和灌漿,。因此，最上節(jié)間的發(fā)育是影響水稻產(chǎn)量的重要節(jié)點,。繼克隆和功能分析了水稻長節(jié)間基因ELONGATED UPPERMOST INTERNODE (Eui)后（Zhu et al., 2006,Plant Cell ）,該研究組一直致力于水稻節(jié)間發(fā)育的研究,，成功克隆了BENT UPPERMOST INTERNODE1 (BUI1)基因并系統(tǒng)闡述了BUI1蛋白的生理和生化功能。
BUI1編碼一個植物特異的Class II formin蛋白,，調(diào)控細胞微絲骨架（actin cytoskeleton）的裝配和動態(tài)變化,。微絲骨架是細胞形態(tài)和多種生理過程的基礎。BUI1的突變導致細胞中F-actin含量降低,，actin bundles數(shù)目減少,，細胞的伸長和極性擴展受到抑制。進而影響了bui1突變體植株的節(jié)間發(fā)育,，表現(xiàn)為最上節(jié)間嚴重縮短,，呈彎曲生長。通過與中科院植物所黃善金研究員課題組合作,，他們系統(tǒng)分析了BUI1的生化功能,，證明BUI1參與了微絲骨架裝配的各個過程，并呈現(xiàn)其特有的調(diào)控性能,。該研究通過一系列體內(nèi)染色和體外生化實驗,，證明Class II 成員BUI1是微絲骨架的重要調(diào)控因子，在高等植物微絲骨架裝配和生長發(fā)育中發(fā)揮重要的作用,，該研究同時為水稻株高發(fā)育調(diào)節(jié)提供了一個新的研究方向。
該工作得到了中國科學院知識創(chuàng)新工程,、國家科技部,、國家自然科學基金委等的支持。（生物谷Bioon.com）
生物谷推薦原文出處：
Plant Cell doi:10.1105/tpc.110.081802
BENT UPPERMOST INTERNODE1 Encodes the Class II Formin FH5 Crucial for Actin Organization and Rice Development[W],[OA]
Weibing Yanga,1, Sulin Renb,1, Xiaoming Zhangc,1, Mingjun Gaoa, Shenghai Yec, Yongbin Qic, Yiyan Zhengb, Juan Wangb, Longjun Zenga, Qun Lia, Shanjin Huangb,2 and Zuhua Hea,2,3
The actin cytoskeleton is an important regulator of cell expansion and morphogenesis in plants. However, the molecular mechanisms linking the actin cytoskeleton to these processes remain largely unknown. Here, we report the functional analysis of rice (Oryza sativa) FH5/BENT UPPERMOST INTERNODE1 (BUI1), which encodes a formin-type actin nucleation factor and affects cell expansion and plant morphogenesis in rice. The bui1 mutant displayed pleiotropic phenotypes, including bent uppermost internode, dwarfism, wavy panicle rachis, and enhanced gravitropic response. Cytological observation indicated that the growth defects of bui1 were caused mainly by inhibition of cell expansion. Map-based cloning revealed that BUI1 encodes the class II formin FH5. FH5 contains a phosphatase tensin-like domain at its amino terminus and two highly conserved formin-homology domains, FH1 and FH2. In vitro biochemical analyses indicated that FH5 is capable of nucleating actin assembly from free or profilin-bound monomeric actin. FH5 also interacts with the barbed end of actin filaments and prevents the addition and loss of actin subunits from the same end. Interestingly, the FH2 domain of FH5 could bundle actin filaments directly and stabilize actin filaments in vitro. Consistent with these in vitro biochemical activities of FH5/BUI1, the amount of filamentous actin decreased, and the longitudinal actin cables almost disappeared in bui1 cells. The FH2 or FH1FH2 domains of FH5 could also bind to and bundle microtubules in vitro. Thus, our study identified a rice formin protein that regulates de novo actin nucleation and spatial organization of the actin filaments, which are important for proper cell expansion and rice morphogenesis.
