New Phytol:农科院生物所王磊研究组发表植物细胞内生长素运输调
2016年6月6日，国际著名植物学期刊《New Phytologist》在线发表了中国农业科学院生物技术研究所作物基因组及遗传改良研究室关于植物细胞内生长素运输调控机制的研究进展。生物所2012级博士生刘飞为文章第一作者，王磊研究员为通讯作者。
生长素是植物体内一类重要的激素，在植物生长发育过程的多个方面均发挥着极其重要的作用。生长素的运输调控过程对维持植物的正常生长发育具有重要影响。近年来，在植物细胞与细胞之间的生长素运输调控机制研究上取得了较大进展，但对于生长素在植物细胞内的运输过程及调控机制仍知之甚少。
通过对构建的水稻RNAi突变体库的筛选，研究人员分离得到了一个影响水稻灌浆期茎秆长度的突变体。对突变体的进一步研究发现，突变体内发生表达下调的为一个未知功能的新基因OsCOLE1(OsCOV-LIKE 1)，可影响水稻基部节间生长素的含量。该基因的同源基因在多种类型植物中均高度保守。亚细胞定位与组织表达水平分析结果表明，OsCOLE1定位于细胞液泡膜上，在水稻生长发育的各个阶段均有表达。通过结合酵母双杂交文库筛选，分裂泛素酵母双杂交实验及荧光双分子互补实验，发现了OsCOLE1在细胞内的互作蛋白质OsCLIP (OsCOLE1-INTERACTING PROTEIN)。通过对OsCLIP的蛋白质结构、亚细胞定位及生长素运输能力的分析，确定OsCLIP为水稻中一个全新的定位于液泡膜的生长素转运体。OsCOLE1通过与OsCLIP相互作用，直接调控OsCLIP对生长素的运输能力。本研究发现了一个新的液泡膜生长素转运体及其调控蛋白，首次在分子水平上揭示了存在于植物细胞液泡上的一种全新的生长素运输调控模式，进一步拓展了人们对于生长素运输过程的已有认知。
植物细胞内生长素运输调控机制
原文链接：
Interactions of Oryza sativa OsCONTINUOUS VASCULAR RING-LIKE 1 (OsCOLE1) and OsCOLE1-INTERACTING PROTEIN reveal a novel intraCellular auxin transport mechanism
原文摘要：
Little is known about the transport mechanism of intracellular auxin. Here, we report two vacuole-localized proteins, Oryza sativa OsCONTINUOUS VASCULAR RING-LIKE 1 (OsCOLE1) and OsCOLE1-INTERACTING PROTEIN (OsCLIP), that regulate intracellular auxin transport and homoeostasis.
Overexpression of OsCOLE1 markedly increased the internode length and auxin content of the stem base, whereas these parameters were decreased in RNA interference (RNAi) plants. OsCOLE1 was localized on the tonoplast and preferentially expressed in mature tissues. We further identified its interacting protein OsCLIP, which was co-localized on the tonoplast.
Protein−protein binding assays demonstrated that the N-terminus of OsCOLE1 directly interacted with OsCLIP in yeast cells and the rice protoplast. Furthermore, 3H-indole-3-acetic acid (3H-IAA) transport assays revealed that OsCLIP transported IAA into yeast cells, which was promoted by OsCOLE1.
The results indicate that OsCOLE1 affects rice development by regulating intracellular auxin transport through interaction with OsCLIP, which provides a new insight into the regulatory mechanism of intracellular transport of auxin and the roles of vacuoles in plant development.
作者：王磊
