Liu Fei, Zhang Lan, Luo Yanzhong, Xu Miaoyun, Fan Yunliu, Wang Lei
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Haidian District, Beijing, China.
New Phytol. 2016 Oct;212(1):96-107. doi: 10.1111/nph.14021. Epub 2016 Jun 6.
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, (3) H-indole-3-acetic acid ((3) H-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.
关于细胞内生长素的转运机制，人们了解甚少。在此，我们报道了两种定位于液泡的蛋白质，即水稻的水稻连续维管束环样蛋白1（OsCOLE1）和OsCOLE1相互作用蛋白（OsCLIP），它们调节细胞内生长素的转运和稳态。OsCOLE1的过表达显著增加了茎基部的节间长度和生长素含量，而在RNA干扰（RNAi）植株中这些参数则降低。OsCOLE1定位于液泡膜，且在成熟组织中优先表达。我们进一步鉴定了其相互作用蛋白OsCLIP，它与OsCOLE1共定位于液泡膜。蛋白质-蛋白质结合试验表明，OsCOLE1的N端在酵母细胞和水稻原生质体中直接与OsCLIP相互作用。此外，（3）H-吲哚-3-乙酸（（3）H-IAA）转运试验表明，OsCLIP将IAA转运到酵母细胞中，这一过程受到OsCOLE1的促进。结果表明，OsCOLE1通过与OsCLIP相互作用调节细胞内生长素转运，从而影响水稻发育，这为生长素细胞内转运的调控机制以及液泡在植物发育中的作用提供了新的见解。
