The plant Journal：中科院微生物所发现植物抗病反应与种子萌发的

中科院微生物所发现植物抗病反应与种子萌发的共同调控蛋白

种子萌发是高等植物生命周期的又一个开始，其受到多种环境因子和植物激素的影响。其中最重要因素是赤霉素(Gibberellins，GAs)。当植物种子吸水后，胚开始合成GAs并释放到糊粉层细胞。糊粉层细胞接受到GAs信号后开始合成水解酶(如α-淀粉酶)并分泌到胚乳中水解淀粉为小分子糖，为种子萌发与幼苗生长提供能量。

水稻抗病调控蛋白OsLOL1在水稻抗病中起到重要作用，但中国科学院微生物研究所植物基因组学国家重点实验室吴家和博士研究发现，OsLOL1同时也能够调控GAs生物合成继而影响水稻种子萌发。当水稻中OsLOL1基因被反义抑制后，GAs合成基因OsKO2表达下降造成其中间产物ent-kaurene大量积累。酵母双杂交和荧光互补实验结果显示，OsLOL1能与碱性亮氨酸拉链蛋白OsbZIP58互作。电泳迁移率与双荧光报告分析显示，OsbZIP58能结合OSKO2基因启动子中G-box顺式元件并启动Luc报告基因表达。此外，OsLOL1能下调SOD1基因表达并加速水稻糊粉层细胞凋亡。研究结果证明，OsLOL1与OsbZIP58互作促进OsKO2基因表达来调控GAs的生物合成，从而影响糊粉层细胞的凋亡和种子萌发。

该项研究成果已经发表于植物科学领域权威期刊The plant Journal。吴家和为第一作者。此项研究得到国家自然科学基金(no. 30571055)和国家科技部的资助(no. 2012CB722206)。

图示：OsLOL1调控水稻种子萌发的分子机制(图片来自吴家和博士) (微生物所供稿)

原文链接：

OsLOL1, a C2C2-type zinc finger protein, interacts with OsbZIP58 to promote seed germination through the modulation of gibberellin biosynthesis in Oryza sativa

原文摘要：

Seed germination is a key developmental process in the plant life cycle that is influenced by various environmental cues and phytohormones through gene expression and a series of metabolism pathways. In the present study, we investigated a C2C2-type finger protein, OsLOL1, which promotes gibberellin (GA) biosynthesis and affects seed germination in Oryza sativa (rice). We used OsLOL1 antisense and sense transgenic lines to explore OsLOL1 functions. Seed germination timing in antisense plants was restored to wild type when exogenous GA3 was applied. The reduced expression of the GA biosynthesis gene OsKO2and the accumulation of ent-kaurene were observed during germination in antisense plants. Based on yeast two-hybrid and firefly luciferase complementation analyses, OsLOL1 interacted with the basic leucine zipper protein OsbZIP58. The results from electrophoretic mobility shift and dual-luciferase reporter assays showed that OsbZIP58 binds the G-box cis-element of the OsKO2 promoter and activates LUC reporter gene expression, and that interaction between OsLOL1 and OsbZIP58 activates OsKO2 gene expression. In addition, OsLOL1 decreased SOD1 gene expression and accelerated programmed cell death (PCD) in the aleurone layer of rice grains. These findings demonstrate that the interaction between OsLOL1 and OsbZIP58 influences GA biosynthesis through the activation of OsKO2 via OsbZIP58, thereby stimulating aleurone PCD and seed germination.

作者：生物帮