OVATE Family Protein 8 Positively Mediates Brassinosteroid Signaling through Interacting with the GSK3-like Kinase in Rice.
OVATE Family Protein 8 Positively Mediates Brassinosteroid Signaling through Interacting with the GSK3-like Kinase in Rice.
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DOI：
10.1371/journal.pgen.1006118
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发表时间：
2016-06
期刊：
影响因子：
4.5
通讯作者：
Li J
中科院分区：
文献类型：
--
作者：
Yang C;Shen W;He Y;Tian Z;Li J
OVATE基因最早在番茄中被鉴定为果实形状的关键调控基因。OVATE家族蛋白（OFPs）是植物特异性转录因子，在拟南芥、番茄和水稻中高度保守。OFPs在植物发育和生长中的作用尚不清楚。甾体类化合物是一类具有多种生物学功能的甾体激素。OsGKS 2通过磷酸化下游组分如OsBZR 1和DLT在BR信号传导中起关键作用。在水稻中，OsOFP 8在BR信号通路中起着积极的作用。BL处理诱导OsOFP 8的表达，并导致OsOFP 8蛋白的积累增加。OsOFP 8基因的功能获得突变体Osofp 8和OsOFP 8过表达株系的叶片联合倾斜度增加，而OsOFP 8 RNAi转基因株系的叶片直立度增加，表明OsOFP 8基因参与了BR反应。进一步的分析表明OsGSK 2与OsOFP 8相互作用并磷酸化OsOFP 8。BRZ处理导致OsOFP 8在胞质中的分布，而比基尼素处理减少了OsOFP 8在胞质中的积累。OsOFP 8被OsGSK 2磷酸化是其核输出所必需的。磷酸化的OsOFP 8穿梭到细胞质中，并被靶向用于蛋白酶体降解。这些结果表明，OsOFP 8是OsGSK 2的底物，OsOFP 8在植物生长发育中的功能至少部分是通过BR信号通路实现的。OVATE家族蛋白（OFPs）是植物特异性转录因子，主要影响果实的形态，但其作用机制尚不清楚。水稻基因组中含有31个OFPs，这些OsOFPs在植物生长发育中的作用尚不清楚。甾体类化合物是一类具有多种生物学功能的甾体激素。在水稻中，OsOFP 8通过与BR信号通路的负调控因子OsGKS 2相互作用，在BR信号通路中发挥正调控作用。我们的研究结果为深入研究OFPs的功能提供了理论依据，也为探索BR信号通路的新组分提供了可能。
OVATE gene was first identified as a key regulator of fruit shape in tomato. OVATE family proteins (OFPs) are characterized as plant-specific transcription factors and conserved in Arabidopsis, tomato, and rice. Roles of OFPs involved in plant development and growth are largely unknown. Brassinosteroids (BRs) are a class of steroid hormones involved in diverse biological functions. OsGKS2 plays a critical role in BR signaling by phosphorylating downstream components such as OsBZR1 and DLT. Here we report in rice that OsOFP8 plays a positive role in BR signaling pathway. BL treatment induced the expression of OsOFP8 and led to enhanced accumulation of OsOFP8 protein. The gain-of-function mutant Osofp8 and OsOFP8 overexpression lines showed enhanced lamina joint inclination, whereas OsOFP8 RNAi transgenic lines showed more upright leaf phenotype, which suggest that OsOFP8 is involved in BR responses. Further analyses indicated that OsGSK2 interacts with and phosphorylates OsOFP8. BRZ treatment resulted in the cytoplasmic distribution of OsOFP8, and bikinin treatment reduced the cytoplasmic accumulation of OsOFP8. Phosphorylation of OsOFP8 by OsGSK2 is needed for its nuclear export. The phospphorylated OsOFP8 shuttles to the cytoplasm and is targeted for proteasomal degradation. These results indicate that OsOFP8 is a substrate of OsGSK2 and the function of OsOFP8 in plant growth and development is at least partly through the BR signaling pathway. OVATE family proteins (OFPs) are characterized as plant-specific transcription factors and mainly function in affecting fruit shape, but the molecular mechanisms by which they function are largely unknown. Rice genome contains 31 OFPs, the roles of these OsOFPs involved in plant development and growth are not understood. Brassinosteroids (BRs) are a class of steroid hormones involved in diverse biological functions. Here we report in rice that OsOFP8 plays a positive role in BR signaling pathway by interacting with OsGKS2, a negative regulator in BR signaling pathway. Our results shed light on studying the functions of OFPs and provide a chance to explore the new components of BR signaling pathway.