光形态建成核心因子HY5及其候选靶基因TINY互作调控根系构型的机制研究

根系构型影响产量和株型等性状，对农作物生产至关重要，是植物发育的主要研究对象之一。侧根是根系构型的重要组成部分，然而我们对环境因子尤其是光调控侧根伸长的机制知之甚少。HY5是光和生长素信号交互调控侧根伸长的主要整合因子。前期结果表明光通过HY5抑制侧根伸长和根系扩张。我们建立了一个根避光培养体系来研究HY5调控根系构型的机制，并通过RNA-Seq数据分析、qRT-PCR和表型鉴定等一系列预实验鉴定了1个候选的HY5下游因子，即TINY (AT5G25810)。本项目拟通过遗传学、细胞生物学和生化等手段，从表型、表达及功能等方面研究TINY参与根的光应答反应的作用，并揭示HY5与TINY互作来调控根光形态建成的作用机制。期望通过本研究为揭示根光形态建成的分子网络提供新的线索，为通过基因工程改良根系构型以提高作物环境适应性和改良作物性状提供理论依据和可行性基础。

Root system architecture (RSA) is one of the most important research subjects in plant development and plays a major role in plant fitness, crop performance, and grain yield. Lateral root (LR) contributes essentially to RSA, however, how environment factors, especially light, regulate LR elongation is largely unknown. Previous study indicated that HY5 is the core integrator of light and auxin crosstalk in controlling LR elongation, while light inhibits LR elongation and therefore decreases root system architecture. By applying a series of pilot experiments such as RNA-Seq, qRT-PCR and phenotype survey with assistance of a new established root-solitary shaded culture system (Root Shaded System, RSS)，we identified a novel HY5 putative downstream factor, TINY (AT5G25810). Here, we will investigate the novel function of TINY in light response in Arabidopsis root, and uncover the underlying mechanism of HY5 and TINY interaction and their roles in root photomorphogenesis by using combined approaches of genetic, cell biological and biochemistry in this study. Overall, we expect to present new clues to fill up molecular network in regulating root photomorphogenesis, and therefore providing new strategy to help crop plants fit themselves to environment and improve agronomic traits.