一个新的植物向光性遗传调控组分的鉴定

Cell polar behavior depends on fine-tuned cell shape and structure development and genetic regulation components. Plant phototropism is a typical example of polar cell growth. The classical genetics signaling network of blue light mediated phototropism is consisted by blue light receptor PHOTs and its phosphorylation substrates PKSs. However, the genetics members that downstream of PHOTs-PKSs blue light receiving signaling network, thus carrying out phototropism through regulating cell polar elongation remain unknown. Applicant has found that PHOT1 blue light sensor and PKSs interact with FER receptor protein kinase, which working critical in cell growth and environment adaption. Further, FER regulates lateral apoplastic acidification and lateral auxin relocation efflux in lateral illuminated hypocotyl, consequence to faster lateral illuminated cell polar elongation, leading to phototropism. Based on these data, this application will explore: 1. The genetics function of FER in plant phototropism; 2. The genetics and biochemistry mechanisms of FER-PHOTs-PKSs interaction; 3. The cell development mechanism of FER-PHOTs-PKSs regulating plant phototropism. This application will reveal FER as a critical genetics member in PHOTs-PKSs phototropism network, promote the understanding of the crosstalk between plant cell polar behavior and internal/external environment, provide the theoretical basis for agricultural modernization crop genetic improvement.

细胞极性需要诸多遗传因子参与调控，并依赖于精细的细胞形态或结构发育。植物向光性是典型的细胞极性生长，经典的植物蓝光向光性遗传调控网络由蓝光受体PHOTs及其激酶底物PKSs等组成，但植物响应蓝光后调控细胞极性生长发育的遗传网络成员尚不清楚。申请人前期发现PHOT1、PKSs与控制细胞生长和环境适应性的重要受体蛋白激酶FER互作，调节单侧蓝光介导的氢离子和生长素侧向分布，导致背光侧细胞壁酸化、生长素浓度升高，细胞极性生长速度更快，实现向光性。基于此，本项目拟探讨1.FER在向光性中的遗传学作用；2.FER-PHOTs-PKSs互作的遗传和生化机制；3.FER-PHOTs-PKSs调控植物向光过程中细胞发育的机制。本研究发现FER是PHOTs-PKSs向光调控经典途径的重要遗传网络成员，加深了对植物细胞极性运动与内外环境信号交叉会话的机制理解，为农作物遗传改良提供理论基础。

植物向光性弯曲生长受光控的生长素梯度调控。蓝光受体phototropin 1（phot1）感受光的方向，但其如何调控生长素梯度形成尚不清楚。已有研究表明phot1可以调控胞外氢离子，但这一过程与向光性的关系仍不清楚。本研究发现蓝光可以促进phot1与FERONIA（FER）相互作用，并通过磷酸化信号调控向光弯曲生长。fer突变体与phot1/2突变体表现出相似的弱向光表型。FER也可以与phot1下游底物phytochrome kinase substrates（PKSs）相互作用并将其磷酸化。phot1-FER作为胞外酸化和氢离子梯度形成的上游信号通路，是单侧蓝光调控的向光生长所必需的。本研究揭示了FER在phot1介导的植物向光生长中的重要功能。