水稻基因REL1在叶形态调控中的生物学功能分析

Leaf morphology is one of the most important agronomic traits for rice breeding. Moderate leaf rolling and bending benefit the higher efficiency of photosynthesis and reducing the transpiration, which leads to increase the biomass and tolerance to drought, eventually resulting in increasing the rice yields. In our previous study, we isolated and characterized a leaf morphology related mutant, rolled and erect leaf 1 (rel1). Molecular cloning revealed that rel1 is controlled by the dominant REL1 gene, which encodes an unknown protein despite that REL1 protein is highly conserved among monocot plants. We also found that REL1 apparently coordinates the BR pathway to regulate leaf rolling and bending. However, the biological function of REL1 is still not clear, and the interplay between REL1 and BR remains elusive. In the present project, we attempt to elucidate the regulatory mechanism underlying how REL1 regulates leaf morphology through the employment of various approaches. Furthermore, we also attempted to confirm and elucidate the function of REL1-correlated genes and REL1-interacting proteins, which eventually assists us to construct the regulatory network of REL1-mediated leaf morphology. We wish that our findings would benefit the genetic improvement of rice breeding through the molecular manipulation of leaf rolling and bending in the future.

水稻基因REL1被克隆并被证实能协同激素BR相关基因参与叶形态的调控，它控制叶片的卷曲、并通过增强OsBZR1的表达来增大叶角度。利用酵母双杂交，已筛选和鉴定出了7个与REL1互作的蛋白；利用酵母单杂交，已筛选和鉴定出了8个可能参与抑制REL1表达的候选蛋白，其中SRE1基因编码一个转录因子，最可能是REL1的抑制因子。本项目就是在此基础上利用BiFC和co-IP等技术，确认7个RIPs 和REL1之间的互作；通过基因过表达和敲除技术研究7个RIPs和SRE1的功能；利用Luciferase Assay和CHIP技术确认SRE1和REL1的启动子特殊区域的结合；通过基因过表达和敲除技术研究OsBZR1和REL1的关系，并用BiFC和co-IP技术求证二者是否存在蛋白间的结合。总之，本项目将揭示和解析水稻基因REL1在叶形态调控中的生物学功能，为培育出高产、适应性强的水稻新品种提供理论依据。

水稻基因REL1被克隆并被证实能协同激素BR相关基因参与叶形态的调控，它控制叶片的卷曲、并通过增强OsBZR1的表达来增大叶角度。本项目在此基础上利用BiFC或Y2H等技术，确认REL1分别与RIP2和RIP5在水稻质体中互作，而与RIP3和RIP4则在细胞核中互作；抗旱与组学实验结果证明REL1通过激素ABA途径提高水稻的耐旱性；解析RIP2与REL1通过激素BR调控水稻叶夹角的分子机制；初步揭示REL1协同RIP4、RIP5和RIP6调控水稻叶极性的分子机制，等等。总之，本项目进一步解析了水稻基因REL1在叶形态和耐旱调控中的生物学功能，为培育出高产、适应性强的水稻新品种提供理论依据。