玉米LRR3基因调控根系发育及抗倒伏的分子机制研究

玉米是我国重要的农作物，但其生产一直受倒伏问题制约。已知玉米根系与其抗倒伏能力密切相关，且节根和支持根起主要作用。但目前只有少数调控玉米根系发育的基因被鉴定出来，且分子机制也不清楚。项目组前期发现了一个新基因，并命名为LRR3。初步结果表明LRR3的功能缺失会促进节根和支持根的发育，增强玉米的抗倒伏能力。前期研究还发现LRR3定位于细胞核上，且与调控节根和支持根发育的关键蛋白ZmRDP1可能相互作用。为深入研究LRR3的功能，本项目拟通过细胞生物学技术分析LRR3基因的表达模式；通过鉴定LRR3的互作蛋白，分析LRR3可能的生化机制；通过鉴定LRR3启动子结合蛋白，找到LRR3上游的调控因子；通过RNA-Seq和ChIP-Seq，明确LRR3调控的下游基因，最终阐明LRR3基因调控根系发育和抗倒伏的分子机制。本项目的研究结果将为改良玉米根系构型和提高抗倒伏能力的种质创新提供新的基因资源。

Maize is one of the main food crops in China, but its production has been restricted by the lodging problem. The root configuration of maize is closely related to its lodging resistance, and its crown roots and brace roots play an important role in preventing lodging. But now only a few maize genes involved in regulating the root development have been identified, and the molecular mechanism of these genes are still not clear. Based on our previous study, a new gene (named LRR3) that significantly affected maize root development was found. LRR3 gene encodes a protein that is located in the nucleus, and the function of LRR3 has heretofore not been studied. Preliminary results showed that the loss-of-function mutation of LRR3 promotes the development of crown roots and brace roots, and increases the lodging resistance of maize. While gain-of-function mutation of LRR3 inhibits the development of crown roots and brace roots, and decreases the lodging resistance of maize. The expression level of LRR3 gene is significantly decreased with the increase of auxin treatment time. In addition, the expression levels of auxin signaling and cell division related genes are also obviously regulated in LRR3-related mutants. LRR3 possibly interacts with ZmRDP1, which is a key protein in regulator of the development of crown roots and brace roots. In this project, we aim to identify the expression pattern of LRR3 gene by cell biology observation and in situ hybridization technology. We aim to understand the genetic network of LRR3 by identifying LRR3 interacting proteins and studying their genetic relationship. We aim to study the regulatory factors acting on the upstream of LRR3 gene by identifying LRR3 cis-element binding protein. We aim to identify the downstream target genes of LRR3 by RNA-Seq and CHIP-Seq analyzes. Finally, the molecular mechanism of LRR3 gene regulating root architecture could be elucidated. .The results of this project will provide new genetic resources for germplasm innovation research and improve maize root configuration to increase maize lodging resistance.