拟南芥AtRAM1/SHR调控盐胁迫下根生长发育的分子机制

Salt stress seriously affects plant growth and development, which is the biggest obstacle to agricultural production. The root system is in direct contact with and regulated by salt environment, however, the molecular mechanism of plant root system in response to salt stress is still unclear. In the previous studies, we identified an Arabidopsis root growth salt-sensitive mutant, named rsm1 (root growth sensitive to salt mutant 1, RSM1), in the forward genetic screen. By map-based cloning, we found AtRSM1 encodes a GRAS family transcription factor, SHR (SHORT-ROOT). The gene expression of RAM1/SHR was inhibited by NaCl, and RAM1/SHR gene could rescue the phenotype of rsm1 primary root growth inhibited by NaCl. This project intends to further analyze the effect of RSM1 on root growth and development under salt stress. RNA-sequencing is used to analyze the difference genes expression between rsm1 and wild-type under salt stress, to elucidate the signal pathway and molecular mechanism of RSM1/SHR in response to salt stress, which would enrich our understanding of theoretical basis and provide candidate genes for the improvement of salt-resistant traits in crops.

盐胁迫严重影响植物生长发育，是制约作物产量的重要因素。根系与盐环境直接接触，并受其调控，但植物根系响应盐胁迫的分子机制仍缺乏足够了解。本研究前期通过正向遗传学的方法，筛选获得拟南芥根生长对盐敏感突变体rsm1 (root growth sensitive to salt mutant 1, RSM1)。图位克隆确定RSM1基因编码一个GRAS家族转录因子SHR (SHORT-ROOT)，NaCl抑制该基因的表达，RAM1/SHR基因能够回补rsm1主根生长受NaCl抑制的表型。本项目拟进一步分析拟南芥RSM1对盐胁迫下根生长发育的影响，利用RNA-seq技术分析盐胁迫下rsm1与野生型基因表达的差异，揭示RSM1/SHR响应盐胁迫的信号通路及分子机制，为农作物抗盐性状的改良提供理论依据和候选基因。

盐胁迫严重影响植物生长发育，是制约作物产量的重要因素。根系与盐环境直接接触，并受其调控，但植物根系响应盐胁迫的分子机制仍缺乏足够了解。本研究前期通过正向遗传学的方法，筛选获得拟南芥根生长对盐敏感突变体ram1 (root architecture mutant 1, RAM1)。图位克隆确定RAM1基因编码一个GRAS家族转录因子SHR (SHORT-ROOT)，RAM1/SHR基因能够回补ram1主根生长受NaCl抑制的表型。系统进化分析发现RAM1/SHR基因在植物中具有保守性。进一步分析发现盐胁迫下ram1根细胞大小和形态发生改变，盐胁迫抑制了RAM1/SHR和根特异细胞标记SCR和J0121的蛋白表达，使突变体ram1根中的ROS水平显著升高，Na+离子外排能力降低。利用RNA-seq技术分析了盐胁迫下ram1与野生型差异表达基因，对参与RSM1/SHR响应盐胁迫的信号通路基因进行了分析。总之，本项目明确了RAM1/SHR在植物抗盐中的作用，为改良作物抗盐性状和培育抗盐农作物提供理论依据和候选基因。