GmSTOP1-3控制大豆根系响应低磷胁迫的分子调控机制

Phosphorus (P) deficiency and low pH are major limiting factors for crop production on acid soils. Our previous results showed that the expression of GmALMT1 was regulated by both of P deficiency and low pH, indicating that a common signaling pathway might present in plant response to both stresses. Furthermore, we found that a transcriptional factor, GmSTOP1-3, was involved in the regulation of GmALMT1 expression. Overexpressing GmSTOP1-3 could restore the acid tolerance of stop1 mutant, indicating the functions of GmSTOP1-3 in soybean low pH tolerance. Moreover, the expression of GmSTOP1-3 was enhanced by P deficiency. Overexpressing GmSTOP1-3 led to enhanced plants root growth under low P condition. The results indicated that GmSTOP1-3 might be a novel regulator in the P signaling network. In this project, we will further study root growth and P content of the transgenic soybean plants or hairy roots with overexpressing or suppressing GmSTOP1-3. Subsequently, the RNA-seq will be conducted to examine the global gene expression regulated by GmSTOP1-3. In addition, the proteins interacted with GmSTOP1-3 will be isolated by Co-IP and characterized. The results of this project will build a new P signaling pathway including GmSTOP1-3 as the main regulator, and thus provide useful theoretical foundation for developing soybean varieties, which coordinately and well adapt to both P deficiency and low pH on acid soils.

低磷和低pH是酸性土壤限制作物生长的重要原因。我们前期发现低磷和低pH调控了大豆GmALMT1的表达，暗示大豆根系对低磷和低pH的响应存在共同调控途径。我们克隆了参与调控GmALMT1表达的GmSTOP1-3基因。该基因的超量表达能够恢复拟南芥stop1突变体对低pH的耐性，说明GmSTOP1-3调控了大豆对低pH胁迫的适应性。另外，GmSTOP1-3的表达受低磷上调，且其超量表达促进了低磷条件下转基因株系根系的生长。这些结果表明，GmSTOP1-3可能是大豆根系磷信号网络中一个新的调控因子。本项目拟通过对GmSTOP1-3超量或抑制表达转基因大豆材料根系生长和磷吸收的分析，结合分析其下游基因的表达模式以及互作蛋白的鉴定等，阐明GmSTOP1-3控制大豆根系生长的功能，建立以GmSTOP1-3为核心的大豆根系响应低磷胁迫的调控途径，为培育协同适应低磷和低pH胁迫的大豆品种奠定理论基础。

本项目结合分子生物学，蛋白质组学和转录组学等多种工具和技术，对以GmSTOP1为核心的大豆适应酸性土壤中低磷和酸胁迫的调控网络进行了研究。主要获得了以下的结果：.1）.系统地比较分析了大豆基因组中3个GmSTOP1基因家族成员的表达模式，亚细胞定位和转录激活活性等。进一步对回补表达这些基因的拟南芥突变体atstop1适应酸铝胁迫的表型进行了分析，明确了这些同源基因在植物适应酸铝胁迫中的功能的异同；为进一步解析GmSTOP1在大豆根系适应低磷胁迫的功能奠定了基础。.2）.通过大豆整株转化体系，获得了超量表达GmSTOP1-3的转基因大豆植株。对转基因大豆根系适应低磷胁迫的表型进行了系统的分析，同时通过RNA-SEQ转录组测序的途径，明确了GmSTOP1-3在大豆根系适应低磷胁迫中的调控功能，解析了GmSTOP1-3对下游基因表达的调控网络。选取GmSTOP1-3调控的下游苹果酸转运子基因，对该基因家族成员响应低磷胁迫的表达模式进行了系统分析，也进一步选取其中一个苹果酸转运子基因GmALMT5进行了功能分析，明确了该基因在根系适应低磷胁迫中的功能。.3）.构建了酵母双杂文库。利用该文库鉴定了GmSTOP1-3的互作蛋白。并对其相互作用进行了酵母双杂和BiFC的验证。该互作蛋白功能的分析正在稳步进行。.4）.通过转录组测序和蛋白组测序，分别明确了酸胁迫和低磷胁迫对大豆根系差异表达基因和差异表达蛋白；这些结果解析了酸性土壤中的酸胁迫和低磷胁迫对大豆养分吸收的分子调控机制，阐明了大豆细胞壁蛋白的调控在大豆活化和利用难溶磷中的重要作用。.研究结果初步解析了以STOP1为核心的大豆根系适应低磷和酸胁迫的分子机制，为培育适应酸性土壤的大豆品种提供理论依据和重要基因资源。.