AtPGK2介导的叶绿体逆向信号参与拟南芥响应盐胁迫的分子机制

3-磷酸甘油酸激酶（3-PGK）在碳固定、糖酵解和糖异生代谢途径中有重要作用。目前，虽然许多高等植物的PGKs被分离，但是对于其参与植物响应逆境胁迫的机制尚不清楚。本项目前期的研究发现过表达AtPGK2使拟南芥细胞核参与胁迫响应的基因上调表达，转基因植株耐盐性提高；叶绿体功能的缺失导致AtPGK2基因和细胞核胁迫响应基因的表达降低；酵母双杂交试验显示AtPGK2与叶绿体逆向信号的重要组分GUN1互作。进一步研究发现ABI4作为逆向信号途径的组分调控细胞核胁迫响应基因的表达。因此，我们推测AtPGK2可能通过介导叶绿体的逆向信号参与拟南芥响应盐胁迫。本项目在前期研究的基础上，利用生化、分子遗传和分子生物学的方法深入探究AtPGK2介导的叶绿体逆向信号参与拟南芥响应盐胁迫的分子机制。其结果不仅为阐明叶绿体逆向信号在植物响应盐胁迫中的作用提供新的思路，而且为提高作物的耐盐性提供重要的理论依据。

3-Phosphoglycerate kinase (3-PGK) plays a critical role not only in photosynthetic carbon metabolism but also in glycolysis and gluconeogenesis. Although a large number of PGKs have been isolated from a variety of higher plants, their molecular mechanisms involved in plant abiotic stress responses still remain elusive. In the previous studies, we found that over-expression of AtPGK2 conferred salt tolerance in transgenic Arabidopsis plants accompanied by increased expression of stress-responsive nuclear genes. Chloroplast dysfunction causes a significant reduction in the expression levels of AtPGK2 and stress-responsive nuclear genes. GUN1, an important component in chloroplast retrograde signaling, was proved to be a putative AtPGK2-interacting protein by yeast two-hybrid assay. Further studies showed that ABI4 regulates the expression of stress-responsive nuclear genes as a component of the chloroplast retrograde signal pathway. Therefore, we speculated that AtPGK2 is involved in response to salt stress possibly through chloroplast-to-nucleus retrograde signaling in Arabidopsis. Based on these previous experimental data, we will further investigate the molecular mechanisms of AtPGK2-mediated chloroplast retrograde signaling involved in response to salt stress by using biochemical, molecular genetic and molecular biological methods. The results of this study will not only open up new ideas of the research on the roles of chloroplast retrograde signaling involved in plant salt stress responses but also provide the theoretical basis for breeding salt-tolerant crop plants.