棉花液泡膜质子转运焦磷酸酶基因（GhVP1）抗逆功能及其分子机制研究

The ankyrin-repeat containing protein 2A (AKR2A) functions as a highly efficient molecular chaperone in Arabidopsis. Overexpressing of AKR2A confers increased stress tolerance.However,they were found to be decreased significantly in the akr2a mutant plants when compared the wild-type plants.Our preliminary data indicate that GhAKR2A interacts with a group of membrane-binding proteins related to plant stress response including the H+-PPase (Ⅰ),GhAVP1. The ability of drought and salt tolerance was increased in either the overexpresion of AKR2A or AVP1 transgenic cotton, and co-overexpression of AKR2A and AVP1 in cotton further improved drought and salt tolerance in transgenic cotton plants. Therefore, AKR2A should play important roles in protein biogenesis of some membrane-binding stress response related proteins, and the subsequent stress tolerance at the upstream regulatory networks in cotton.. The objectives of our research project are ①.identification of GhAKR2A’s interacting proteins involved in stress responses in cotton by using a large scale yeast two-hybrid screens and protein ，study of the interacting mechanism between AKR2A and its interacting proteins. Study of the way and the mechnism of GhAKR2A’s “chaperone”. ②.Study the stress response mechanism and regulatory mechanism mediated by the vacuolar membrane protein biogenesis of the H+-pyrophosphatase gene AVP1 in cotton. Cloning and identifying new functional genes. ③Making a technical assessment that co-overexpression of AKR2A and AVP1 in cotton could further improve drought and salt tolerance in transgenic cotton. . This study is expected to enrich the achievement of molecular chaperone as a regulatory element of the biogenesis of membrane-binding proteins, and to membrance protein biogenesis-mediated stress response at upstream regulatory networks. It may also construct a genetic engineering system to create a stress tolerant new cotton variety (germplasm) intentionally.

申请人发现AKR2A是拟南芥中的一个高效分子伴侣。AKR2A突变体对逆境特别敏感，但过量表达提高了植株的抗逆能力。新近的研究又发现棉花GhAKR2A与一组逆境应答相关的膜蛋白相互作用，包括液泡膜GhAVP1。过表达AKR2A和AVP1均能提高棉花的抗旱抗盐能力，而双基因过表达能进一步提高植株的抗逆能力。我们推断，AKR2A处在VP1的上游调控棉花的抗逆能力。为此：①通量筛选受GhAKR2A调控、参与棉花逆境应答的基因（组）。明确GhAKR2A对GhVP1的“伴侣”方式和机制。②探明GhAKR2A介导GhVP1生物生成提高棉花抗逆能力的生理和分子机制，鉴定新的基因。③AKR2A和VP1协同作用进一步提高棉花抗逆能力和棉花产质、量的技术评估。本研究学术上可丰富棉花伴侣蛋白在膜蛋白生物生成中的学术成果，从功能基因上游阐明液泡膜蛋白生物生成介导的逆境应答机制；技术上有望创建抗逆棉花新种质。

拟南芥液泡膜质子转运焦磷酸酶H+-PPase（VP1）在干旱和盐胁迫响应中起重要作用。过表达AKR2A和AVP1均能提高棉花的抗旱抗盐能力，而双基因过表达能进一步提高植株的抗逆能力。为探究AKR2A和AVP1共同调节植株抗逆性的机制，本项目通过通量筛选受GhAKR2A调控、参与棉花逆境应答的基因（组），阐述GhAKR2A对GhVP1的“伴侣”方式和机制。本项目在棉花中共过表达AVP1和AKR2A，阐明了AKR2A和AVP1如何调控植物生长素的生物合成和转运，以及它们在转基因棉花调节Na+通量的相互作用机制。这些结果阐述了GhAKR2A介导GhVP1生物生成提高棉花抗逆能力的生理和分子机制，明确了AKR2A和VP1协同作用进一步提高棉花抗逆能力和棉花的产量和质量。