桃果实中两个类胡萝卜素合成关键酶PSY和GGPS相互作用的分子调控机制

类胡萝卜素合成可以影响桃果实的营养价值、着色和风味。八氢番茄红素合成酶PSY是催化形成第一个类胡萝卜素分子的关键限速酶；PSY为了竞争底物GGPP，必需同GGPP合成酶GGPS建立蛋白互作。然而，PSY-GGPS互作形成的分子机制不明。项目前期，申请人基于桃果实特异性PSY和GGPS基因筛选、蛋白互作docking、酵母双杂和基因功能分析，发现桃果实PSY蛋白中一个氨基酸残基可以影响PSY-GGPS的蛋白互作强度和功能。此外，据报道，招募蛋白可以辅助GGPS参与蛋白互作和蛋白复合体形成。基于以上研究，该项目拟利用工程菌系统、蛋白互作、有色体分离及PSY-GGPS相关蛋白复合体鉴定，以及转基因功能验证等手段，挖掘桃果实中参与PSY-GGPS互作的关键氨基酸残基以及辅助性蛋白，以期揭示PSY-GGPS互作形成的分子调控机制及其对桃果实类胡萝卜素合成的影响，为桃果实品质提升技术研发提供理论依据。

Carotenoid biosynthesis can provide nutritional value, color, and flavor for peach fruits. Phytoene synthase (PSY) is a rate-limiting enzyme for producing the first carotenoid molecule. PSY needs to achieve the interaction with GGPP synthase (GGPS) for capturing substrate GGPP. However, the molecular regulation of PSY-GGPS interaction is still unclear. In our previous study, through searching fruit-specific PSY and GGPS genes, protein-protein docking, yeast two hybrid, and gene function analysis, one amino acid residue in the fruit-specific PSY was found to be crucial for both PSY-GGPS interaction and its function. In addition, it is reported that the recruiting protein can assist GGPS to form both protein interaction and protein complex. In the present proposal, through various research techniques including the engineered bacterial system, protein interaction, chromoplast purification and protein complex analysis, functional identification of transgenes and so on, we intend to search the crucial amino acid residues and accessory proteins, both of which construct the PSY-GGPS interaction. Implementation of the present proposal is expected to reveal the molecular regulation of PSY-GGPS interaction and its function in regulating carotenoid biosynthesis in peach fruits, which can provide theoretical basis for quality improvement of peach fruits.