DHF-CBS调节多倍体水稻开花期抗旱的功能及机制研究

开花期干旱是导致水稻减产的关键因素，前期研究表明四倍体水稻开花期抗旱性比二倍体显著提高。花药基因组和蛋白质组关联分析表明，DHF-CBS (Drought-High-Fertility-CBS)的表达受基因剂量和干旱胁迫的双重正调控。dhf-cbs开花期抗旱性显著下降，花粉发育异常，结实率降低，基因功能补偿后恢复正常。DHF-CBS编码的胱硫醚β-合成酶参与的同型半胱氨酸代谢，是合成抗氧化物质谷胱甘肽的关键环节。推测DHF-CBS突变导致同型半胱氨酸代谢受阻，谷胱甘肽合成下降，抗氧化能力降低，DNA损伤加重，最终影响水稻开花期抗旱性。本申请拟详细研究多倍化对水稻开花期抗旱性的影响；进一步分析多倍化对DHF-CBS结构和甲基化的差别调节；重点探究多倍化对DHF-CBS的时空表达模式及其功能的调控；深入剖析其调控抗旱性的代谢通路并寻找其互作因子。以期全面解析多倍体水稻开花期抗旱性的调控机制。

Drought stress at flowering stage is the key factor of rice yield reduction. Polyploid rice has potential drought resistance advantages, comparative proteomic and genomic of anther were compared, DHF-CBS (Drought-High-Fertility-CBS) was screened in the HN2026-4x which was significantly high expressed confirmed by real time RT-PCR. The expression of DHF-CBS in rice was remarkably increased after drought stress. The drought resistance and antioxidant capacity of polyploid rice were significantly dropped after loss the function of DHF-CBS, drought resistance became normal after DHF-CBS function compensated in rice. DHF-CBS encodes a cysteine beta synthase, which mediates the conversion of homocysteine to cysteine, thereby affecting glutathione synthesis. It was speculated that the mutation of DHF-CBS leads to the pathway of synthesis of glutathione, and the antioxidant ability of ascorbate glutathione cycle is blocked, which ultimately affects the drought resistance of polyploid rice during flowering stage. According to the former results, we will study genome duplication in rice affect drought resistance at flowering stage; screen changes in promoter, regulatory elements and methylation of DHF-CBS; resolve the essential function of DHF-CBS and the molecular mechanism of DHF-CBS regulating drought resistance. In-depth analyze its metabolic pathways regulating drought resistance and finding its interaction factors. All these will contribute to explaining the cytological and molecular mechanism about the drought resistance of polyploidy rice comprehensively that will supply the theory guidance for selection the key germ plasm of polyplod rice breeding.