利用代谢物谱图及全基因组SNP标记挖掘水稻耐盐候选功能基因

Salt stress in one of the major environmental factors limiting rice productivity and it's beneficial to solve the problem of food security by understanding the physiological mechanism and the relative molecular basis for salt tolerance (ST). The hiperosmotic stress is one of the major influences of the salt treatments on plants and many small molecular metabolites participate the osmotic adjustments actively. To date, abundant genetic and gene level researches on ST in rice have been reported, however, the functions of metabolites on ST were ignored greatly. The metabolites are the downstream products of the genes and the "bridges" between genes and phenotypes,meanwhile,they have higher heritability than complex traits. Thus, at present study, the important metabolites related to the ST of rice were analyzed with recombined introgression line (RIL) population derived from the cross between IR29 and Pokkali by metabolic profiling method. The analysis were conducted under both control and salt stress conditions with gas chromatograph-mass spectrometer (GC-MS) technique. The QTL controlling ST metabolites were analyzed with the genome-wide SNP. The candidate genes related to ST metabolites were discovered by combining the information of the important QTLs with bioinformatics.The results presented in this study would improve our understanding on physiological and molecular mechanism of ST in rice and promote the breeding practice.

盐害是限制水稻生产的主要非生物逆境之一，明确耐盐生理代谢及相关分子机制有利于解决粮食安全问题。盐胁迫对植株的主要影响之一是渗透胁迫，已有研究发现有多种小分子物质参与了渗透胁迫反应。目前有大量水稻耐盐遗传学及基因水平的研究报道，但忽视了小分子代谢物在耐盐反应中的作用。代谢物是基因表达的下游产物，是连接基因与表型的"桥梁"，且其遗传力相对较高。针对于此，本项目拟以IR29/Pokkali构建的重组自交系（RIL）群体为研究材料，采用代谢物谱图分析方法，主要利用气质谱联用技术（GC-MS），分析盐处理及对照条件下水稻叶及根部的代谢物特征，高效挖掘耐盐相关代谢物，并结合该群体覆盖全基因组的单核苷酸多态性(SNP)数据，分析相关代谢物的QTL位点及遗传效应；在此基础上，整合生物信息学，挖掘重要代谢物的候选功能基因。研究结果将极大丰富对水稻耐盐代谢机制的理解且有助于推动耐盐育种进程。

盐害是限制水稻生产的主要非生物逆境之一，明确耐盐生理代谢及相关分子机制有利于解决粮食安全问题。盐胁迫对植株的主要影响之一是渗透胁迫，已有研究发现有多种小分子物质参与了渗透胁迫反应。目前有大量水稻耐盐遗传学及基因水平的研究报道，但忽视了小分子代谢物在耐盐反应中的作用。代谢物是基因表达的下游产物，是连接基因与表型的"桥梁"，且其遗传力相对较高。针对于此，本项目以明恢63/02428构建的回交导入系（BC）群体为研究材料，采用代谢物谱图分析方法，主要利用气质谱联用技术，分析盐处理及对照条件下水稻叶及根部的代谢物特征，高效挖掘耐盐相关代谢物，并结合该群体覆盖全基因组的单核苷酸多态性(SNP)数据，分析相关代谢物的QTL位点及遗传效应；研究结果表明，在检测到的136个代谢物中，其中66个代谢物与水稻耐盐表型存在显著相关，并在此基础上检测到17个与水稻耐盐表型或代谢物显著相关的重要位点。在此基础上，整合生物信息学，结合其单倍型及基因表达谱分析结果，挖掘到8个耐盐候选基因，其中三个为已知的耐盐抗逆相关基因。进一步的LOC_Os11g08100和LOC_Os11g08100的单倍型分析发现目标基因不同单倍型对水稻的表型及代谢物均有显著影响。另外，研究发现来自02428的等位基因多对表型性状有降低作用，而对重要代谢物含量有增加效应，表明代谢物含量增加是植物遭遇逆境的一种适应性反应。研究结果将有助于推动耐盐育种进程。