玉米耐盐碱分子标记克隆及其分子机制的研究

Maize (Zea mays) is one of most important crops for both animal and human. It is moderately sensitive to salt-alkaline stress. Shandong province locates in the central position of corn culture area of China. Yellow River Delta contains more 50 million hectares of land, which are not favorable for crop growth because of the natural characteristics of saline and alkaline soil. Forward and reverse genetic analyses have enabled significant advances in our understanding of the mechanisms mediating plant adaptation to salt stress in model plant system. However, mutation of a single gene rarely produces a significant enhancement in crop salt tolerance. Many genes are important or essential for plant salt tolerance and plants lacking these genes are hypersensitive to salt stress. Overexpression or ectopic expression of these genes only slightly improves crop salt resistance. Plant salt tolerance is a complex trait controlled by quantitative trait loci (QTL). In order to improve maize salt-alkaline tolerance, the determinants of salt-alkaline tolerance have to be identified and their regulatory mechanisms have to be further studied. In this study, we will identify the maize orthologous genes that have been shown to be essential in model plant for salt tolerance, and study their biological function and molecular mechanism, through which we could shorten the period for understanding salt-alkaline-tolerance mechanism in maize and obtaining more molecular markers for maize breeding. We will also perform Quantitative Trait Loci (QTL) and Genome-Wide Association Studies (GWAS) analysis using the high-density mapping populations by crossing salt-resistant (Zheng 58) and salt-sensitive (Chang 72) varieties and more than 700 corn varieties with different degrees of salt resistance for high-throughput phenotyping analysis and sequencing-based cloning, which will enable identification of QTLs and molecular makers that can be used for breeding salt tolerance in maize plants and understanding salt-alkaline-tolerance mechanism in maize.

玉米是我国重要的粮饲两用作物，对盐碱相对敏感。山东省位于中国玉米带的中心位置, 属黄淮海平原夏玉米区, 自然条件非常适合玉米生长。黄河三角洲现有800万亩边际土地多为盐碱地，土壤含盐高、有机质低、营养元素不均衡，不适合农作物生长。研究玉米在该自然条件下特殊的抗性机制及获得重要的耐盐碱分子标记，对提高黄河三角洲乃至全国盐碱地玉米产量均有重要的意义。本申请拟通过生物信息学、分子生物学、和遗传学手段在玉米中筛选模式植物中已知的重要耐盐碱基因的直系同源基因、研究其生物学功能、确定已知耐盐碱机制在玉米中的保守性、缩短在玉米中克隆重要耐盐碱基因和掌握其耐盐碱机制的进程；利用重组自交系和包括山东在内从世界各地收集的玉米自交系进行耐盐碱QTL定位和全基因组关联分析（GWAS），克隆在黄河三角洲盐碱地有重要作用的基因，为创制符合该地区土壤特性的优异玉米新品质，提供耐盐碱基因和分子标记，并揭示其分子调控机制。

玉米是我国重要的粮饲两用作物，对盐碱相对敏感。山东省位于中国玉米带的中心位置，属黄淮海平原夏玉米区，自然条件非常适合玉米生长。黄河三角洲现有800万亩边际土地多为盐碱地，土壤含盐高、有机质低、营养元素不均衡，不适合农作物生长。研究玉米在该自然条件下特殊的抗性机制及获得重要的耐盐碱分子标记，对提高黄河三角洲乃至全国盐碱地玉米产量均有重要的意义。本研究通过生物信息学、分子生物学、和遗传学等手段在玉米中筛选模式植物中已知的重要耐盐碱基因的直系同源基因、研究其生物学功能、确定已知耐盐碱机制在玉米中的保守性、缩短在玉米中克隆重要耐盐碱基因和掌握其耐盐碱机制的进程；利用玉米自交系和重组自交系进行耐盐碱QTL定位和全基因组关联分析，克隆耐盐碱重要基因；为创制符合该地区土壤特性的优异玉米新品质，提供耐盐碱基因和分子标记，并揭示其分子调控机制。通过项目资助，我们克隆了15个与盐碱抗性相关的玉米基因，通过全基因组关联分析和重组自交系耐盐碱分析，初步定位10个QTLs。特别是我们发现重要的耐盐碱机制在玉米中非常保守，我们的研究为把模式植物耐盐机理在作物中的应用提供了理论基础。