青藏高原大麦种子耐盐萌发有利基因发掘

Soil salinization is one of the main factors that restrict agricultural production. In this study, many barley germplasm materials from different areas will be introduced and a natural population will be constituted according to their origin, kinships and germination index. Then 6-10 salt resistant materials and 6-10 sensitive materials will be selected, and with them, physiological indexes will be measured in a detailed salt stress germination experiment. After the correlation analysis between physiological indexes and germination index and principal component analysis, the main physiological indexes that can increase salt tolerance will be determined, and then these physiological indexes of all materials will be detected. A comprehensive evaluation of salt resistance of various materials is to be performed and the most salt-tolerant one is to be determined. The genotypes of all materials will be determined after polymorphism screening using molecular markers, for the analysis of population genetic structure and genetic diversity. With the tolerance evaluation results, association analysis between markers and salt tolerant traits will be performed to exploit 2-4 favourable alleles of salt tolerance. The germs in germination test under salt stress and no stress at different time intervals is to be taken for the extraction of total RNA and protein for the transcriptome sequencing iTRAQ-based proteomics. After ioinformatics analysis, the molecular mechanisms of the germination of barley seeds under salt stress will be illuminated and 4-6 salt-tolerant candidate genes will be selected.

土壤盐渍化是制约农业生产的主要因素之一。本研究拟引进来源广泛的大麦种质材料，做初步盐胁迫萌发试验，根据来源和亲缘关系选择材料和萌发指标，构成自然群体，确定6-10份耐盐和6-10份敏感型材料，并对其进行详细的盐胁迫萌发试验，测定各项生理指标，经相关性分析和主成分分析确定影响耐盐性的主要生理指标。对各材料的主要生理指标进行测定，结合萌发指标综合评价其耐盐性，筛选出最耐盐材料。结合分子标记检结果，进行标记与性状的关联分析，发掘出耐盐有利等位变异2-4个。对最耐盐材料分不同时间梯度进行盐胁迫萌发试验，取不同时间点的胚芽提取总RNA和蛋白，进行转录组测序和iTRAQ蛋白组学分析，结合生物信息学分析，阐明大麦种子萌发初期耐盐分子机制，筛选耐盐候选基因4-6个。

盐胁迫严重影响植物正常生长发育。土壤盐渍化已成为制约农业生产的主要因素之一。发掘耐盐有利基因是进行盐胁迫响应分子机制研究进而培育耐盐新品种的基础。如何高效地综合评价不同种质的耐盐性是发掘耐盐基因的前提。本研究基于来源广泛的大麦种质资源，通过耐盐性鉴定，结合遗传多样性分析，构建了包含187份不同大麦种质的关联分析自然群体；对10份耐盐材料、10份敏感型进行萌发指标、各项生理指标测定，确定了种子萌发过程中的发芽率、根长、芽长、鲜重等主要盐胁迫响应指标，综合评价了自然群体材料的耐盐性，筛选出5份耐盐材料和5份敏感型材料。选取大量分子标记对自然群体进行遗传分析，以一般线性模型和混合线性模型进行标记与性状的关联分析，发掘出7个有利等位变异；构建了以5份耐盐型和5份敏感型材料为亲本的分离群体。通过转录组、蛋白质组学分析，发现大麦种子萌发过程中对盐胁迫响应的分子机制十分复杂，涉及物质、能量的合成代谢、信号转导、物质转运、激素调节等生物学过程。筛选出耐盐有利候选基因27个，利用qRT-PCR技术验证了部分选基因的表达量。采用RACE技术克隆了候选基因HvMBF1c的CDS全长序列。研究结果为后期开展种子萌发期耐盐萌发分子机制研究及耐盐新品种培育提供了有利候选基因。