异源四倍体棉花耐盐性状的遗传解析

Cotton is the important fiber and oil crop in China. But the cotton plantation areas have been reduced seriously, accounting for more and more arable land is used for food production. And thus one of the important strategies for the cotton production safety is cultivating saline lands. Upland cotton (Gossypium hirsutum) is the main cultivated cotton variety which is lack of genetic diversity, while wild cotton is in the advantage of abundant genetic diversity, salt-tolerance, drought-tolerance and so on compared with upland cotton. This project is carried out to dissect the genetic basis of salt-tolerance in allotetraploid cotton. Quantitative trait loci (QTL) mapping in an interspecific hybridization and backcross population, transcriptomics analyses among different allotetraploid cotton, combined with genomic sequences of cotton as well as the elucidated aboitic response and regulation pathways in model organisms, were used to identify the genetic loci and candidate genes associated with salt-tolerance. And then functional molecular markers were developed from candidate genes for marker-assisted selection (MAS) breeding. Moreover, comparative transcriptomics analyses were utilized to probe the genetic diversity, expression differentiation and molecular evolution during domestication between allotetraploid cotton. The models of natural or artificial selection and expression of genes associated with abiotic stress will be revealed. And thus these may be useful as theoretical basis for improving abiotic stress tolerance in cultivated cotton by exploiting the genetic resources of wild cotton.

棉花是我国重要的纤维和油料作物，而随着“粮进棉退”现象的加剧，发展盐碱地植棉是保障我国棉花安全的重要策略。陆地棉是最主要的栽培种，但现有品种的遗传背景狭窄，而野生棉的遗传多样性丰富，有耐盐等优异基因源。本研究以异源四倍体棉花种间杂交-回交群体以及不同棉种盐胁迫下的转录组测序为基础，利用QTL定位和盐胁迫下棉种内表达差异分析，发掘出异源四倍体野生棉中控制耐盐性状的遗传位点，结合棉花现有基因组测序结果以及模式生物中相对明确的抗逆应答与信号转导途径，初步筛选出QTL区间内的候选基因，开发成功能标记，为将来棉花耐盐分子标记辅助育种奠定基础；同时通过棉种间比较转录组的分析方法，对异源四倍体棉花在驯化过程中与耐盐等抗逆性状相关基因的遗传多态性、表达变异与分子进化进行分析，初步揭示与抗逆相关基因的自然/人工选择及表达模式，为将来异源四倍体野生棉在栽培棉抗逆遗传改良中的应用提供重要的理论依据。

棉花是我国重要的纤维和油料作物，而随着“粮进棉退”现象的加剧，发展盐碱地植棉是保障我国棉花安全的重要策略。陆地棉是最主要的栽培种，但现有品种的遗传背景狭窄，而野生棉的遗传多样性丰富，有耐盐等优异基因源。本研究以异源四倍体棉花种间杂交-回交群体以及不同棉种盐胁迫下的转录组测序为基础，利用QTL定位和盐胁迫下棉种内表达差异分析，发掘出异源四倍体野生棉中控制耐盐性状的遗传位点，结合棉花现有基因组测序结果以及模式生物中相对明确的抗逆应答与信号转导途径，初步筛选出QTL区间内的候选基因，开发成功能标记，为将来棉花耐盐分子标记辅助育种提供参考；同时通过棉种间比较转录组的分析方法，对异源四倍体棉花在驯化过程中与耐盐等抗逆性状相关基因的遗传多态性、表达变异与分子进化进行分析，初步揭示与抗逆相关基因的自然/人工选择及表达模式，为将来异源四倍体野生棉在栽培棉抗逆遗传改良中的应用提供重要的理论依据。本研究通过再盐胁迫环境下对陆地棉、半野生棉、海岛棉和四倍体野生棉的转录组数据进行分析，通过筛选不同棉种间的直系同源基因进行耐盐选择驯化方面的研究分析，发现7个基因受到强烈的正向选择，并对这些基因在拟南芥中进行转化验证。通过在毛棉与陆地棉构建的F2:3群体中的QTL定位，一共得到11个在多环境下都能够重复检测的与盐胁迫相关的QTL，并发现大部分（10）QTL都位于Dt亚基因组上，通过与转录组数据相结合进行分析，发现一部分在盐胁迫下差异表达的基因位于QTL区间。