中国农业科学2017，Vol.50Issue(1)：131-141,11.DOI:10.3864/j.issn.0578-1752.2017.01.012
西瓜枯萎病生理小种1抗性QTL精细定位与InDel标记开发
Fine-Mapping of QTL and Development of InDel Markers for Fusarium oxysporum Race 1 Resistance in Watermelon
摘要
Abstract
[Objective]In order to clone gene and provide technical supports for molecular assisted breeding for Fusarium oxysporum race 1 resistance in watermelon, combined QTL mapping and re-sequencing of parental lines, tightly linked InDel (insertion/deletion) markers were developed and finally the major QTL was fine mapped.[Method]Firstly, genome-wide QTL scanning for Fusarium oxysporum race 1 resistance in an F2 segregating population derived from a cross between the cultivated resistance female parent 'ZXG01478' and the cultivated susceptible male parent '14CB11' was performed using the composite interval mapping program of the WinQTL cartographer 2.5 software. Secondly, InDel markers were developed based on the InDel information on the QTL region by re-sequencing of parental lines. Finally, fine-mapping, genetic map and QTL analysis were re-performed using developed InDel markers. Moreover, a total of 130 watermelon germplasms with different Fusarium oxysporum race 1 resistances were used to perform validation analysis.[Result]In the F2 population, the frequency distribution of susceptible plant rate deviated from normality and appeared to have a discontinuous bimodal pattern. Moreover, the ratio of resistance to susceptible to Fusarium oxysporum race 1 corresponded to the expected 3﹕1 segregation for a single-locus inheritance (χ2=0.52, P=0.47). Preliminary QTL mapping only identified one QTL (fon1) for Fusarium oxysporum race 1 resistance on LG1, which showed peak LOD of 26.05 and could explain 80.18% of the phenotype variation. The confidence intervals of fon1 was 193333-2775577 bp on chromosome 1 (physical map). A total of 19 InDels with length more than 20 bp were detected on QTL region by re-sequence analysis. Of these, 12 showed polymorphism between two parents. Six primer pairs were selected to genotype in the F2 population. Using four recombinant lines in F2 population, preliminary fine-mapping narrowed the QTL region to upstream of InDel2_fon1. QTL re-analysis showed that one of the new developed markers (InDel1_fon1) located on the peak QTL region, which showed peak LOD of 31.65 and could explain 91.46% of the phenotype variation. The genotype of InDel1_fon1 and 7716_fon were consistent with each other for all of the 130 watermelon germplasms, and there was a relative high coincidence rate (70.8%) of genotype and phenotype. Target QTL region was narrowed to physical distance of 246 kb using new developed InDel markers and flanking SNP markers. [Conclusion] Major QTL (fon1) confirmed the existence of Fusarium oxysporum race 1 resistance gene Fon-1 and was finely-mapped to a relative small region. One of the new developed markers, InDel1_fon1, was tightly linked to gene Fon-1, which could better applied in molecular assisted breeding for resistance to Fusarium wilt in cultivated watermelon.关键词
西瓜/枯萎病生理小种1/QTL精细定位/InDel标记Key words
watermelon (Citrullus lanatus)/Fusarium oxysporum race 1 resistance/QTL fine-mapping/InDel marker引用本文复制引用
李娜,王吉明,尚建立,李楠楠,徐永阳,马双武..西瓜枯萎病生理小种1抗性QTL精细定位与InDel标记开发[J].中国农业科学,2017,50(1):131-141,11.基金项目
国家现代农业产业技术体系建设专项(CARS-26-01)、国家农作物种质资源平台(NICGR2015-016)、中国农业科学院科技创新工程专项经费(CAAS-ASTIP-2016-ZFRI) （CARS-26-01）
