水稻柱头外露率主效QTL qTSE4 的定位

Mapping of QTL qTSE4 for stigma exsertion rate in rice

[目的]柱头外露率是杂交水稻制种的一个重要指标,本研究旨在检测控制水稻柱头外露率QTL及精细定位相关基因。[方法]以低柱头外露率粳稻品种‘02428’和高柱头外露率亲本ZH464配组的F 2群体进行QTL位点检测,在目标区域内利用分子标记筛选杂合单株,对连续自交获得的F 2:3和F 3:4群体进行多年稳定QTL位点定位,同时利用BSA-seq技术对F 3:4群体进行柱头外露率QTL定位和候选基因序列分析。[结果]相关性分析结果显示单柱头外露率、双柱头外露率和总柱头外露率这3个性状存在极显著的相关性。以总柱头外露率作为表型数据,利用已构建的覆盖全基因组分子连锁遗传图谱进行QTL定位,检测到第2和4染色体上的2个位点:qTSE2和qTSE4,选择贡献率大的qTSE4位点进行后续研究,该位点在F 2:3和F 3:4群体中被重复检测到。结合BSA-seq测序结果,在qTSE4位点区间内筛选到2个存在差异的基因。[结论]qTSE4位点作为柱头外露相关的主效QTL位点,可进行后续的精细定位,筛选到的2个候选基因有待进一步转基因功能验证。

[Objectives]Stigma exsertion rate is an important determinant of outcrossing in hybrid rice seed production.The purpose of this study was to detect quantitative trait loci(QTL)controlling stigma exsertion rate and fine mapping related genes in rice.[Methods]In this study,an F 2 population derived from japonica rice variety‘02428’with low stigma exsertion rate and parent ZH464 with high stigma exsertion rate was used for preliminary detection of QTL.Molecular markers were used to screen heterozygous individual plants in the target region to obtain F 2:3 and F 3:4 populations by continuous selfing for multi-year stable QTL mapping.At the same time,BSA-seq technology was used to analyze gene mapping and candidate gene sequence of the target region.[Results]The results of correlation analysis showed that there was a very significant correlation among the three traits of single stigma exsertion rate,double stigma exsertion rate and total stigma exsertion rate.In this study,the total stigma exsertion rate was used as phenotypic data,and the constructed genome-wide molecular linkage genetic map was used for QTL mapping.Two loci,qTSE2 and qTSE4,were detected on chromosomes 2 and 4,respectively.qTSE4 with high contribution rate was selected as the target locus for follow-up study.This locus was repeatedly detected in the F 2:3 and F 3:4 planting population.Based on BSA-seq result,two genes with differences were screened in the qTSE4 locus interval.[Conclusions]qTSE4 locus as the major QTL related to stigma exsertion rate,can be used for subsequent fine-mapping.The two screened candidate genes need to be further verified by transgenic experiment.