基于染色体置换系的普通野生稻耐盐性QTL定位

QTL Mapping Revealed Salt Tolerance Traits from Oryza rufipogon using Chromosome Segment Substitution Lines

本研究分别利用SSR标记、InDel标记以及简化基因组测序技术对一套以普通野生稻为供体亲本,9311为受体亲本的染色体置换系进行基因型鉴定,并通过对其不同生育期的耐盐性鉴定,共发掘2个与发芽期耐盐相关的QTL,13个与苗期耐盐性相关的QTL。其中与苗期存活率相关的QTL qSSR5.1、苗期耐盐等级相关的QTL qSSG5.1均被定位于同一位点,该位点对苗期存活率、苗期耐盐等级均具有增效作用,贡献率分别为6.36%、8.13%。在此QTL内包含与非生物胁迫相关基因OsDi19-1。经序列比对发现,OsDi19-1启动子区域在两亲本间存在较大差异,且受到盐胁迫时该基因表达量上升。同时,鉴定出水稻芽期耐盐的优异种质资源CSSL72、苗期耐盐的优异种质资源CSSL23、CSSL153,为水稻育种中耐盐性的改良提供了新的种质资源。

Within this study,a QTL mapping of salt tolerance was conducted by using a population of chromosome segment substitution lines(CSSLs),which were generated from common wild rice as donor parent and cultivated rice(9311)as receive parent.Genotyping for CSSLs were performed with types of markers(SSR,InD el and genotyping-by-sequencing markers).The phenotypic datasets were assessed by systemically evaluating the salt tolerance at different growth periods.As a result,two QTLs at germination stage and 13 QTLs at seedling stage were obtained.Among QTLs,qSSR5.1 and qSSG5.1 were found at the same locus,which synergistically contributed to the seedling survival rate(6.36%)and salt tolerance grade(8.13%).Within the target interval,one candidate gene OsDi19-1 which associated with abiotic stress was found.Sequence alignment showed an obvious sequence variation between 9311 and wild rice in the promoter region of OsDi19-1.Notably,the line CSSL72 showed a higher germination rate,while CSSL23 and CSSL153 exhibited higher seedling rates.A downregulation on gene expression was observed in CSSL23 and CSSL153,if relative to 9311 under salt treatment.Taken together,our data indicated that OsDi19-1 from wild rice might contribute to the salt tolerance,and these elite lines might become useful in future rice salt tolerance breeding.