水稻粒形基因GW8的功能标记开发和单体型鉴定

Development of Functional Markers and Identification of Haplotypes for Rice Grain Shape Gene GW8

水稻粒形性状包含粒长、粒宽、粒厚和长宽比,是一类影响水稻产量和品质的重要性状。基于基因GW8序列分析,在该基因启动子区10 bp的Indel和第3外显子A/C和T/G的2个变异位点分别开发了功能标记,并将其用于294份水稻微核心种质和2007—2013年江苏省审定的65份粳稻品种的基因型鉴定。研究结果表明这3个变异位点的等位变异对主要的粒形性状有着显著或极显著的影响;其在水稻微核心种质存在的8种单体型对水稻粒形性状有着极显著的影响,其中分别有126、85和58个代表品种的Hap3、Hap6和Hap1是最主要的单体型,单体型Hap7对应水稻籽粒的粒长最长、长宽比最大、千粒重最大;而江苏省审定的粳稻品种中仅发现分别有63个和2个代表品种的单体型是Hap6和Hap2。这些研究结果为水稻产量和品质育种中充分利用基因GW8的优异等位基因或单体型奠定了基础。

Rice grain shape including grain length, grain width, grain thickness, and grain length-to-width ratio is a major character affecting rice yield and quality. On the basis of the alignment of gene GW8 genomic DNA sequence, three functional markers were developed on the 10-bp indel in promoter region and two missense polymorphism sites（A/C and T/G） in the exon3, respectively. Subsequently the markers were used to identify the genotypes of gene GW8 in the 294 accessions of rice mini-core collection and 65 japonica varieties certificated in Jiangsu province from 2007 to 2013. We found that the allelic variations of the three target loci had significant or very significant effects on most traits of grain shape. On the bais of the three variation sites of gene GW8, eight haplotypes（combinations） were found to have very significant effect on the four grain shape traits in the rice mini-core collection. The main haplotypes were Hap3, Hap6, and Hap1, contained in 126, 85, and 58 representative varieties, respectively; Hap7 has the most strongest effect on grain length, ratio of length to width and 1000-grain weight. While the only two haplotypes, Hap6 and Hap2, contained in 63 and 2 japonica varieties certificated in Jiangsu provice, respectively. The results paved a way to apply the useful allelic variations or haplotypes of gene GW8 in rice yield and quality breeding programs.