一个控制水稻分蘖角度主效QTL qTAC8的图位克隆及驯化分析

Rice tiller angle is an important agronomic trait that contributes to crop production and plays a vital role in high yield breeding. A recombinant inbred line (RIL) population derived from the cross of a glabrous tropical japonica rice D50 and an indica rice HB277, was used to investigate quantitative trait loci (QTLs) controlling rice tiller angle. Two major QTLs, qTAC8 and qTAC9, were detected. qTAC8 is a new locus, using a BC2F2 population, qTAC8 was mapped to a 16.5 cM region between markers RM7049 and RM23175. Position of qTAC8 was narrowed to a 92 kb DNA region by two genetic segregating populations(BC2F5 and BC2F7). Within the interval, 7 ORFs were detected , then ORF7 was regarded as a candidate gene according to genomic sequencing and qRT-PCR analysis. In this proposed study, we will conduct functional complementary test of TAC8. The temporal and spatial expression patterns and protein subcellular localization of TAC8 will also be analyzed; In order to elucidate the characteristics of origin and domestication of TAC8, genotype and haplotype analysis will be carried based on function marker and sequencing. The results of this project will provide new genetic resources for breeding rice varieties with appropriate compact plant architecture. And lay a fundamental foundation for elucidating genetic mechanism of tiller angle.

分蘖角度是构建水稻理想株型的重要农艺性状，在水稻高产育种中发挥着重要作用。以光身稻品种D50和籼稻品种HB277为亲本构建的RIL群体进行分蘖角度QTLs定位，检测到两个控制分蘖角度的主效QTL qTAC8与qTAC9,其中qTAC8是一个新的位点。构建BC2F2群体将qTAC8定位在RM7049和RM23175之间16.5 cM的区间内，利用BC2F5和BC2F7两个大的分离群体将qTAC8定位在一个92 Kb的区间内；该区间内有7个ORFs，测序以及Real time PCR分析发现ORF7可能是qTAC8的候选基因。本研究拟通过转基因验证TAC8的功能，同时分析其时空表达、亚细胞定位特性；并利用功能标记与基因测序分析不同水稻品种TAC8的基因型，分析其起源与驯化特征。本研究结果将为选育株型紧凑度适中的水稻品种提供新基因资源，也将为研究分蘖角度的遗传机理奠定基础。