Xiong Hongchun, Li Yuting, Guo Huijun, Xie Yongdun, Zhao Linshu, Gu Jiayu, Zhao Shirong, Ding Yuping, Liu Luxiang
National Engineering Laboratory for Crop Molecular Breeding, National Center of Space Mutagenesis for Crop Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.
Front Plant Sci. 2021 Feb 23;12:628478. doi: 10.3389/fpls.2021.628478. eCollection 2021.
Agronomic traits such as heading date (HD), plant height (PH), thousand grain weight (TGW), and spike length (SL) are important factors affecting wheat yield. In this study, we constructed a high-density genetic linkage map using the Wheat55K SNP Array to map quantitative trait loci (QTLs) for these traits in 207 recombinant inbred lines (RILs). A total of 37 QTLs were identified, including 9 QTLs for HD, 7 QTLs for PH, 12 QTLs for TGW, and 9 QTLs for SL, which explained 3.0-48.8% of the phenotypic variation. Kompetitive Allele Specific PCR (KASP) markers were developed based on sequencing data and used for validation of the stably detected QTLs on chromosomes 3A, 4B and 6A using 400 RILs. A QTL cluster on chromosome 4B for PH and TGW was delimited to a 0.8 Mb physical interval explaining 12.2-22.8% of the phenotypic variation. Gene annotations and analyses of SNP effects suggested that a gene encoding protein Photosynthesis Affected Mutant 68, which is essential for photosystem II assembly, is a candidate gene affecting PH and TGW. In addition, the QTL for HD on chromosome 3A was narrowed down to a 2.5 Mb interval, and a gene encoding an R3H domain-containing protein was speculated to be the causal gene influencing HD. The linked KASP markers developed in this study will be useful for marker-assisted selection in wheat breeding, and the candidate genes provide new insight into genetic study for those traits in wheat.
抽穗期（HD）、株高（PH）、千粒重（TGW）和穗长（SL）等农艺性状是影响小麦产量的重要因素。在本研究中，我们使用小麦55K SNP芯片构建了高密度遗传连锁图谱，以定位207个重组自交系（RIL）中这些性状的数量性状位点（QTL）。共鉴定出37个QTL，包括9个HD的QTL、7个PH的QTL、12个TGW的QTL和9个SL的QTL，它们解释了3.0%-48.8%的表型变异。基于测序数据开发了竞争性等位基因特异性PCR（KASP）标记，并用于使用400个RIL验证在3A、4B和6A染色体上稳定检测到的QTL。4B染色体上PH和TGW的一个QTL簇被限定在一个0.8 Mb的物理区间内，解释了12.2%-22.8%的表型变异。基因注释和SNP效应分析表明，一个编码光合作用受影响突变体68蛋白的基因是影响PH和TGW的候选基因，该基因对光系统II组装至关重要。此外，3A染色体上HD的QTL被缩小到一个2.5 Mb的区间，推测一个编码含R3H结构域蛋白的基因是影响HD的因果基因。本研究中开发的连锁KASP标记将有助于小麦育种中的标记辅助选择，候选基因为小麦这些性状的遗传研究提供了新的见解。
