Sidhu Jagdeep Singh, Singh Dilkaran, Gill Harsimardeep Singh, Brar Navreet Kaur, Qiu Yeyan, Halder Jyotirmoy, Al Tameemi Rami, Turnipseed Brent, Sehgal Sunish Kumar
Department of Agronomy, Horticulture & Plant Science, South Dakota State University, Brookings, SD, United States.
Department of Biology and Microbiology, South Dakota State University, Brookings, SD, United States.
Front Genet. 2020 Feb 5;10:1345. doi: 10.3389/fgene.2019.01345. eCollection 2019.
Successful seedling establishment depends on the optimum depth of seed placement especially in drought-prone conditions, providing an opportunity to exploit subsoil water and increase winter survival in winter wheat. Coleoptile length is a key determinant for the appropriate depth at which seed can be sown. Thus, understanding the genetic basis of coleoptile length is necessary and important for wheat breeding. We conducted a genome-wide association study (GWAS) using a diverse panel of 298 winter wheat genotypes to dissect the genetic architecture of coleoptile length. We identified nine genomic regions associated with the coleoptile length on seven different chromosomes. Of the nine genomic regions, five have been previously reported in various studies, including one mapped to previously known region. Three novel quantitative trait loci (QTLs), , , and were identified in our study. has a large substitution effect which is comparable to 's effect and could be used to compensate for the negative effect of on coleoptile length. In total, the nine QTLs explained 59% of the total phenotypic variation. Cultivars 'Agate' and 'MT06103' have the longest coleoptile length and interestingly, have favorable alleles at nine and eight coleoptile loci, respectively. These lines could be a valuable germplasm for longer coleoptile breeding. Gene annotations in the candidate regions revealed several putative proteins of specific interest including cytochrome P450-like, expansins, and phytochrome A. The QTLs for coleoptile length linked to single-nucleotide polymorphism (SNP) markers reported in this study could be employed in marker-assisted breeding for longer coleoptile in wheat. Thus, our study provides valuable insights into the genetic and molecular regulation of the coleoptile length in winter wheat.
成功的幼苗建立取决于种子播种的最佳深度，尤其是在易干旱的条件下，这为利用土壤下层水分和提高冬小麦冬季存活率提供了机会。胚芽鞘长度是决定种子可播种适宜深度的关键因素。因此，了解胚芽鞘长度的遗传基础对于小麦育种来说是必要且重要的。我们使用由298个冬小麦基因型组成的多样化群体进行了全基因组关联研究（GWAS），以剖析胚芽鞘长度的遗传结构。我们在七条不同的染色体上鉴定出了九个与胚芽鞘长度相关的基因组区域。在这九个基因组区域中，有五个在之前的各种研究中已有报道，其中一个定位到了先前已知的区域。在我们的研究中鉴定出了三个新的数量性状位点（QTL），即 、 和 。 具有较大的替代效应，与 的效应相当，可用于补偿 对胚芽鞘长度的负面影响。这九个QTL总共解释了59%的表型变异。品种“玛瑙”和“MT06103”的胚芽鞘长度最长，有趣的是，它们分别在九个和八个胚芽鞘位点上具有有利等位基因。这些品系可能是培育更长胚芽鞘的宝贵种质资源。候选区域的基因注释揭示了几种特别感兴趣的推定蛋白，包括细胞色素P450样蛋白、扩张蛋白和光敏色素A。本研究报道的与单核苷酸多态性（SNP）标记连锁的胚芽鞘长度QTL可用于小麦更长胚芽鞘的标记辅助育种。因此，我们的研究为冬小麦胚芽鞘长度的遗传和分子调控提供了有价值的见解。
