Luo Tao, Zhang Yuting, Zhang Chunni, Nelson Matthew N, Yuan Jinzhan, Guo Liang, Xu Zhenghua
MOA Key Lab. of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River/College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
Plants (Basel). 2021 Feb 24;10(3):426. doi: 10.3390/plants10030426.
Low temperature inhibits rapid germination and successful seedling establishment of rapeseed ( L.), leading to significant productivity losses. Little is known about the genetic diversity for seed vigor under low-temperature conditions in rapeseed, which motivated our investigation of 13 seed germination- and emergence-related traits under normal and low-temperature conditions for 442 diverse rapeseed accessions. The stress tolerance index was calculated for each trait based on performance under non-stress and low-temperature stress conditions. Principal component analysis of the low-temperature stress tolerance indices identified five principal components that captured 100% of the seedling response to low temperature. A genome-wide association study using ~8 million SNP (single-nucleotide polymorphism) markers identified from genome resequencing was undertaken to uncover the genetic basis of seed vigor related traits in rapeseed. We detected 22 quantitative trait loci (QTLs) significantly associated with stress tolerance indices regarding seed vigor under low-temperature stress. Scrutiny of the genes in these QTL regions identified 62 candidate genes related to specific stress tolerance indices of seed vigor, and the majority were involved in DNA repair, RNA translation, mitochondrial activation and energy generation, ubiquitination and degradation of protein reserve, antioxidant system, and plant hormone and signal transduction. The high effect variation and haplotype-based effect of these candidate genes were evaluated, and high priority could be given to the candidate genes , , , and in further study. These findings should be useful for marker-assisted breeding and genomic selection of rapeseed to increase seed vigor under low-temperature stress.
低温抑制油菜（L.）种子的快速萌发和成功成苗，导致显著的产量损失。对于油菜在低温条件下种子活力的遗传多样性知之甚少，这促使我们对442份不同油菜种质在正常和低温条件下的13个与种子萌发和出土相关的性状进行研究。根据非胁迫和低温胁迫条件下的表现，计算每个性状的胁迫耐受指数。对低温胁迫耐受指数进行主成分分析，确定了五个主成分，它们涵盖了幼苗对低温反应的100%。利用从基因组重测序中鉴定出的约800万个单核苷酸多态性（SNP）标记进行全基因组关联研究，以揭示油菜种子活力相关性状的遗传基础。我们检测到22个与低温胁迫下种子活力胁迫耐受指数显著相关的数量性状位点（QTL）。对这些QTL区域中的基因进行仔细研究，确定了62个与种子活力特定胁迫耐受指数相关的候选基因，其中大多数参与DNA修复、RNA翻译、线粒体激活和能量生成、蛋白质储备的泛素化和降解、抗氧化系统以及植物激素和信号转导。评估了这些候选基因的高效应变异和基于单倍型的效应，在进一步研究中可以优先考虑候选基因 、 、 、 和 。这些发现对于油菜的标记辅助育种和基因组选择以提高低温胁迫下的种子活力应该是有用的。
