College of Agronomy, Shanxi Agricultural University, Taigu, 030801, People's Republic of China.
Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, People's Republic of China.
Sci Rep. 2020 Dec 16;10(1):22060. doi: 10.1038/s41598-020-75778-z.
High vigor seeds have greater yield potential than those with low vigor; however, long-term storage leads to a decline in this trait. The objective of this study was to identify quantitative trait loci (QTLs) for seed vigor-related traits under artificial aging conditions using a high-density genetic linkage map of wheat (Triticum aestivum) and mine the related candidate genes. A doubled haploid population, derived from a cross between Hanxuan 10 × Lumai 14, was used as the experimental material. Six controlled-environment treatments were set up, i.e. the seeds were aged for 0, 24, 36, 48, 60, and 72 h at a high temperature (48 °C) and under high humidity (relative humidity 100%). Eight traits including seed germination percentage, germination energy, germination index, seedling length, root length, seedling weight, vigor index, and simple vigor index were measured. With the prolongation of artificial aging treatment, these traits showed a continuous downward trend and significant correlations were observed between most of them. A total of 49 additive QTLs for seed vigor-related traits were mapped onto 12 chromosomes (1B, 2D, 3A, 3B, 3D, 4A, 4D, 5A, 5B, 5D, 6D, and 7A); and each one accounted for 6.01-17.18% of the phenotypic variations. Twenty-five pairs of epistatic QTLs were detected on all chromosomes, except for 5D, 6A, and 7D, and each epistasis accounted for 7.35-26.06% of the phenotypic variations. Three additive QTL hot spots were found on chromosomes 5A, 5B, and 5D, respectively. 13 QTLs, QGEe5B, QGIe5B, QSLc5B, QSLd5B, QSLf5B, QRLd5B, QRLe5B, QRLf5B, QVId5B, QVIe5B, QVIf5B, QSVId5B, and QSVIe5B, were located in the marker interval AX-94643729 ~ AX-110529646 on 5B and the physical interval 707,412,449-710,959,479 bp. Genes including TRAESCS5B01G564900, TRAESCS5B01G564200, TRAESCS5B01G562600, TraesCS5B02G562700, TRAESCS5B01G561300, TRAESCS5B01G561400, and TRAESCS5B01G562100, located in this marker interval, were found to be involved in regulating the processes of carbohydrate and lipid metabolism, transcription, and cell division during the germination of aging seeds, thus they were viewed as candidate genes for seed viability-related traits. These findings provide the basis for the seed-based cloning and functional identification of related candidate genes for seed vigor.
高活力种子比低活力种子具有更大的产量潜力；然而，长期储存会导致这种特性下降。本研究旨在利用小麦（Triticum aestivum）高密度遗传图谱，在人工老化条件下鉴定与种子活力相关性状的数量性状位点（QTL），并挖掘相关候选基因。以 Hanxuan 10 × Lumai 14 杂交产生的双单倍体群体为实验材料。设置了 6 个受控环境处理，即在高温（48°C）和高湿度（相对湿度 100%）下，种子老化 0、24、36、48、60 和 72 小时。测量了包括种子发芽率、发芽势、发芽指数、幼苗长度、根长、幼苗重量、活力指数和简单活力指数在内的 8 个性状。随着人工老化处理的延长，这些性状呈持续下降趋势，且大多数性状之间存在显著相关性。共在 12 条染色体（1B、2D、3A、3B、3D、4A、4D、5A、5B、5D、6D 和 7A）上定位到与种子活力相关性状的 49 个加性 QTL；每个 QTL 解释 6.01-17.18%的表型变异。在所有染色体上检测到 25 对上位性 QTL，除了 5D、6A 和 7D 外，每个上位性解释 7.35-26.06%的表型变异。在染色体 5A、5B 和 5D 上分别发现了 3 个加性 QTL 热点。在 5B 号染色体的标记区间 AX-94643729 到 AX-110529646 之间，以及物理区间 707,412,449-710,959,479 bp 之间，定位到 13 个 QTL，包括 QGEe5B、QGIe5B、QSLc5B、QSLd5B、QSLf5B、QRLd5B、QRLe5B、QRLf5B、QVId5B、QVIe5B、QVIf5B、QSVId5B 和 QSVIe5B。区间内的基因包括 TRAESCS5B01G564900、TRAESCS5B01G564200、TRAESCS5B01G562600、TraesCS5B02G562700、TRAESCS5B01G561300、TRAESCS5B01G561400 和 TRAESCS5B01G562100，这些基因参与调节老化种子发芽过程中的碳水化合物和脂质代谢、转录和细胞分裂等过程，因此被认为是与种子活力相关性状的候选基因。这些发现为基于种子的克隆和相关候选基因的功能鉴定提供了基础。
