State Key Laboratory of Agrobiotechnology/Beijing Key Laboratory of Crop Genetic Improvement, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China.
Biotechnology and Genetic Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming, China.
Plant Biotechnol J. 2020 Dec;18(12):2491-2503. doi: 10.1111/pbi.13424. Epub 2020 Jun 24.
Genetic studies on cold tolerance at the reproductive stage in rice could lead to significant reductions in yield losses. However, knowledge about the genetic basis and adaptive differentiation, as well as the evolution and utilization of the underlying natural alleles, remains limited. Here, 580 rice accessions in two association panels were used to perform genome-wide association study, and 156 loci associated with cold tolerance at the reproductive stage were identified. Os01g0923600 and Os01g0923800 were identified as promising candidate genes in qCTB1t, a major associated locus. Through population genetic analyses, 22 and 29 divergent regions controlling cold adaptive differentiation inter-subspecies (Xian/Indica and Geng/Japonica) and intra-Geng, respectively, were identified. Joint analyses of four cloned cold-tolerance genes showed that they had different origins and utilizations under various climatic conditions. bZIP73 and OsAPX1 differentiating inter-subspecies evolved directly from wild rice, whereas the novel mutations CTB4a and Ctb1 arose in Geng during adaptation to colder climates. The cold-tolerant Geng accessions have undergone stronger selection under colder climate conditions than other accessions during the domestication and breeding processes. Additive effects of dominant allelic variants of four identified genes have been important in adaptation to cold in modern rice varieties. Therefore, this study provides valuable information for further gene discovery and pyramiding breeding to improve cold tolerance at the reproductive stage in rice.
对水稻生殖阶段耐冷性的遗传研究可能会显著降低产量损失。然而，关于遗传基础和适应性分化，以及潜在自然等位基因的进化和利用，人们的了解仍然有限。在这里，利用两个关联面板中的 580 个水稻品系进行了全基因组关联研究，鉴定出了 156 个与生殖阶段耐冷性相关的位点。在主要关联位点 qCTB1t 中，鉴定到 Os01g0923600 和 Os01g0923800 为有前途的候选基因。通过群体遗传分析，鉴定到了控制亚种间（籼稻/粳稻和光壳稻/爪哇稻）和种内（粳稻）冷适应分化的 22 和 29 个分歧区域。对四个克隆的耐冷基因的联合分析表明，它们在不同的气候条件下具有不同的起源和利用方式。bZIP73 和 OsAPX1 是亚种间分化的直接从野生稻进化而来的，而新的突变 CTB4a 和 Ctb1 则是在光壳稻适应更冷的气候时在粳稻中产生的。在驯化和选育过程中，耐冷的粳稻品系在较冷的气候条件下经历了比其他品系更强的选择。四个已鉴定基因的显性等位变异的累加效应在现代水稻品种适应寒冷方面非常重要。因此，这项研究为进一步发现基因和进行基因聚合育种以提高水稻生殖阶段的耐冷性提供了有价值的信息。
