Ravikiran K T, Gopala Krishnan S, Abhijith K P, Bollinedi H, Nagarajan M, Vinod K K, Bhowmick P K, Pal Madan, Ellur R K, Singh A K
Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, India.
Rice Breeding and Genetics Research Centre, ICAR-IARI, Aduthurai, India.
Front Genet. 2022 May 10;13:876522. doi: 10.3389/fgene.2022.876522. eCollection 2022.
Temperature rise predicted for the future will severely affect rice productivity because the crop is highly sensitive to heat stress at the reproductive stage. Breeding tolerant varieties is an economically viable option to combat heat stress, for which the knowledge of target genomic regions associated with the reproductive stage heat stress tolerance (RSHT) is essential. A set of 192 rice genotypes of diverse origins were evaluated under natural field conditions through staggered sowings for RSHT using two surrogate traits, spikelet fertility and grain yield, which showed significant reduction under heat stress. These genotypes were genotyped using a 50 k SNP array, and the association analysis identified 10 quantitative trait nucleotides (QTNs) for grain yield, of which one QTN () was consistent across the different models used. Only two out of 10 MTAs coincided with the previously reported QTLs, making the remaing eight novel. A total of 22 QTNs were observed for spikelet fertility, among which was consistently found across three models. Of the QTNs identified, seven coincided with previous reports, while the remaining QTNs were new. The genes near the QTNs were found associated with the protein-protein interaction, protein ubiquitination, stress signal transduction, and so forth, qualifying them to be putative for RSHT. An expression analysis revealed the predominant expression of genes identified for spikelet fertility in reproductive organs. Further validation of the biological relevance of QTNs in conferring heat stress tolerance will enable their utilization in improving the reproductive stage heat stress tolerance in rice.
预计未来的气温上升将严重影响水稻生产力，因为该作物在生殖阶段对热应激高度敏感。培育耐热品种是应对热应激的一种经济可行的选择，为此，了解与生殖阶段热应激耐受性（RSHT）相关的目标基因组区域至关重要。通过交错播种，利用两个替代性状——小穗育性和籽粒产量，在自然田间条件下对一组192个不同来源的水稻基因型进行了RSHT评估，这两个性状在热应激下均显著降低。使用50k SNP阵列对这些基因型进行基因分型，关联分析确定了10个与籽粒产量相关的数量性状核苷酸（QTN），其中一个QTN（）在使用的不同模型中是一致的。10个显著关联标记（MTA）中只有两个与先前报道的QTL一致，其余8个是新的。共观察到22个与小穗育性相关的QTN，其中一个在三个模型中均一致被发现。在鉴定出的QTN中，有7个与先前的报道一致，其余的QTN是新的。发现QTN附近的基因与蛋白质-蛋白质相互作用、蛋白质泛素化、应激信号转导等有关，这使它们有资格被认为与RSHT相关。一项表达分析揭示了为小穗育性鉴定出的基因在生殖器官中的主要表达。进一步验证QTN在赋予热应激耐受性方面的生物学相关性，将使其能够用于提高水稻生殖阶段的热应激耐受性。
