QTL Mapping and Identification of Candidate Genes for Heat Tolerance at the Flowering Stage in Rice

Lei Chen; Qiang Wang; Maoyan Tang; Xiaoli Zhang; Yinghua Pan; Xinghai Yang; Guoqing Gao; Ronghua Lv; Wei Tao; Ligeng Jiang; Tianfeng Liang

doi:10.3389/fgene.2020.621871

QTL Mapping and Identification of Candidate Genes for Heat Tolerance at the Flowering Stage in Rice

Front Genet. 2021 Jan 22:11:621871. doi: 10.3389/fgene.2020.621871. eCollection 2020.

Authors

Lei Chen^{1

2}, Qiang Wang², Maoyan Tang², Xiaoli Zhang², Yinghua Pan², Xinghai Yang², Guoqing Gao², Ronghua Lv², Wei Tao², Ligeng Jiang¹, Tianfeng Liang²

Affiliations

¹ Key Laboratory of Crop Cultivation and Farming System, College of Agriculture, Guangxi University, Nanning, China.
² Guangxi Academy of Agricultural Sciences/Guangxi Key Laboratory of Rice Genetics and Breeding, Rice Research Institute, Nanning, China.

Abstract

High-temperature stress can cause serious abiotic damage that limits the yield and quality of rice. Heat tolerance (HT) during the flowering stage of rice is a key trait that can guarantee a high and stable yield under heat stress. HT is a complex trait that is regulated by multiple quantitative trait loci (QTLs); however, few underlying genes have been fine mapped and cloned. In this study, the F_2:3 population derived from a cross between Huanghuazhan (HHZ), a heat-tolerant cultivar, and 9311, a heat-sensitive variety, was used to map HT QTLs during the flowering stage in rice. A new major QTL, qHTT8, controlling HT was identified on chromosome 8 using the bulked-segregant analysis (BSA)-seq method. The QTL qHTT8 was mapped into the 3,555,000-4,520,000 bp, which had a size of 0.965 Mb. The candidate region of qHTT8 on chromosome 8 contained 65 predicted genes, and 10 putative predicted genes were found to be associated with abiotic stress tolerance. Furthermore, qRT-PCR was performed to analyze the differential expression of these 10 genes between HHZ and 9311 under high temperature conditions. LOC_Os08g07010 and LOC_Os08g07440 were highly induced in HHZ compared with 9311 under heat stress. Orthologous genes of LOC_Os08g07010 and LOC_Os08g07440 in plants played a role in abiotic stress, suggesting that they may be the candidate genes of qHTT8. Generally, the results of this study will prove useful for future efforts to clone qHTT8 and breed heat-tolerant varieties of rice using marker-assisted selection.

Keywords: BSA-seq; QTL; candidate gene; flowering stage; heat tolerance; rice.