Identification Of Rice Continuous Heat-resistance Candidate Genes Based On Integrating Meta-QTL And RNA-seq Analysis

Due to global warming,extreme high temperature weather in summer is increasing,which is a serious threat to the safe production of rice and The Food Security Strategy in our country.Therefore,it becomes more important to mine the tolerance genes of rice and cultivate heat-tolerant rice.In this study,a meta-analysis was carried out on 170 QTL related to heat tolerance of rice in 27 independent studies.35 Meta-QTL were identified on rice chromosomes,with an average interval distance of 1.74 Mb,containing a total of6795 interval genes.Among them,39 genes have been reported to be associated with heat-tolerance of rice,including heat-tolerant genes TT3.1 and TT3.2 with natural variation.Although Meta analysis has reduced the confidence interval of QTL in the original study,it still contains a large number of genes.Therefore,we further combine Meta-QTL with RNA-seq analysis to narrow the range of candidate genes for heat tolerance in rice.In addition,most of the cloned rice heat tolerance genes play a role at the seedling stage,and rice is easily damaged by high temperature stress at the heading stage,so the transcriptome data of rice under heat stress at seedling stage and heading stage are selected for differential expression analysis,and then the rice heat tolerance Meta-QTL and RNA-seq are integrated and analyzed.It is found that 77 genes are located in the heat-tolerant Meta-QTL interval.In addition,the of persistent heat-tolerant candidate genes were expressed significantly in response to heat stress at seedling stage and heading stage.Among these candidate genes,there are not only HSP101 which has been proved to be heat-tolerant genes,but also genes related to rice homeostasis and physiological morphology under heat stress,and some genes have not been studied yet,which need to be further explored in the future.These genes found in this study may continuously respond to heat stress during the growth and development of rice,and are of great significance for the breeding of heat-tolerant rice varieties.