Anther Transcriptome Analysis of Two Heat Tolerance-Differentiated Indica Rice Restorer Lines Reveals the Importance of Non-Structural Carbohydrates and ATP in the Regulation of Heat Tolerance

Screening and breeding more resistant heat stress restorer lines represent an effective approach to addressing the decline in hybrid rice seed production caused by heat stress (HS). However, the molecular mechanisms affecting the differences in the heat resistance of anthers under HS remain unclear. This study compared the gene expression patterns of two hybrid rice restorer lines with differing heat resistances under HS and discusses the mechanisms of the heat response in rice. Under heat stress, 247 DEGs were co-expressed across varieties and were involved in biological processes such as protein processing and carbon metabolism, with heat shock proteins being the most ubiquitous. Interestingly, a substantial enrichment of genes related to non-structural carbohydrates and ATP was observed among the unique DEGs in R996 and R4628. Simultaneously, the contents of non-structural carbohydrates and ATP levels in the young spikes of R996 were significantly higher than those in R4628. This suggests that starch, soluble sugars and ATP play significant roles in heat tolerance during the flowering stage of rice. Overall, this study provides novel insights into the molecular mechanisms underlying heat stress resistance in indica rice restorer lines and informs future strategies for the genetic improvement of heat tolerance in these varieties.