Transcriptome analysis of two rice cultivars highlights the role of auxin- and JA-responsive genes under heat stress

Elevated temperatures pose a significant threat to rice crops, necessitating the elucidation of the regulatory mechanisms underlying the response of rice to heat stress. Such comprehension is vital for the cultivation of rice cultivars that can withstand high temperatures, thereby enhancing secure and sustainable food production. In this study, we discovered a rice near-isogenic line, S49, in the Sasanishiki (Sa) genetic background that is resistant to heat stress. Compared with the heat-susceptible cultivar Sa, S49 demonstrated superior growth under heat stress conditions of 43 ℃ for three days. Through a comparative analysis of plant hormones and transcriptomes between these two lines, we observed that S49 presented relatively high levels of indole-3-acetic acid (IAA) and relatively low levels of jasmonic acids (JAs) under heat stress for 24 h, which was consistent with our transcriptome analysis. The findings revealed that under heat stress, the JA and IAA pathways exhibit distinct regulatory patterns between Sa and S49, suggesting that these two signaling pathways may independently mediate different stress resistance strategies. These results shed new light on the mechanisms of high-temperature tolerance in rice and lay the groundwork for future genetic research into this tolerance.