Exploring heat stress responses and heat tolerance in rice in the reproductive stage: A dual omics approach
Yusheng Guan, Yun Chen, Qianlong Huang, Y.X. He, Xianyong Li, Zichao Zhu, Ying Xiong, Jie Ouyang, Jiang Gang, Yi Zhang, Chutao Wang
Abstract
High temperatures significantly impact rice ( Oryza sativa L.) yield and quality during the reproductive growth stage. To elucidate key genes, metabolites, and key regulatory pathways associated with heat stress responses, we subjected three inbred rice varieties, one heat-tolerant variety (R28) and two heat-sensitive varieties (R18 and Q3B), to high-temperature treatments at the booting, flowering, and grain-filling stages. Through transcriptomic analysis, we identified 48, 148, and 31 genes that were commonly upregulated or downregulated in response to heat stress across the three developmental stages; these genes were differentially expressed between heat-tolerant and heat-sensitive varieties. Cluster analysis and gene annotation revealed key genes and transcription factors involved in heat perception and response, including a gene encoding a blue blue-light Inhibitor, a calmodulin gene potentially involved in heat stress signal transduction, and a unique negative regulatory HSP gene. Metabolomic analysis revealed that the increased abundance of the metabolites eicosatetraenoic acid and arachidonic acid was closely associated with heat tolerance. By performing transcriptomic and metabolomic analyses, we revealed that the flavonoid 3-hydroxylase gene at the booting stage; the fructose and mannose metabolism pathways and the metabolite mannitol at the flowering stage; and the α-linolenic acid metabolism pathway at the grain-filling stage are closely related to rice heat tolerance. These findings provide new insights into the mechanisms of rice heat tolerance and may guide the breeding of heat-resistant rice plants in the future.