Transcriptomic Reconfiguration of Signal Transduction and Energy Metabolism Pathways Under Prolonged Heat Stress During Flowering in <i>Brassica napus</i>

ABSTRACT Rapeseed is an essential source of edible oil, primarily cultivated in temperate regions worldwide. This crop exhibits a marked sensitivity to elevated temperatures, particularly during the stages preceding and following flowering. The ongoing challenges posed by global climate change and increasing temperatures significantly threaten its yield. It is essential to elucidate the dynamics of rapeseed's response to sustained heat stress (HS), especially during the flowering phase, to advance research on enhancing its heat tolerance. In the present study, we analysed transcriptomic modifications in rapeseed plants subjected to HS at 33°C, spanning from the pre‐flowering stage to the commencement of blooming. Our findings revealed that rapeseed produced diminutive flowers with nonviable pollen and exhibited a decline in pistil receptivity. Transcriptome analysis revealed that 5588 and 5994 genes were upregulated and downregulated, respectively. KEGG enrichment analysis demonstrated that these DEGs were linked to hormone signal transduction pathways, energy metabolism (including starch and sucrose metabolism and glutathione metabolism), and plant‐specific MAPK signalling pathways. Furthermore, genes encoding reactive oxygen species (ROS) scavenging enzymes and heat shock transcription factors were prominently expressed under HS conditions. This study provides foundational insights into the mechanisms underlying heat tolerance in rapeseed and holds significant implications for the genetic enhancement of heat‐tolerant rapeseed varieties.