Comparative analysis of IRE1s in plants: insights into heat stress adaptation in Triticum aestivum

The unfolded protein response (UPR) pathway serves as a crucial mechanism enabling plants to perceive, respond to, and shield themselves from adverse environmental conditions. Inositol-requiring enzyme 1 (IRE1) is one of the key players of the UPR, and resides in the endoplasmic reticulum (ER) within the cell. This study provides a comprehensive analysis of 195 IRE1 genes across 90 diverse plant species, with a focus on their identification and characterization.

To decipher the functions of IRE1 family members, we investigated the evolution and spread of IREs in plants and analysed their structural and localization characteristics. Our detailed cis-element analysis revealed unique IRE1 regulation patterns in different plant species. Furthermore, gene expression analysis revealed tissue-specific and heat stress-responsive expression patterns of TaIRE1s, which were subsequently confirmed via quantitative gene expression analysis. TaIRE1-6A was upregulated in response to dithiothreitol (DTT) treatment as well as heat stress. This finding suggests that IRE1 might play a role in linking the UPR pathway and the heat stress response (HSR).

Our findings provide a comprehensive understanding of the evolution and expansion of IRE1 genes in different plant species. These findings provide a foundation for further in-depth research on the functional diversity of IREs in nutritious crops following polyploidization. By linking the UPR with HSR, IRE1 could be a key contributor to wheat's resilience against heat stress. Additionally, this connection offers important insights for future functional studies in other crops. Thus, this knowledge could be used for engineering climate resilience in crops such as wheat.