Transcription factors ERF74/77/108/125 enhance thermotolerance in rice by regulating common and distinct heat-responsive gene expression

Abstract

Heat stress severely impacts crop productivity, necessitating the identification of key regulatory genes for improving thermotolerance. Here, we demonstrate that the rice nuclear-localized AP2/ERF transcription factors ERF74/77/108/125 function as critical regulators of heat stress responses. Loss-of-function mutant seedlings of ERF74/77 or ERF108/125 exhibit increased heat sensitivity, whereas overexpression of each ERF74, ERF77, ERF108 or ERF125 individually enhances thermotolerance, indicating their positive role in heat adaptation. These ERFs activate heat-responsive genes, with ERF74/77 and ERF108/125 sharing common targets while maintaining distinct regulatory networks. Mechanistically, ERF74/77/108/125 directly bind to the promoter of HsfA2c, a central heat shock transcription factor, and activate its expression. Genetic evidence confirms that HsfA2c is essential for mediating thermotolerance in rice. Our findings reveal a hierarchical regulatory module where ERF74/77/108/125 orchestrate heat stress responses by activating distinct and common downstream genes including HsfA2c, providing potential targets for engineering climate-resilient rice.