Molecular Hubs of Plant Heat Stress Memory: Structure, Function, and Regulatory Mechanisms of HSFs

Global warming is associated with an increased frequency and intensity of heat waves, which severely threaten crop production and sustainable agriculture. As sessile organisms, plants evolved complex heat stress memory mechanisms to cope with recurring heat waves. Heat shock transcription factors (HSFs) are at the core of plant heat stress responses and memory. They regulate basal thermotolerance, acquired thermotolerance, and the maintenance of acquired thermotolerance. These processes involve multiple mechanisms, including temperature perception, activation of heat shock protein expression, and integration of hormonal and epigenetic signals. Here, we review the pivotal role HSFs play in the formation of heat stress memory, their structural characteristics, functional differentiation, and signal perception and transcriptional regulatory mechanisms. We further discuss the functional conservation and the diversity of HSFs across multiple species—for instance, HSFA2 acts as a conserved regulator of heat stress memory in Arabidopsis, tomato, wheat, and barley—and outline future research directions, including the functional characterization of heat shock transcription factor (HSF) subfamilies, investigation of their roles under stress combination, and strategies to balance stress tolerance with growth and development. We hope that our review will provide a theoretical foundation for the genetic improvement of crop thermotolerance as well as contribute to efforts directed at ensuring food security in the face of climate change.