Plants respond to higher temperatures by the action of heat stress (HS) transcription factors (Hsfs), which control the onset, early response, and long-term acclimation to HS. Members of the HsfA1 subfamily, such as tomato HsfA1a, are the central regulators of HS response, and their activity is fine-tuned by other Hsfs.
This research identifies tomato HsfA7 as a capacitor of HsfA1a during the early HS response. Upon a mild temperature increase, HsfA7 is induced in an HsfA1a-dependent manner. The subsequent interaction of the two Hsfs prevents the stabilization of HsfA1a resulting in a negative feedback mechanism. Under prolonged or severe HS, HsfA1a and HsfA7 complexes stimulate the induction of genes required for thermotolerance.
Therefore, HsfA7 exhibits a co-repressor mode at mild HS by regulating HsfA1a abundance to moderate the upregulation of HS-responsive genes. HsfA7 undergoes a temperature-dependent transition toward a co-activator of HsfA1a to enhance the acquired thermotolerance capacity of tomato plants.
Read the complete research at www.researchgate.net.
Mesihovic, Anida & Ullrich, Sarah & Rosenkranz, Remus & Gebhardt, Philipp & Bublak, Daniela & Eich, Hannah & Weber, Daniel & Berberich, Thomas & Scharf, Klaus-Dieter & Schleiff, Enrico & Fragkostefanakis, Sotirios. (2022). HsfA7 coordinates the transition from mild to strong heat stress response by controlling the activity of the master regulator HsfA1a in tomato. Cell Reports. 38. 110224. 10.1016/j.celrep.2021.110224.
