HsfA7 coordinates the transition from mild to strong heat stress response by controlling the activity of the master regulator HsfA1a in tomato

Cell Rep. 2022 Jan 11;38(2):110224. doi: 10.1016/j.celrep.2021.110224.


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. We identify tomato HsfA7 as 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.

Keywords: Solanum lycopersicum; acclimation; alternative splicing; heat stress; heat stress response; protein isoforms; temperature; transcription.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acclimatization
  • Arabidopsis
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • DNA-Binding Proteins / metabolism
  • Gene Expression / genetics
  • Gene Expression Regulation, Plant / genetics
  • Heat Shock Transcription Factors / genetics*
  • Heat Shock Transcription Factors / metabolism
  • Heat-Shock Proteins / metabolism
  • Heat-Shock Response / genetics
  • Hot Temperature
  • Plant Proteins / genetics
  • Plants, Genetically Modified / metabolism
  • Solanum lycopersicum / genetics*
  • Solanum lycopersicum / metabolism
  • Thermotolerance / genetics
  • Trans-Activators / genetics*
  • Trans-Activators / metabolism
  • Transcription Factors / metabolism


  • AT3G63350 protein, Arabidopsis
  • Arabidopsis Proteins
  • DNA-Binding Proteins
  • Heat Shock Transcription Factors
  • Heat-Shock Proteins
  • HsfA1a protein, Arabidopsis
  • Plant Proteins
  • Trans-Activators
  • Transcription Factors