Heat Shock Signaling in Land Plants: From Plasma Membrane Sensing to the Transcription of Small Heat Shock Proteins.

Baptiste Bourgine,Anthony Guihur

doi:10.3389/fpls.2021.710801

Abstract

Heat stress events are major factors limiting crop productivity. During summer days, land plants must anticipate in a timely manner upcoming mild and severe temperature. They respond by accumulating protective heat-shock proteins (HSPs), conferring acquired thermotolerance. All organisms synthetize HSPs; many of which are members of the conserved chaperones families. This review describes recent advances in plant temperature sensing, signaling, and response. We highlight the pathway from heat perception by the plasma membrane through calcium channels, such as cyclic nucleotide-gated channels, to the activation of the heat-shock transcription factors (HSFs). An unclear cellular signal activates HSFs, which act as essential regulators. In particular, the HSFA subfamily can bind heat shock elements in HSP promoters and could mediate the dissociation of bound histones, leading to HSPs transcription. Although plants can modulate their transcriptome, proteome, and metabolome to protect the cellular machinery, HSP chaperones prevent, use, and revert the formation of misfolded proteins, thereby avoiding heat-induced cell death. Remarkably, the HSP20 family is mostly tightly repressed at low temperature, suggesting that a costly mechanism can become detrimental under unnecessary conditions. Here, the role of HSP20s in response to HS and their possible deleterious expression at non-HS temperatures is discussed.

Highlights

During summer days, mild or severe heat stress (HS) typically occurs at midday and lasts until late afternoon in terrestrial systems (Dong et al, 2017)
In most eukaryotes, including land plants, heat shock protein (HSP) accumulation depends on a signal that arises at the plasma membrane and results in the activation of heat shock transcription factor (HSF) families (Nover et al, 2001; Mishra et al, 2002; Hayashida et al, 2011; Liu et al, 2011; Scharf et al, 2012; Fragkostefanakis et al, 2015; Kijima et al, 2018)
This review has described some aspects of the heat perception and molecules involved in the signaling, triggering the accumulation of protective HSPs

Summary

Introduction

Mild or severe heat stress (HS) typically occurs at midday and lasts until late afternoon in terrestrial systems (Dong et al, 2017). In most eukaryotes, including land plants, HSP accumulation depends on a signal that arises at the plasma membrane and results in the activation of heat shock transcription factor (HSF) families (Nover et al, 2001; Mishra et al, 2002; Hayashida et al, 2011; Liu et al, 2011; Scharf et al, 2012; Fragkostefanakis et al, 2015; Kijima et al, 2018).

Results

Conclusion