Plant Responses to Heat Stress: Physiology, Transcription, Noncoding RNAs, and Epigenetics

Abstract

Global warming has increased the frequency of extreme high temperature events. High temperature is a major abiotic stress that limits the growth and production of plants. Therefore, the plant response to heat stress (HS) has been a focus of research. However, the plant response to HS involves complex physiological traits and molecular or gene networks that are not fully understood. Here, we review recent progress in the physiological (photosynthesis, cell membrane thermostability, oxidative damage, and others), transcriptional, and post-transcriptional (noncoding RNAs) regulation of the plant response to HS. We also summarize advances in understanding of the epigenetic regulation (DNA methylation, histone modification, and chromatin remodeling) and epigenetic memory underlying plant–heat interactions. Finally, we discuss the challenges and opportunities of future research in the plant response to HS.

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

“…The expression of HSPs in plants is regulated by epigenetics, such as DNA methylation, histone modification, and chromatin remodeling ( Boyko et al, 2010 ; Gao et al, 2014 ; Gallego-Bartolomé, 2020 ; Zhao et al, 2021 ). HSPs gene must be unwrapped from histones to become actively transcribed when HSF1As are bound to HSEs ( Figure 1 ).…”

“…Histone chemical modifications, such as methylation and acetylation, have been also indicated to be important for the regulation of HSPs in plants ( Lämke et al, 2016 ; Yamaguchi et al, 2021 ). Regarding non-coding RNA (ncRNA), such as microRNAs (miRNAs) and small interfering RNAs (siRNAs), its involvement in the regulation of the HSR has been suggested in several land plant species ( Khraiwesh et al, 2012 ; Li et al, 2014 ; Zhao et al, 2016 ; Liu et al, 2017 ; Lin J. S. et al, 2018 ; Zhao et al, 2021 ). Thus, following a short period of HS, epigenetic processes have also been implicated in developing a transcriptional heat memory ( Bäurle and Trindade, 2020 ).…”

“…Acquired thermotolerance (AT) refers to the plant adaptive capacity to survive noxious HS when exposed to sublethal temperatures, requiring the accumulation of HSPs. Under HS, both transcriptome and proteome-based studies have indicated regulatory responses of HSPs ( Qin et al, 2008 ; Finka et al, 2011 ; Mangelsen et al, 2011 ; Xin et al, 2016 ; Guihur et al, 2020 ; Zhao et al, 2021 ). A conserved subfamily called “heat-induced molecular chaperones” contains the HSP100s, HSP90s, HSP70s, HSP60s, HSP40s, and HSP20s ( Al-Whaibi, 2011 ; Jee, 2016 ).…”

“…Following the activation of CNGCs, and a still unclear signaling pathway, HSFA1 is translocated into the nucleus and can bind specific DNA motifs present in the promoter of HSP genes, called “heat shock element” (HSE) ( Santoro et al, 1998 ; Liu and Charng, 2012 ). HSFA1 could also trigger regulatory responses, including DNA methylation, histone modification, and chromatin remodeling ( Zhao et al, 2021 ). In particular, bound histones to HSP genes, such as H2A.Z, must be evicted to allow for RNA polymerase II docking for the transcription of HSP ( Franklin, 2010 ; Kumar and Wigge, 2010 ; Probst and Mittelsten Scheid, 2015 ).…”

Epigenetics: A Key to Comprehending Biotic and Abiotic Stress Tolerance in Family Poaceae

“…Plants exposed to high temperature (heat stress, HS), significant abiotic stress due to increased global warming, suffer from severe, and sometimes lethal, adverse effects. Plants have evolved complex mechanisms to respond to this kind of stress in order to cope with such conditions [132]. Another study on rice and heat stress found that OsFIE1 facilitated seed size reduction (fertilization-independent endosperm).…”