The Histone-Modifying Complex PWR/HOS15/HD2C Epigenetically Regulates Cold Tolerance.

Chae Jin Lim,Sang Yeol Lee,Ki Suk Park,Byeong-Ha Lee,Masood Jan,Min Jae Bae,Mi Sun Cheong,Junghoon Park,Jose M Pardo,Dongwon Baek,Mingzhe Shen,Woe-Yeon Kim,Ahktar Ali,Dea-Jin Yun,Hee Jin Park

doi:10.1104/pp.20.00439

Abstract

Cold stress is a major environmental stress that severely affects plant growth and crop productivity. Arabidopsis (Arabidopsis thaliana) HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE15 (HOS15) is a substrate receptor of the CULLIN4-based CLR4 ubiquitin E3 ligase complex, which epigenetically regulates cold tolerance by degrading HISTONE DEACETYLASE2C (HD2C) to switch from repressive to permissive chromatin structure in response to cold stress. In this study, we characterized a HOS15-binding protein, POWERDRESS (PWR), and analyzed its function in the cold stress response. PWR loss-of-function plants (pwr) showed lower expression of cold-regulated (COR) genes and sensitivity to freezing. PWR interacts with HD2C through HOS15, and cold-induced HD2C degradation by HOS15 is diminished in the pwr mutant. The association of HOS15 and HD2C to promoters of cold-responsive COR genes was dependent on PWR. Consistent with these observations, the high acetylation levels of histone H3 by cold-induced and HOS15-mediated HD2C degradation were significantly reduced in pwr under cold stress. PWR also interacts with C-repeat element-binding factor transcription factors to modulate their cold-induced binding to the promoter of COR genes. Collectively, our data signify that the PWR-HOS15-HD2C histone-modifying complex regulates the expression of COR genes and the freezing tolerance of plants.

Highlights

Cold stress is one of the major environmental factors that seriously limit the growth and productivity of plants
PWR is a homolog of the repressor complex protein NCoR1 of mammals that in Arabidopsis interacts with HOS15 (Park et al, 2018b; Suzuki et al, 2018; Mayer et al 2019)
We examined whether the expression levels of the C-repeat element-binding factor (CBF) transcription factors that regulate the expression of cold-responsive genes through direct binding to the promoter regions of COR genes (Chinnusamy et al, 2007) were altered in the pwr mutants

Summary

Introduction

Cold stress is one of the major environmental factors that seriously limit the growth and productivity of plants. To overcome this constraint, plants have developed effective ways to increase resistance to cold stress and freezing. Cold acclimation is a process that increases freezing tolerance upon exposure to low but non-freezing temperatures. This process involves the activation or expression of cold-regulated (COR) genes, and consequent physiological and biochemical changes in response to cold stress (Guo et al, 2018; Ding et al, 2019). One of the best-characterized mechanisms is the C-repeat element-Binding

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Conclusion