AtHD2D Gene Plays a Role in Plant Growth, Development, and Response to Abiotic Stresses in Arabidopsis thaliana

Abstract

The histone deacetylases play important roles in the regulation of gene expression and the subsequent control of a number of important biological processes, including those involved in the response to environmental stress. A specific group of histone deacetylase genes, HD2, is present in plants. In Arabidopsis, HD2s include HD2A, HD2B, HD2C, and HD2D. Previous research showed that HD2A, HD2B, and HD2C are more related in terms of expression and function, but not HD2D. In this report, we studied different aspects of AtHD2D in Arabidopsis with respect to plant response to drought and other abiotic stresses. Bioinformatics analysis indicates that HD2D is distantly related to other HD2 genes. Transient expression in Nicotiana benthamiana and stable expression in Arabidopsis of AtHD2D fused with gfp showed that AtHD2D was expressed in the nucleus. Overexpression of AtHD2D resulted in developmental changes including fewer main roots, more lateral roots, and a higher root:shoot ratio. Seed germination and plant flowering time were delayed in transgenic plants expressing AtHD2D, but these plants exhibited higher degrees of tolerance to abiotic stresses, including drought, salt, and cold stresses. Physiological studies indicated that the malondialdehyde (MDA) content was high in wild-type plants but in plants overexpressing HD2D the MDA level increased slowly in response to stress conditions of drought, cold, and salt stress. Furthermore, electrolyte leakage in leaf cells of wild type plants increased but remained stable in transgenic plants. Our results indicate that AtHD2D is unique among HD2 genes and it plays a role in plant growth and development regulation and these changes can modulate plant stress responses.

Canonical and Noncanonical Actions of Arabidopsis Histone Deacetylases in Ribosomal RNA Processing

“…Loss-of-function HD2C is hypersensitive to salt stress (Luo et al, 2012) and plants overexpressing HD2C confer resistance to ABA and drought treatments (Sridha and Wu, 2006). Overexpression of HD2D enhances salt and cold tolerance (Han et al, 2016). We observed upregulation of many ribosome biogenesis genes and downregulation of many stress response genes in hd2b hd2c (Supplemental Data Set 4).…”

“…It is possible that HD2 proteins may have evolved to play important roles in the environmental adaption. Genetic studies showed that HD2 proteins are involved in various stress responses (Luo et al, 2012;Buszewicz et al, 2016;Han et al, 2016). Loss-of-function HD2C is hypersensitive to salt stress (Luo et al, 2012) and plants overexpressing HD2C confer resistance to ABA and drought treatments (Sridha and Wu, 2006).…”

Epigenetic regulation in plant abiotic stress responses

“…Overexpression of Arabidopsis Histone Deacetylase 2D (HD2D) resulted in a slow increase in malondialdehyde (MDA) content upon cold stress treatment. As a result, the transgenic plants were more tolerant to cold treatment (Han et al 2016). It has been shown that histone acetylation is induced upon cold treatment in the promoter regions of some COR genes, such as COR15A and COR47 (Pavangadkar et al 2010).…”

Diurnal changes in concerted plant protein phosphorylation and acetylation in Arabidopsis organs and seedlings

“…Similar to kinases and phosphatases involved in protein phosphorylation, protein acetylation is catalyzed by two families: the lysine acetyltransferases (KATs) and the lysine deacetylases (KDACs), which catalyze the addition and removal of acetyl groups from target proteins, respectively (Pandey et al, 2002;Tran et al, 2012b;Uhrig et al, 2017). Both protein phosphorylation and acetylation have been shown to regulate key cellular processes, such as glycolysis, nitrogen metabolism, photosynthesis (Finkemeier et al, 2011;Engelsberger and Schulze, 2012;Menz et al, 2016) and development (Han et al, 2016;Zhao et al, 2017). To date, protein phosphorylation and acetylation have each been characterized separately in plants, even though they may work synergistically or antagonistically to impact function when occuring on the same protein (Soufi et al, 2012;Tran et al, 2012a;Mertins et al, 2013;Rao et al, 2014;Sharma et al, 2014).…”