AUTHOR=Han Zhaofen , Yu Huimin , Zhao Zhong , Hunter David , Luo Xinjuan , Duan Jun , Tian Lining 

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

JOURNAL=Frontiers in Plant Science

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.00310

DOI=10.3389/fpls.2016.00310

ISSN=1664-462X

ABSTRACT=<p>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, <italic>HD2</italic>, is present in plants. In <italic>Arabidopsis, HD2s</italic> include <italic>HD2A, HD</italic>2<italic>B, HD</italic>2<italic>C</italic>, and <italic>HD</italic>2<italic>D</italic>. Previous research showed that <italic>HD2A, HD2B</italic>, and <italic>HD2C</italic> are more related in terms of expression and function, but not <italic>HD2D.</italic> In this report, we studied different aspects of <italic>AtHD2D</italic> in <italic>Arabidopsis</italic> with respect to plant response to drought and other abiotic stresses. Bioinformatics analysis indicates that <italic>HD2D</italic> is distantly related to other <italic>HD2</italic> genes. Transient expression in <italic>Nicotiana benthamiana</italic> and stable expression in <italic>Arabidopsis</italic> of <italic>AtHD2D</italic> fused with <italic>gfp</italic> showed that <italic>AtHD2D</italic> was expressed in the nucleus. Overexpression of <italic>AtHD2D</italic> 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 <italic>AtHD2D</italic>, 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 <italic>HD2D</italic> 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 <italic>AtHD2D</italic> is unique among <italic>HD2</italic> genes and it plays a role in plant growth and development regulation and these changes can modulate plant stress responses.</p>