Research Article
Characterization and Expression Analysis of Common Bean
Histone Deacetylase 6 during Development and Cold Stress
Response
Rita Kusi-Appiah Hayford,
1
Ayalew Ligaba-Osena,
2
Mayavan Subramani,
1
Adrianne
Brown,
1
Kalpalatha Melmaiee,
1,3
Khwaja Hossain,
4
and Venu (Kal) Kalavacharla
1,3
1
Molecular Genetics and EpiGenomics Laboratory, Department of Agriculture and Natural Resources, Delaware State University,
Dover, DE 19901, USA
2
Plant Biotechnology Laboratory, Department of Agriculture and Natural Resources, Delaware State University, Dover, DE 19901, USA
3
Center for Integrated Biological and Environmental Research (CIBER), Delaware State University, Dover, DE 1990, USA
4
Science and Mathematics Division, Mayville State University, Mayville, ND 58255, USA
Correspondence should be addressed to Venu (Kal) Kalavacharla; vkalavacharla@desu.edu
Received 17 June 2016; Revised 7 October 2016; Accepted 19 October 2016; Published 3 January 2017
Academic Editor: Ferenc Olasz
Copyright © 2017 Rita Kusi-Appiah Hayford et al. Tis is an open access article distributed under the Creative Commons
Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.
Histone deacetylases (HDACs) are important regulators of gene transcription thus controlling multiple cellular processes. Despite
its essential role in plants, HDA6 is yet to be validated in common bean. In this study, we show that HDA6 is involved in plant
development and stress response. Diferential expression of HDA6 was determined in various tissues and the expression was seen
to be upregulated with plant age (seedling < fowering < maturity). Higher expression was observed in fowers and pods than in stem,
leaf, and root. Upregulation of HDA6 gene during cold stress implies its prominent role in abiotic stress. Furthermore, the HDA6
gene was isolated from three common bean genotypes and sequence analyses revealed homology with functionally characterized
homologs in model species. Te 53 kDa translated product was detected using an HDA6 specifc antibody and recombinant protein
overexpressed in Escherichia coli showed HDAC activity in vitro. To our knowledge, this is the frst report in the agriculturally
important crop common bean describing the functional characterization and biological role of HDA6.
1. Introduction
In eukaryotes, epigenetic mechanisms regulate gene expres-
sion and play a signifcant role in many aspects of develop-
ment [1]. Te expression and activity of genes in eukaryotes
are not only dependent on the genome but also dependent
on the regulation conferred due to epigenetic marks such
as DNA methylation and modifcation of histones. Histones
are modifed by the process of acetylation, phosphoryla-
tion, methylation, ubiquitination, ADP-ribosylation, glycosy-
lation, or sumoylation [2] which subsequently afects interac-
tions with DNA and thus gene expression. DNA methylation,
histone modifcation, and chromatin remodeling regulate
the accessibility of DNA to transcription factors and other
regulatory proteins which afect transcriptional activities and
gene expression. Chromatin is made up of DNA and histones
as well as nonhistone proteins, which condenses DNA into
the nucleus of a cell [3]. Approximately 147 base pairs of
DNA wrap around an octamer of core histone proteins made
up of two molecules each of H2A, H2B, H3, and H4. Te
N-terminal tails of histones provide the sites for histone
modifcations [4].
Chromatin in a closed state becomes inaccessible to tran-
scription factors and other regulatory proteins. During acety-
lation, the positive charge of the lysine residues at the
amino terminal tail is removed by addition of acetyl groups
which reduces the electrostatic charge between the positively
charged histone and negatively charged DNA molecule. In an
Hindawi
International Journal of Genomics
Volume 2017, Article ID 2502691, 12 pages
https://doi.org/10.1155/2017/2502691