ThePlantCell,Vol.253491–3505.PDF

The Plant Cell, Vol. 25: 3491–3505, September 2013, ã 2013 American Society of Plant Biologists. All rights reserved. Histone Deacetylase Complex1 Expression Level Titrates Plant Growth and Abscisic Acid Sensitivity in Arabidopsis C W OPEN Giorgio Perrella,a Manuel A. Lopez-Vernaza,a,1 Craig Carr,a Emanuela Sani,a,1 Veronique Gosselé,b Christoph Verduyn,b Fabian Kellermeier,a Matthew A. Hannah,b and Anna Amtmanna,2 a Plant Science Group, Institute of Molecular, Cell, and Systems Biology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow G128QQ, United Kingdom b Bayer CropScience, B-9052 Ghent, Belgium Histone deacetylation regulates gene expression during plant stress responses and is therefore an interesting target for epigenetic manipulation of stress sensitivity in plants. Unfortunately, overexpression of the core enzymes (histone deacetylases [HDACs]) has either been ineffective or has caused pleiotropic morphological abnormalities. In yeast and mammals, HDACs operate within multiprotein complexes. Searching for putative components of plant HDAC complexes, we identified a gene with partial homology to a functionally uncharacterized member of the yeast complex, which we called Histone Deacetylation Complex1 (HDC1). HDC1 is encoded by a single-copy gene in the genomes of model plants and crops and therefore presents an attractive target for biotechnology. Here, we present a functional characterization of HDC1 in Arabidopsis thaliana . We show that HDC1 is a ubiquitously expressed nuclear protein that interacts with at least two deacetylases (HDA6 and HDA19), promotes histone deacetylation, and attenuates derepression of genes under water stress. The fast-growing HDC1-overexpressing plants outperformed wild-type plants not only on well-watered soil but also when water supply was reduced. Our findings identify HDC1 as a rate-limiting component of the histone deacetylation machinery an