The acetylation level of histones on lysine residues regulated by histone acetyltransferases and histone deacetylases plays an important but under-studied role in the control of gene expression in plants. With the aim of characterizing the Arabidopsis RPD3/HDA1 family histone deacetylase HDA5, we present evidence showing that HDA5 displays deacetylase activity. Mutants defective in the expression of HDA5 displayed a late-flowering phenotype. Expression of the flowering repressor genes FLC and MAF1 was up-regulated in hda5 mutants. Furthermore, the gene activation markers, histone H3 acetylation and H3K4 trimethylation on FLC and MAF1 chromatin were increased in hda5-1 mutants. Chromatin immunoprecipitation analysis showed that HDA5 binds to the chromatin of FLC and MAF1. Bimolecular fluorescence complementation assays and co-immunoprecipitation assays showed that HDA5 interacts with FVE, FLD and HDA6, indicating that these proteins are present in a protein complex involved in the regulation of flowering time. Comparing gene expression profiles of hda5 and hda6 mutants by RNA-seq revealed that HDA5 and HDA6 co-regulate gene expression in multiple development processes and pathways.
Keywords: Arabidopsis; HDA5; HDA6; flowering; histone deacetylase.
© 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.