The Arabidopsis WDR55 is positively involved in ABA-mediated drought tolerance response

Abstract

WD40 repeat-containing protein 55 (WDR55) is one of the damaged DNA-binding WD40 (DWD) proteins in Arabidopsis, which is known to be involved in plant development of the reproductive and vegetative stages. In this study, we found that WDR55 was induced in plants treated with the phytohormone abscisic acid (ABA) or abiotic stresses, such as drought. Transgenic Arabidopsis plants that overexpress WDR55 showed ABA-hypersensitive phenotypes and tolerance to drought, whilst the wdr55 mutant showed the opposite results. In addition, transcriptome analysis showed that the transcript levels of ABA- and drought-responsive genes were increased in WDR55-overexpresing plants. Furthermore, some ABA-responsive genes, such as RD29B, were regulated through the histone modifications in its promoter region in a WDR55-dependent manner. Taken together, these results suggest that WDR55 plays as a positive regulator in ABA-mediated drought stress response in Arabidopsis.