Isolation and Characterization of an Arabidopsis ABA Hypersensitive Mutant ahg3

Abstract

We isolated Arabidopsis mutants that have an altered ABA sensitivity using ABA analog. One of these putative ABA hypersensitive mutants, ahg3 (ABA hypersensitive germination 3) is analyzed in this study. This mutant exhibit less germination or growth activities at the presence of ABA analog as well as ABA. Characterization of ahg3 revealed that ahg3 have enhanced sensitivity to salinity and high osmotic stress. Northern blot analysis revealed that ahg3 shows delayed induction of ABA inducible genes. We conducted mapping of ahg3 and identified a point mutation in the AtPP2CA gene that encodes a protein phosphatase 2C (PP2C) protein. PP2C is predicted to be a negative regulator of ABA pathway. We want to prove this prediction through the identification of ahg3 loci and analysis of AHG3 protein.