Abstract
We isolated a novel ABA hypersensitive mutant named ahg12 (ABA hypersensitive germination 12) in Arabidopsis. Using a map-based cloning, we identified a missense mutation in the gene encoding a subunit of 26S proteasome. The ahg12 mutant also showed some pleiotropic phenotypes other than ABA hypersensitivity. The combination of phenotypes observed in ahg12 is distinct from those of other subunit mutants reported so far, suggesting that the ahg12 mutation affects the selectivity of protein degradation depending on the subunit. The ahg12 mutation, which is an unreported dominant mutation, is expected to provide new information about the functions of the subunit in the protein degradation and ABA response. Furthermore, since the 26S proteasome is highly conserved among eukaryotes, the findings from this study can be applied to other species. Detailed analyses of this mutation in plant and yeast are now ongoing.
