Requirement of functional ethylene-insensitive 2 gene for efficient resistance of Arabidopsis to infection by Botrytis cinerea

Inoculation of wild-type Arabidopsis plants with the fungus Alternaria bras sicicola results in systemic induction of genes encoding a plant defensin ( PDF1.2), a basic chitinase (PR-3), and an acidic hevein-like protein (PR-3) . Pathogen-induced induction of these three genes is almost completely abol ished in the ethylene-insensitive Arabidopsis mutant ein2-1. This indicates that a functional ethylene signal transduction component (EIN2) is require d in this response. The ein2-1 mutants were found to be markedly more susce ptible than wild-type plants to infection by two different strains of the g ray mold fungus Botrytis cinerea. In contrast, no increased fungal coloniza tion of ein2-1 mutants was observed after challenge with avirulent strains of either Peronospora parasitica or A. brassicicola. Our data support the c onclusion that ethylene-controlled responses play a role in resistance of A rabidopsis to some but not all types of pathogens.