Could be involved in facilitating the biotrophic relationship between the plant and the rust fungus. an aldehyde + H2O + NAD(+) = a carboxylate + 2 H(+) + NADH In uninfected plants, highest levels found in stems. In plants infected with the flax rust, highest levels in leaves. Higher levels of expression in infected leaves than uninfected stems. By flax rust susceptible infection but not by resistant infection. Levels 10-fold higher in infected plants than uninfected plants. Belongs to the aldehyde dehydrogenase family.