Aldehyde reductase that catalyzes the reduction of the aldehyde carbonyl groups on saturated and alpha,beta-unsaturated aldehydes with more than 5 carbons (PubMed:21169366). Involved in basal resistance against pathogens. (+)-neomenthol + NADP(+) = (1R,4S)-menthone + H(+) + NADPH kcat is 0.27 sec(-1) for (E)-2-pentenal. kcat is 0.4 sec(-1) for (E)-2-hexenal. Optimum pH is 9.0 for the forward reaction and 8.0 for the reverse reaction. Monomer. A number of isoforms are produced. According to EST sequences. By pathogen infection. Not detected in healthy leaves. Belongs to the short-chain dehydrogenases/reductases (SDR) family.