Isolation and characterization of methyl jasmonate‐inducible genes in chinese cabbage

Methyl jasmonate (MeJA) is a signal molecule in the activation of defense responses in plants. In this study, we isolated 15 MeJA‐inducible genes by subtractive hybridization. These genes encode two myrosinase‐binding proteins, five lipase‐like proteins, a polygalacturonase inhibitor, a putative chlorophyll‐associated protein, a terpene synthase, a dehydroascorbate reductase, an ascorbate oxidase, a cysteine protease, an O‐methyltransferase, and an epithiospecifier protein. Northern analysis showed that most of the Chinese cabbage genes are barely expressed in healthy leaves, but are strongly induced by MeJA treatment. We also examined whether these MeJA‐inducible genes were activated by ethethon, BTH, and Pseudomonas syringae pv. tomato (Pst), a nonhost pathogen of Chinese cabbage. The results showed that none of the MeJA‐inducible genes was strongly induced by ethephon or by BTH. The genes encoding lipase‐like proteins and a myrosinase‐binding protein were weakly induced by Pst. Other MeJA‐inducible genes were not activated at all by the pathogen.