Inhibitory effect of L-Methionine on bacterial speck of tomato

Abstract

L-methionine (L-Met) is an amino acid necessary for protein biosynthesis. In this study, the inhibitory effect of L-Met on bacterial speck of tomato (Pseudomonas syringae pv. tomato: PST) was investigated. When leaves of tomato plants pretreated with L-Met were inoculated with PST, symptoms were reduced compared with the control. In addition, we measured the number of bacteria in the inoculated leaves. Decreased bacterial growth was observed in the inoculated leaves of L-Met-treated plants. Furthermore, we investigated the expression of PR1b reported as a marker gene in the SA signaling pathway in L-Met-treated plants after PST inoculation. Enhancement of the gene expression was observed in L-Met-treated plants after inoculation. These observations suggested that the inhibitory effect of L-Met treatment on bacterial speck of tomato may be due to priming the SA-related signaling pathway.