Induction of resistance in tomato by β-aminobutyric acid against Clavibacter michiganensis subsp. michiganensis Ta18 strain isolated from Iran

Bacterial canker caused by Clavibacter michiganensis subsp. michiganensis is an economically important disease of tomato. In this study after isolation and characterization of the pathogen, effects of tomato pre-treatment with DL-β-aminobutyric acid (BABA) on bacterial canker was investigated under laboratory conditions. BABA is known as a powerful chemical resistance inducer in plants against diverse pathogens. In this study, tomato plants were treated with a 0.2 mM concentration of BABA and distilled water served as control. The plants were subsequently challenged with a 1×108 CFU ml−1 bacterial suspension. The results of experiments in different time intervals showed that BABA pre-treatment resulted in a significant reduction of bacterial population and symptoms severity of inoculated plants as compared to their controls. Furthermore, late appearance of disease symptoms indicated longer incubation periods for BABA treated plants. Also, a significant increase was observed in the expression of PR1 and catalase genes in treated plants. Based on our results and regarding the lack of proper management options against the disease, application of BABA as an environmentally safe agent is recommended as a valuable contribution to disease management.