Expression of PR-protein genes and induction of defense-related enzymes by Bacillus subtilis CBR05 in tomato (Solanum lycopersicum) plants challenged with Erwinia carotovora subsp. carotovora.

The present study was aimed to evaluate the effectiveness of a biocontrol agent Bacillus subtilis CBR05 for control of soft rot disease (Erwinia carotovora subsp. carotovora) in tomato, and the possible mechanisms of its resistance induction have been investigated under pot conditions. Results showed that plants inoculated with B. subtilis CBR05 had lower disease incidence (36%). A significant increase in superoxide dismutase, catalase, peroxidase, and polyphenol oxidase activities was observed in plants inoculated with B. subtilis between 48 and 72 hpi. Also, the transcript profiles of Glu and Phenyl ammonia lyase (PAL) showed a significant up-regulation following inoculation. The most significant up-regulation was observed in transcript profile of PAL that showed 0.49 Fold Expression, at 72 hpi as compared to its expression at 12 hpi. These results suggest that systemic induction of defense-related genes expression and antioxidant enzyme activity by B. subtilis could play a pivotal role in disease resistance against soft rot disease.