Induction of plant defence compounds by Pseudomonas chlororaphis PA23 and Bacillus subtilis BSCBE4 in controlling damping-off of hot pepper caused by Pythium aphanidermatum

Abstract

Bacillus subtilis strain BSCBE4 and Pseudomonas chlororaphis strain PA23 (=P. aureofaciens) were effective biocontrol agents against Pythium aphanidermatum, the causal agent of damping-off of hot pepper (Capsicum annum L.) in greenhouse vegetable production systems. Application of strains BSCBE4 and PA23 at the rate of 20 g kg⁻¹ of seed significantly increased the growth of hot pepper seedlings. The efficacies of various carriers in sustaining the population of these strains in storage were assessed. Both the antagonists survived up to 180 days of storage in peat and talc-based formulations. The two bacterial strains induced development of plant defence-related enzymes including phenylalanine ammonia lyase, peroxidase, polyphenol oxidase, phenol content, suppressed incidence of damping-off and increased growth of hot pepper seedlings.

Keywords:

• Damping-off
• Pythium aphanidermatum
• hot pepper
• induced resistance
• Pseudomonas
• Bacillus

Acknowledgments

We acknowledge Drs Jeannie Gilbert (Cereal Research Centre, Agriculture and Agri-Food Canada, Winnipeg, MB, Canada R3T 2M9) and Mathieu Dusabenyagyasani, University of Manitoba for their valuable comments in improving the manuscript. We thank NSERC for partially funding this project.