Application of bacterial volatiles in the pepper roots primes systemic resistance under field condition

Abstract: Bacillus amyloliquefaciens strain IN937a, which was previously known as thriving inside plant tissues and referred to as an endophyte, was reported to stimulate plant growth and induce systemic resistance (ISR) via its emission of volatile organic compounds (VOC). We investigated the ISR capacity of the VOCs collected from the strain IN937a against bacterial spot disease caused by Xanthomonas axonopodis pv. vesicatoria on pepper in the greenhouse. Among 18 bacterial VOCs, 3-pentanol was selected for further experiments. 3-pentanol was drenched onto four week-old peppers before transplanting in the field. Disease severity was assessed at seven days after pathogen challenge when infiltrated in the pepper leaves at 10, 20, 30 and 40 days post transplant (dpt). 3-pentanol treatment significantly increased ISR compared to control treatment at 30 dpt. Taken together; bacterial VOC 3-pentanol can be utilized as a trigger of ISR against a broad spectrum of pathogens under field conditions.