A novel biocontrol strain Pantoea jilinensis D25 for effective biocontrol of tomato gray mold (causative agent Botrytis cinerea)

Botrytis cinerea is the causative agent of a common and serious disease, gray mold of tomato, which can infect the flower, fruit, leaf, and stem tissues. The occurrence of gray mold account for dramatic decrease of tomato yield, threatening the food security, with rarely effective biocontrol approach. In this study, we isolated 56 bacterial strains from tomato rhizosphere, with 7 strains among which had great control effect against B. cinerea. Among the 7 identified strains, Pantoea jilinensis D25 which had the strongest inhibitory effect, was a new strain. Further we found that P. jilinensis D25 can inhibit the mycelial growth and spore production of B. cinerea, with alterations of the mycelial morphology of B. cinerea. The highest growth inhibition (83.1%) of B. cinerea occurred upon the exposure to a concentration of 5.0×105 cfu/mL of P. jilinensis D25, at pH 6 and 25 °C. The inhibitory effect against B. cinerea by P. jilinensis D25 was further validated with inoculation assay on tomato leaf tissues and tomato seedlings. The results demonstrated that P. jilinensis D25 strain from soils of tomato growing areas is a new and effective biocontrol agent against notorious tomato gray mold disease.