Bacillus subtilis KLBC BS6 induces resistance and defence-related response against Botrytis cinerea in blueberry fruit

Abstract

The potential biocontrol strain Bacillus subtilis KLBC BS6 was isolated from blueberry rhizosphere soil, and its efficacy for controlling grey mould caused by Botrytis cinerea in postharvest blueberry fruit and the underlying possible disease resistance mechanisms were investigated. Treatment with B. subtilis KLBC BS6 was expected to inhibit the mycelial growth and conidial germination of B.cinerea in vitro. The incidence of grey mould in blueberry fruit treated with B. subtilis KLBC BS6 (and inoculated with B. cinerea) was decreased compared with that in the control fruit after 4 days of incubation, regardless of the preventive or curative nature of the treatment. Moreover, preventive treatment was more effective than the curative one in controlling of grey mould-induced decay. In B. subtilis KLBC BS6-treated blueberry fruit, the activities of disease resistance-related enzymes (chitinase, phenylalanine ammonia lyase, peroxidase, and polyphenol oxidase) were significantly enhanced. Furthermore, compared to the control fruit, the B. subtilis KLBC BS6-treated blueberry fruit exhibited unimpaired internal fruit quality and maintained high titratable acidity and ascorbic acid content. Thus, B. subtilis KLBC BS6 is a suitable biocontrol agent for prolonging the postharvest shelf-life of blueberry fruit and other horticultural products.