Bacillus species are promising agent for the biological control of postharvest diseases. This study investigated the bio-control efficiency of Bacillus halotolerans KLBC XJ-5 against grey mould caused by Botrytis cinerea in postharvest strawberries, together with its underlying antagonistic mechanism. Treatment with B. halotolerans KLBC XJ-5 controlled mycelial growth as well as conidial germination of B. cinerea in vitro. The grey mould in strawberries inoculated with B. halotolerans KLBC XJ-5 was lower in comparison with that in the control fruit after 4 d of incubation. Genome sequencing and further bioinformatic analyses suggested that strain KLBC XJ-5 harboured six antimicrobial biosynthesis gene clusters, besides four glycoside hydrolase family 18 gene clusters involved in chitin degradation. In addition, it secreted the lytic enzyme chitinase (CHI). B. halotolerans KLBC XJ-5-treated strawberries exhibited significant induced enzyme activities (polyphenol oxidase, phenylalanine ammonia lyase, β-1, 3-glucanase, and chitinase) and compounds related to disease resistance (total phenols, flavonoids). Compared to the control fruit, B. halotolerans KLBC XJ-5-treated fruit did not present differences on nutritional quality (measured in ascorbic acid, titratable acidity, and total soluble solids). Thus, it can be concluded that B. halotolerans KLBC XJ-5 could be potentially useful as a suitable bio-control agent in harvested strawberries.

芽孢杆菌种是用于收获后疾病的生物防治的有前途的试剂。这项研究调查了枯草芽孢杆菌KLBC XJ-5对灰葡萄孢在收获后草莓中引起的灰霉病的生物防治效率，以及其潜在的拮抗机理。治疗B. halotolerans KLBC XJ-5控制菌丝体生长以及分生孢子发芽灰葡萄孢在体外进行。接种了嗜盐芽孢杆菌的草莓中的灰色霉菌孵育4天后，KLBC XJ-5与对照果实相比较低。基因组测序和进一步的生物信息学分析表明，菌株KLBC XJ-5除了与几丁质降解有关的四个糖苷水解酶家族18基因簇外，还具有六个抗菌生物合成基因簇。此外，它还分泌了几丁质分解酶（CHI）。B. halotolerans KLBC XJ-5处理的草莓表现出显着的诱导酶活性（多酚氧化酶，苯丙氨酸氨裂合酶，β-1、3-葡聚糖酶和几丁质酶）和与抗病性有关的化合物（总酚，类黄酮）。与对照水果相比，嗜盐芽孢杆菌KLBC XJ-5处理的水果在营养品质上没有差异（以抗坏血酸，可滴定酸度和总可溶性固形物测量）。因此，可以得出结论，嗜盐芽孢杆菌KLBC XJ-5可以潜在地用作收获草莓中的合适生物防治剂。