Abstract It is known that Volatile Organic Compounds (VOCs), among several other mechanisms, are responsible for the antagonistic activity produced by microorganisms. In this work the volatilome of three biocontrol Bacillus velezensis strains (BUZ-14, I3 and I5) was tested in vitro and on fruit against Botrytis cinerea, Monilinia fructicola, M. laxa, Penicillium italicum, P. digitatum and P. expansum. In vitro, pathogens growth was significantly inhibited, in particular M. laxa, M. fructicola and P. italicum (66, 72 and 80 %, respectively) by BUZ-14 and B. cinerea (100 %) by I3 and I5, compared to the control. In vivo tests also showed significant inhibitions since volatile metabolites of I3 reduced grey mould in grapes by 50 % and those of BUZ-14 decreased brown rot severity in apricots, especially by M. fructicola, from 60 to 4 mm. VOCs were identified by solid phase microextraction (SPME) coupled with Gas Chromatography-Mass Spectrometry (GC–MS) and the antifungal activity of some of them was tested both in vitro and in vivo against the fungal pathogens. The main volatiles identified ranged from 12 to 15 compounds including 2-nonanone, 2-undecanone, 2-heptanone, 1-butanol, acetoin, benzaldehyde, butyl formate, diacetyl, nonane, or pyrazine, among others. Benzaldehyde and diacetyl obtained the lowest minimum inhibitory concentrations in vitro, ranging from 0.005 to 0.125 mL L−1 depending on the pathogen tested. Moreover, diacetyl was able to control grey mould caused by B. cinerea in table grapes with only 0.02 mL L−1 and to reduce blue rot in mandarins at the same dose up to 60 %. In this study, diacetyl and benzaldehyde have been identified as promising compounds to apply in active packaging during the postharvest commercialization of fruit. However, prior to the application, it is crucial to determine not only the active dose but also the phytotoxic, since some fruit species such as apples and apricots have proven to be highly sensitive.

中文翻译：

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Bacillus velezensis 菌株产生的挥发性有机化合物对采后真菌病原体的抗真菌活性

摘要 众所周知，挥发性有机化合物 (VOC) 以及其他几种机制是微生物产生拮抗活性的原因。在这项工作中，三种生物防治 Bacillus velezensis 菌株（BUZ-14、I3 和 I5）的挥发物在体外和果实上进行了测试，以对抗灰葡萄孢、念珠菌、M. laxa、意大利青霉、P. digitatum 和 P. expansum。在体外，病原体生长被 BUZ-14 显着抑制，尤其是 M. laxa、M. fructicola 和 P. italicum（分别为 66%、72% 和 80%），而 I3 和 I5 则显着抑制了 B.cinerea（100%），相比之下到控件。体内试验也显示出显着的抑制作用，因为 I3 的挥发性代谢物将葡萄中的灰霉病减少了 50%，而 BUZ-14 的那些将杏，尤其是 M. fructicola 的褐腐严重程度降低了 60 至 4 mm。通过固相微萃取 (SPME) 结合气相色谱-质谱 (GC-MS) 鉴定 VOC，并在体外和体内测试了其中一些对真菌病原体的抗真菌活性。鉴定出的主要挥发物范围为 12 到 15 种化合物，包括 2-壬酮、2-十一酮、2-庚酮、1-丁醇、乙偶姻、苯甲醛、甲酸丁酯、二乙酰、壬烷或吡嗪等。苯甲醛和双乙酰在体外获得最低的最低抑制浓度，范围从 0.005 到 0.125 mL L-1，具体取决于测试的病原体。此外，双乙酰能够以仅 0.02 mL L-1 控制鲜食葡萄中由 B. cinerea 引起的灰霉病，并在相同剂量下将橘子的蓝腐病减少高达 60%。在这项研究中，双乙酰和苯甲醛已被确定为有前途的化合物，可用于水果收获后商业化过程中的活性包装。然而，在应用之前，不仅要确定有效剂量，还要确定植物毒性，这是至关重要的，因为苹果和杏等一些水果已被证明是高度敏感的。