Antagonistic Activity and the Mechanism of Bacillus amyloliquefaciens DH-4 Against Citrus Green Mold
Antagonistic Activity and the Mechanism of Bacillus amyloliquefaciens DH-4 Against Citrus Green Mold
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解淀粉芽孢杆菌DH-4对柑橘青霉病的拮抗活性及机制
DOI：
10.1094/phyto-01-17-0032-r
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发表时间：
2018-11-01
期刊：
影响因子：
3.2
通讯作者：
Long, Chao-an
中科院分区：
文献类型：
--
作者：
Chen, Kai;Tian, Zhonghuan;Long, Chao-an
柑橘类水果在贮藏和运输过程中通常会遭受重大损失。绿色霉是由指状青霉（Penicilliumdigitatum）引起的柑桔采后腐烂病，是柑桔上最严重的真菌病害之一。通过形态观察和16 S rDNA分析，确定拮抗菌株DH-4为解淀粉芽孢杆菌（Bacillus amyloliquefaciens）。此外，它还表现出广泛的抗真菌活性，特别是对青霉菌的抑制作用。菌株DH-4的培养滤液对指状假单胞菌具有明显的体内外抑菌活性。在贮藏过程中，添加DH-4的培养滤液具有较好的防腐效果。菌株DH-4发酵滤液中的抗真菌物质在各种极端条件下均表现出稳定的活性。此外，通过超高效液相色谱（UPLC）电喷雾电离质谱分析，在培养滤液中的抗真菌物质被确定为macrolactin，bacillaene，iturins，fengycin和surfactin。含有这些抗真菌化合物的UPLC级分基本上是耐热的，并且全部负责对指状青霉的拮抗活性。透射电镜观察表明，抗真菌物质可能引起指状青霉细胞超微结构的异常，这可能是B的作用方式。解淀粉菌对抗指状假单胞菌。此外，通过扫描电镜分析证实，其抑制指状假单胞菌的主要途径是分泌抗菌化合物，而不是直接相互作用。本研究有助于对B作用机制的理解。本研究为柑橘采后腐烂病的生物防治提供了潜在的应用前景。
Citrus fruit usually suffer significant losses during the storage and transportation stages. Green mold, a postharvest rot of citrus fruit caused by Penicillium digitatum, is one of the most serious fungal diseases. In this study, the antagonist strain DH-4 was identified as Bacillus amyloliquefaciens according to morphological observation and 16S ribosomal DNA analysis. In addition, it showed broad antifungal activity, especially the suppression of Penicillium spp. The culture filtrate of strain DH-4 exhibited apparent activity against P. digitatum in vitro and in vivo. In storage, the culture filtrate with DH-4 in it showed a better antiseptic effect. The antifungal substances in the culture filtrate, produced by strain DH-4, displayed stable activity in various extreme conditions. In addition, the antifungal substances in the culture filtrate were identified as macrolactin, bacillaene, iturins, fengycin, and surfactin by ultraperformance liquid chromatography (UPLC) electrospray ionization mass spectrometry analysis. The UPLC fractions containing these antifungal compounds were basically heat tolerant and all responsible for the antagonistic activity against P. digitatum. Transmission electron microscope observation indicated that the antifungal substances might cause abnormalities in the P. digitatum cellular ultrastructure, which could be the possible mode of action of B. amyloliquefaciens against P. digitatum. In addition, it was confirmed via scanning electron microscope analysis that the main way it inhibited P. digitatum was by secreting antimicrobial compounds without direct interaction. This study contributes to the understanding of the mechanism of B. amyloliquefaciens against citrus green mold as well as providing a potential application for the biocontrol of postharvest rot diseases in citrus fruit.