In an attempt to develop a biological control agent against mycotoxigenic Fusarium species, we isolated Bacillus amyloliquefaciens strain DA12 from soil and explored its antimicrobial activities. DA12 was active against the growth of mycotoxigenic F. asiaticum, F. graminearum, F. proliferatum, and F. verticillioides both in vitro and in planta (maize). Further screening using dual culture extended the activity range of strain DA12 against other fungal pathogens including Botrytis cinerea, Colletotrichum coccodes, Endothia parasitica, Fusarium oxysporum, Raffaelea quercus-mongolicae, and Rhizoctonia solani. The butanol extract of the culture filtrate of B. amyloliquefaciens DA12 highly inhibited the germination of F. graminearum macroconidia with inhibition rate 83% at a concentration of 31.3 μg/ml and 100% at a concentration of 250 μg/ml. The antifungal metabolite from the butanol extract was identified as iturin A by thin layer chromatography-bioautography. In addition, volatile organic compounds produced by DA12 were able to inhibit mycelial growth of various phytopathogenic fungi. The volatile compounds were identified as 2-heptanone, 5-methyl heptanone and 6-methyl heptanone by gas chromatography-mass spectrometry (GC-MS) analysis. These results indicate that the antagonistic activity of Bacillus amyloliquefaciens DA12 was attributable to iturin A and volatile heptanones, and the strain could be used as a biocontrol agent to reduce the development of Fusarium diseases and mycotoxin contamination of crops.

中文翻译：

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淀粉芽孢杆菌DA12的表征显示出对霉菌毒素镰刀菌属物种的有效抗真菌活性。

为了开发针对霉菌镰刀菌属物种的生物防治剂，我们从土壤中分离了解淀粉芽孢杆菌DA12菌株，并探讨了其抗菌活性。DA12反对mycotoxigenic的生长活性F.黄龙病，禾谷镰刀菌，F. proliferatum，和F.轮枝都在体外和在植物（玉米）。双重培养进一步筛选扩大了DA12菌株对其他真菌病原体的活性范围，包括灰葡萄孢菌，炭疽菌，寄生内皮菌，尖孢镰刀菌（Fusarium oxysporum），桔梗栎（Raffaelea quercus-mongolicae）和茄根枯萎病菌（Rhizotononia solani）。解淀粉芽孢杆菌DA12培养滤液的丁醇提取物高度抑制禾本科镰刀菌的萌发在31.3μg/ ml的浓度下抑制率达83％，在250μg/ ml的浓度下抑制率达100％。来自丁醇提取物的抗真菌代谢物通过薄层色谱-生物自显影术鉴定为伊图林A。此外，DA12产生的挥发性有机化合物能够抑制各种植物致病真菌的菌丝体生长。通过气相色谱-质谱（GC-MS）分析将挥发性化合物鉴定为2-庚酮，5-甲基庚酮和6-甲基庚酮。这些结果表明，解淀粉芽孢杆菌DA12的拮抗活性可归因于伊图林A和挥发性庚酮，该菌株可作为生物防治剂减少镰刀菌的发生。 作物的疾病和霉菌毒素污染。