海洋生境贝莱斯芽孢杆菌TCS001的鉴定及抑真菌活性

为研究海洋生境芽孢杆菌TCS001的分类地位和抑菌活性，通过形态和生理生化特征观察，并结合gyrA序列同源性分析对菌株进行了鉴定；通过平板对峙培养法测定了菌株TCS001对多种植物病原真菌的抑菌谱；采用菌丝生长速率法和凹玻片法，测定了不同浓度TCS001菌株发酵滤液对靶标菌黄瓜灰霉病菌Botrytis cinerea菌丝生长和孢子萌发的影响。结果显示:该菌株为贝莱斯芽孢杆菌Bacillus velezensis，其对6种供试病原菌均有一定的抑制效果，其中对黄瓜灰霉病菌的抑制率最高，达87.66%。不同稀释倍数下，TCS001发酵滤液对黄瓜灰霉病菌均有一定的抑制作用，其中，稀释5倍时对菌丝生长和孢子萌发的抑制率最高，分别为96.24%和98.05%，稀释20倍时抑制率也均达90%以上。形态学观察发现，TCS001发酵滤液可导致黄瓜灰霉病菌孢子萌发芽管中间或顶端膨大畸形。研究表明，海洋生境贝莱斯芽孢杆菌TCS001极具开发为微生物农药的潜能。

Identification and antifungal activity of marine Bacillus velezensis strain TCS001

To study the taxonomic category and antifungal activity of the marine Bacillus sp. strain TCS001, the strain TCS001 as Bacillus velezensis based on the morphological, physiological and biochemical characteristics as well as analyzation of the sequence of gyrA was identified. The antifungal spectrum of strain TCS001 was determined by the dural culture method. The effects of strain TCS001 fermentation filtrate on the mycelial growth and spore germination of the target fungus, Botrytis cinerea, were also investigated using the mycelial growth rate method and the concave slide method. The results showed that the strain TCS001 had obvious antifungal activity against six pathogenic fungi, especially B. cinerea, the inhibition rates of which was 87.66%. Several different dilutions of fermentation filtrate exhibted significant inhibition efficacy against B. cinerea mycelial growth and spore germination. Five times diluted fermentation filtrate generated the highest mycelial growth and spore germination inhibition rates of 96.24% and 98.05%, respectively. The inhibition efficacy against mycelial growth and spore germination was still over 90% when the fermentation filtrate was diluted by 20 folds. Strain TCS001 fermentation filtrate could alter B. cinerea spore germination, such as expansion and deformation, according to the morphological observation. This study provided a solid evidence that B. velezensis strain TCS001 is a very promising bioagent for controlling plant fungal diseases.