Identificationandantifungalactivityofmarine<italic>Bacillusvelezensis</italic>strainTCS001

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.