Abstract:

Cotton Verticillium wilt, which is caused by Verticillium dahliae kleb is a worldwide disastrous plant vascular disease. Bacteria strain 12-51 with a rather higher antagonistic activity was obtained after primary and secondary screening. The morphology characteristics, physiological and biochemical properties and 16S rDNA sequence of this strain were studied. The similarity of the 16S rDNA sequences between bacteria strain 12-51 and Bacillus velezensis were up to 99.74%. So, the strain 12-51 was finally identified as Bacillus velezensis. It was determined preliminarily that the extracts were proteins by analyzing the antifungal activity of the extracted substance through organic solvent extraction and salting-out method against Verticillium dahliae Kleb. The results showed that the component of 60% extracted substance had the biggest inhibition zone and the antifungal protein was not sensitive to the heat and pH value. The results laid the foundation for the biological control of Cotton Verticillium wilt.