Identification of Streptomyces anandii FXJ-25 and Its Control Efficacy Against Tobacco Target Spot Pathogen

In order to screen the antagonism of tobacco target spot pathogen and provide a new biocontrol resource for the control of tobacco target spot, strain FXJ-25 with obvious antagonistic effects was obtained by dilution plating and plate confrontation methods. This strain was identified based on the combination of culture characteristics, physiological and biochemical characteristics and 16S rDNA gene sequence analysis. The ability of strain FXJ-25 to induce tobacco resistance was analyzed, and its control effect was studied by pot control experiment. The results showed that a strain of FXJ-25 identified as Streptomyces anandii was obtained, which had an inhibitory rate of 74.14% against the pathogen of tobacco target spot and could cause mycelial malformation. FXJ-25 has broad-spectrum antifungal activities, possessing inhibitory rates of 53.43% to 100% to 15 plant pathogenic fungi including Stagonosporopsis cucurbitacearum, Colletotrichum karstii and Fusarium graminearum. The fermentation broth of this strain could also significantly induce and increase the activities of defense-related enzymes such as phenylalanine ammonia-lyase (PAL), peroxidase (POD), polyphenol oxidase (PPO), catalase (CAT) and so on. In the pot control experiment, the live bacterial solution （10⁸ spores/mL）of strain FXJ-25 had 78.81% control efficiency on tobacco target spot. Therefore, FXJ-25 can be used as a biocontrol resource for tobacco target spot disease control for further development and utilization.