Antifungal activity screening of soil actinobacteria isolated from Inner Mongolia, China

Screening for novel biocontrol agents against plant pathogens is highly desired to prevent and control a wide variety of plant diseases. In this study, a total of 183 actinobacteria were screened for their antifungal activities both in vitro and in vivo. Among these, three isolates (12-09-4, 12-09-11 and 12-08-14) exhibited potent antifungal activity against Botrytis cinerea and Fusarium oxysporum f. sp. cucumerinum, and therefore chosen for secondary screening. Notably, 12-09-4 and 12-09-11 strains showed broad-spectrum antifungal activity against all the tested pathogens, and the inhibition rates of spore germination on F. oxysporum f. sp. cucumerinum were 95.38% and 96.14%, respectively. Moreover, the two strains showed strong protective effects (>70%) on wheat powdery mildew. Based on the 16S rDNA analysis, the two strains were identified as for genus Streptomyces. In conclusion, Streptomyces 12-09-4 and 12-09-11 might have potential to be developed as biocontrol agents against wheat powdery mildew and hoping to step towards sustainable agriculture.