Screening of endophytic bacteria antagonistic against Ustilaginoidea virens in rice

Abstract

Rice false smut (RFS) caused by Ustilaginoidea virens is a major disease in rice-producing areas in China. Endophytic bacteria have prominent advantages in controlling host plant diseases. To screen and obtain the antagonistic bacteria of RFS and effectively control RFS, the antagonistic strains were screened from 45 rice endophytic bacteria by the method of plate pair culture, the antagonistic activity of the fermentation broth of the antagonistic strains was measured, and the RFS field control test was performed. The results showed that 45 strains of rice endophytic bacteria had antagonistic activity against on U. virens, of which 23 strains had an antagonistic band of more than 15 mm. The fermented broth of these 23 antagonistic strains had strong antagonistic activity against on U. virens, of which 17 strains had antagonistic band of more than 20 mm, and 3 of them (REB01, REB32, and REB42) had more than 28 mm. . The three strains (REB01, REB32 and REB42) had 81.48%, 72.05% and 76.76% of respectively field control effect on RFS, which was very significant (P <0.01) higher than the field control effect of 500-fold dilution of 5% Jinggangmycin (61.72%), and showing great potential for biological control of RFS.