Suppression of Rice Blast by Bacterial Strains Isolated from Cultivated Soda Saline-Sodic Soils

• Main Authors: Yi Wei, Lanhui Li, Wenjun Hu, Huiyan Ju, Mingzhe Zhang, Qingming Qin, Shihong Zhang, Guihua Li
• Format: Article
• Language: English
• Published: MDPI AG 2020-07-01
• Series: International Journal of Environmental Research and Public Health
• Subjects: <i>Magnaporthe oryzae</i>; rice blast disease; biological control; saline-sodic land; soil bacteria; antagonistic bacterial strain
• Online Access: https://www.mdpi.com/1660-4601/17/14/5248
• ISSN: 1661-7827; 1660-4601

Rice blast caused by <i>Magnaporthe oryzae</i> is one of the most serious rice diseases worldwide. Biological control is gaining popularity as a promising method for the control of this disease; however, more effective microbial strains with strong adaptability in rice fields need to be identified. Here, we report for the first time the successful identification of biocontrol bacterial strains from frozen soils of the soda saline-sodic land. We isolated 82 bacterial strains from rice fields in the western Songnen Plain of China, one of the three major soda saline soils in the world. Five of the isolated strains exhibited strong inhibition to <i>M. oryzae</i> growth. The potential strains were identified as <i>Bacillus safensis</i> JLS5, <i>Pseudomonas koreensis</i> JLS8, <i>Pseudomonas saponiphila</i> JLS10, <i>Stenotrophomonas rhizophila</i> JLS11 and <i>Bacillus tequilensis</i> JLS12, respectively, by 16s RNA gene sequence analysis. The antagonistic assay and the artificial inoculation tests showed that JLS5 and JLS12 could effectively inhibit conidial germination and pathogenicity of the rice blast fungus, both preventively and curatively. The suppression of pathogenicity was further confirmed by greenhouse experiments, showing the effectiveness of JLS5 and JLS12 as a potential biological control agents of <i>M. oryzae</i>. The potential application of these cold-tolerant strains for rice blast control in cold regions is discussed. Our data suggest that soda saline-sodic soils are a rich source for biocontrol strain isolation.