Characterisation of antagonistic soil microbes against Rhizoctonia spp. and Sclerotium hydrophilum

Abstract

Rhizoctonia solani, R. oryzae-sativae and Sclerotium hydrophilum are responsible for sheath diseases of rice. Soil treatment measures with antagonist microbes have produced good results against various soil-borne fungi. The objective of this study included to find out the potential antagonist microbes from the paddy field soil. Ten different soil samples were collected from the disease-prone area of paddy field soil. Antagonist microbes were identified by 16S rRNA sequence analysis. Subsequent screening of antagonist microbes yield B. subtilis B37 and P. aeruginosa B258 as the potential antagonist microbes to control sheath diseases of rice in Myanmar. Bacillus subtilis strains induced the competition between antagonist and the tested fungi at the margin of the bacterial growth itself. However, P. aeruginosa induced the competition at a long range formed by the antibiotic of antagonist microbe. Bacillus subtilis B37 and P. aeruginosa B258 could be applicable in the control strategy of causal agents of rice sheath diseases in Myanmar.

Keywords:

• antagonist soil microbes
• biological control
• rice
• Rhizoctonia spp.

Acknowledgements

The authors gratefully acknowledge the financial support of the Japan Society for the Promotion of Science (JSPS). Suggestions and comments of Prof. Kazuo Ogata, Institute of Tropical Agriculture, Kyushu University, is also highly acknowledged.