Exploiting endophytic bacteria for the management of sheath blight disease in rice

Abstract

Sheath blight of rice caused by Rhizoctonia solani Kuhn is an important soil-borne disease throughout the rice-producing areas of the world. Twenty-nine bacterial endophytes were isolated from different plant sources and tested for their efficacy against R. solani inciting sheath blight in rice. Bacillus subtilis var. amyloliquefaciens (FZB24) caused a maximum 36% inhibition of R. solani over the control in vitro. Rice plants (cv. ADT 39) treated with FZB24, in combination with seed treatment @ 4 g kg^− 1, seedling dip @ 4 g l^− 1, soil application @ 500 g ha^− 1 and foliar application @ 500 g ha^− 1, gave the lowest severity of sheath blight (33%) with around 55% reduction over the control under glasshouse conditions. In addition, the B. subtilis (FZB24) treated rice plants showed higher induction of defence-related enzymes, peroxidase, polyphenol oxidase and phenylalanine ammonia lyase, and resulted in higher accumulation of total phenols than in the untreated control plants. The endophyte-treated rice plots had a significantly lower intensity of sheath blight than untreated control plots and also recorded a higher grain and straw yield.

Keywords::

• Bacillus
• endophytes
• induced systemic resistance
• Rhizoctonia solani
• rice sheath blight

Acknowledgements

The authors are grateful to M/S. Novozymes South Asia for their financial assistance in carrying out this work.