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Host-Specific Toxin Production by Rhizoctonia solani, the Rice Sheath Blight Pathogen

December 1997 , Volume 87 , Number  12
Pages  1,258 - 1,263

P. Vidhyasekaran , T. Ruby Ponmalar , R. Samiyappan , R. Velazhahan , R. Vimala , A. Ramanathan , V. Paranidharan , and S. Muthukrishnan

First, second, third, fourth, fifth, sixth, and seventh authors: Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore 641 003, India; and eighth author: Department of Biochemistry, Kansas State University, Manhattan 66506

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Accepted for publication 27 August 1997.

Rhizoctonia solani, the rice sheath blight pathogen, produces a toxin that reproduces all symptoms of the disease. The toxin has been partially purified and it was found to be a carbohydrate containing glucose, mannose, N-acetylgalactosamine, and N-acetylglucosamine. The toxin was also detected in infected leaves. Highly virulent isolates produced more toxin than less virulent isolates. Several R. solani isolates from rice and one each from cotton and tomato produced a similar toxin. All rice cultivars tested were susceptible to the pathogen and sensitive to the toxin. Host specificity of the toxin has been demonstrated using hosts and nonhosts of the pathogen.

© 1997 The American Phytopathological Society