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Disease Detection and Losses

The Use of Isozymes to Identify Teliospores of Tilletia indica. M. R. Bonde, Research plant pathologist, USDA, Agricultural Research Service, Foreign Disease-Weed Science Research, Ft. Detrick, Building 1301, Frederick, MD 21701; G. L. Peterson(2), and T. T. Matsumoto(3). (2)Biological laboratory technician, USDA, Agricultural Research Service, Foreign Disease-Weed Science Research, Ft. Detrick, Building 1301, Frederick, MD 21701; (3)Plant pathologist, Department of Food and Agriculture, California Department of Agriculture, 1220 N Street, Sacramento 95814. Phytopathology 79:596-599. Accepted for publication 16 December 1988. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1989. DOI: 10.1094/Phyto-79-596.

Single-teliospore cultures of Tilletia indica, causal agent of Karnal bunt of wheat, were examined by horizontal starch gel electrophoresis and staining for 50 enzymes. Thirty-two were present in high concentrations and could be resolved. Of 36 presumed isozyme loci, 15 (42%) were polymorphic (having allelic variation) among cultures. The high number of alleles in common (Rogers’ coefficient of similarity = 0.83) among isolates of T. indica facilitated their differentiation from those of Tilletia barclayana, the causal agent of kernel smut of rice. Teliospores of the latter are frequently confused with those of T. indica. The average coefficient of similarity comparing T. indica with T. barclayana was extremely low (0.04), emphasizing the large difference in their isozymes. Isozymes are being used at the Foreign Disease-Weed Science Research Unit to distinguish between teliospores of T. indica and T. barclayana in stored grain, storage facilities, and transportation vehicles.