Plant, Animal & Microbe Genomes X Conference

January 12-16, 2002
Town & Country Convention Center
San Diego, CA

Poster: Functional Genomics for Microorganisms
            

TRANSFER OF HYGROMYCIN B RESISTANCE TO CERCOSPORA BETICOLA USING AGROBACTERIUM TUMEFACIENS.

¹ USDA-ARS, Red River Valley Agricultural Research Center, Fargo, N.D. 58105 USA

² Department of Plant Pathology, North Dakota State University, Fargo, N.D. 58105

The imperfect filamentous fungus Cercospora beticola Sacc. causes a devastating leaf spot disease of sugarbeet in humid production regions of the world. Previous work on Cercosporoid fungi has revealed the importance of non-host-specific phytotoxins, including cercosporin, in virulence and pathogenicity in this economically-important group of fungi. In the most recent of these investigations the application of gene transfer technology has proven highly useful. Few of these results, however, have been produced in studies directly involving C. beticola, in part due to the lack of an efficient gene transfer system for this fungus. In the present study, Agrobacterium tumefaciens strain EHA-105 was used in an attempt to transform C. beticola to hygromycin B resistance. The binary vector pBIN19 was modified to encode, between the T-DNA borders, the hygromycin B phosphotransferase (hpt) gene under the control of a fungal transcription promoter and terminator. Co-cultivation of a mixture of C. beticola conidia and conidiophores along with the virulent A. tumefaciens resulted in the generation of C. beticola colonies resistant to hygromycin B at a concentration of 50 ug/ml. Presence of the transferred DNA was confirmed by amplification of the hpt gene sequences using the polymerase chain reaction and primers directed to hpt gene sequences. Use of this transformation system in analyzing the genetics of pathogenicity and virulence of this important pathogen of sugarbeet will be discussed.