Genetic Transformation System for the Fungal Soybean Pathogen Cercospora kikuchii.
An altered beta-tubulin gene that confers resistance to the fungicide benomyl was isolated from a genomic library of a UV-induced mutant of Cercospora kikuchii and used as a selectable marker for transformation. The level of benomyl resistance conferred to the transformants was at least 150-fold greater than the intrinsic resistance of the C. kikuchii recipient protoplasts. In the majority of cases, the tubulin fragment was integrated at the native beta-tubulin locus, apparently by gene replacement or gene conversion. The frequency of transformation ranged from 0.2 to 6 transformants per mug of DNA, depending on the recipient strain. Transformation with linearized plasmid resulted in a higher frequency, without changing the type of integration event. Transformants were phenotypically stable after eight consecutive transfers on medium without benomyl. This is the first report of a genetic transformation system for a Cercospora species.
Upchurch
R G
RG
Agricultural Research Service, U.S. Department of Agriculture, and Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695-7616.
Ehrenshaft
M
M
Walker
D C
DC
Sanders
L A
LA