Colletotrichum graminicola Transformed with Homologous and Heterologous Benomyl-Resistance Genes Retains Expected Pathogenicity to Corn. Daniel G. Panaccione. Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907 U.S.A.. Martin McKiernan, and Robert M. Hanau. Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907 U.S.A.. MPMI 1:113-120. Accepted 7 March 1988. Copyright 1988 The American Phytopathological Society.

Colletotrichum graminicola was efficiently transformed to benomyl resistance by ß-tubulin genes cloned from C. graminicola and Neurospora crassa benomyl-resistant mutants. Southern blot hybridizations showed that the ß-tubulin genes used as selectable markers share homology with distinct regions of the C. graminicola genome, suggesting the presence of two divergent ß-tubulin genes in the fungus. Plasmids containing either selectable marker integrated at a variety of loci and were often present in more than one copy per genome. Plasmid integration was not detected in genomic sequences with homology to the selectable markers. The benomyl-resistant phenotype of transformants was highly stable during in vitro culture in the absence of selection. In addition, the benomyl-resistant phenotype persisted in isolates recovered from susceptible corn seedlings that had been inoculated with transformants. When transformants obtained with either selectable marker were used to inoculate susceptible and resistant corn seedlings, each produced symptoms typical of those caused by the untransformed, parental strain.