Transformation of the bioherbicide Colletotrichum gloeosporioides f. sp. aeschynomene by electroporation of germinated conidia

Abstract A highly ecient and reproducible procedure for the transformation of the bioherbicide Colletotri-chum gloeosporioides f. sp. aeschynomene by electropo-ration of germinated conidia is reported. Development of the procedure involved a detailed study of the ger-mination process followed by extensive calibration of the electrical-pulse and selection conditions. Optimiza-tion of the transformation protocol was facilitated by the use of the green fluorescent protein that helped in the identification of stable transformants and in a fast as-sessment of transgene expression levels, colony homo-geneity and genetic stability. Under optimal conditions, over 80 stable transformants/cuvette were obtained. Plasmid integration was predominantly homologous, but high transformation rates were obtained both with homologous and non-homologous vectors. The method described not only opens up opportunities for the ge-netic manipulation of C. gloeosporioides f. sp. aeschy-nomene, but also provides a framework for the develop-ment and optimization of transformation in other fungi. Key words Electroporation á Fungal transformation á GFP á Mycoherbicide