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

A highly efficient and reproducible procedure for the transformation of the bioherbicide Colletotrichum gloeosporioides f. sp. aeschynomene by electroporation of germinated conidia is reported. Development of the procedure involved a detailed study of the germination process followed by extensive calibration of the electrical-pulse and selection conditions. Optimization 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 assessment of transgene expression levels, colony homogeneity 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 genetic manipulation of C. gloeosporioides f. sp. aeschynomene, but also provides a framework for the development and optimization of transformation in other fungi.