conidia with the plasmid pAN7-1. (A) Untransformed conidia grown normally on non-treated zucchini cotyledons. (B-C) Transformants of P. xanthii grown on zucchini cotyledons treated with hygromycin B after electroporation of conidia with the plasmid pAN7-1. Note the reduced size of the colonies compared with untransformed colonies. No colonies were observed on cotyledons treated with hygromycin B and inoculated with untransformed conidia. (D) In many cases, treatment with hygromycin B induced phytotoxicity (necrotic spots) on cotyledons. Pictures were taken 15 d after electroporation of conidia.