The small GTPase BcCdc42 affects nuclear division, germination and virulence of the gray mold fungus Botrytis cinerea

► Bccdc42, the cdc42 homologue of Botrytis cinerea, was functionally analyzed. ► BcCdc42 has impact on form and germination of conidia and sclerotia formation. ► cdc42 mutants show disturbed nuclear division and migration in germ tubes. ► BcCdc42 is necessary for penetration and colonization of plant tissue.