Genes under positive selection in a model plant pathogenic fungus, Botrytis

► ESTs were sequenced in the fungal pathogens Botrytis tulipae and Botrytis ficariarum. ► Six-hundred and forty two orthologs were found by comparing these ESTs and complete genomes of two closely related species. ► A maximum likelihood analysis detected 21 genes evolving under positive selection. ► The gene encoding the phytotoxic protein BcPLS1 evolved under positive selection. ► Mutants of Botrytis cinerea were generated to elucidate the functions of three other genes.