The present invention relates to a method for modifying the resistance profile of a spinach plant to Peronospora farinosa f. sp. spinaciae, comprising introducing a WOLF allele or a resistance-conferring part thereof into the genome of said spinach plant, or modifying an endogenous WOLF allele in the genome of said spinach plant. The invention further provides a method for selecting a spinach plant comprising a novel WOLF gene that confers resistance to Peronospora farinosa f. sp. spinaciae in a spinach plant and a method for identifying a WOLF allele that confers resistance to one or more pathogenic races of Peronospora farinosa f. sp. spinaciae in a spinach plant and to primers for use in these methods.