Catalyzes the Claisen rearrangement of chorismate to prephenate (PubMed:33010586). May function both as an effector during plant infection and in the fungal tyrosine and phenylalanine biosynthesis pathways (PubMed:33010586). During infection it channels chorismate into the phenylpropanoid pathway, thereby decreasing the synthesis of the plant immune signal salicylic acid (Probable). Within fungal cells, it acts at the first branch point in the aromatic amino acid pathway where it steers biosynthesis towards phenylalanine and tyrosine, and away from tryptophan (Probable). chorismate = prephenate Contrary to classical chorismate mutases, is not subject to allosteric regulation by tryptophan or tyrosine (PubMed:33010586). Also not regulated by phenylalanine (PubMed:33010586). Metabolic intermediate biosynthesis; prephenate biosynthesis; prephenate from chorismate: step 1/1. Homodimer. Appears to be secreted despite an apparent lack of a secretory signal. Present during infection; expression is higher in hausturia than epiphytic mycelia.