Secreted protein required for appressorial penetration of intact host epidermal cells and for pathogenicit, but not for subsequent biotrophic and necrotrophic colonization of leaves. Homodimer; disulfide-linked (Probable). Dimerization can possibly extend to multimerisation (Probable). Expressed at all stages of pathogenesis. Impairs pathogenicity (PubMed:31599055). Forms pressurised appressoria but is hampered in forming penetration pores and fails to differentiate a penetration peg (PubMed:31599055). Belongs to the MC69 virulence factor family.