Mitogen-activated protein kinase kinase; part of the MST11-MST7-PMK1 MAP kinase (MAPK) cascade that is essential for appressorium formation, penetration and invasive growth. The MST11-MST7-PMK1 MAP kinase cascade transduces signals from the cell surface sensors MDB2 and SHO1 that recognize various surface signals such as surface hydrophobicity, cutin monomers, and rice leaf waxes. MST7 acts as the upstream MAPKK that directly phosphorylates MAP kinase PMK1