A single fungal MAP kinase controls plant cell-to-cell invasion by the rice blast fungus

Keeping the channels open When the rice blast fungus enters a rice cell, the plasma membrane stays intact, so the rice cell remains viable. The fungus then moves to adjacent cells via plasmodesmata, the plant's intercellular channels. Sakulkoo et al. used a chemical genetic approach to selectively inhibit a single MAP (mitogen-activated protein) kinase, Pmk1, in the blast fungus. Inhibition of Pmk1 trapped the fungus within a rice cell. Pmk1 regulated the expression of a suite of effector genes involved in suppression of host immunity, allowing the fungus to manipulate plasmodesmal conductance. At the same time, Pmk1 regulated the fungus's hyphal constriction, which allows movement into new host cells. Science , this issue p. 1399