A P-type ATPase required for rice blast disease and induction of host resistance.

To cause diseases in plants, pathogenic microorganisms have evolved mechanisms to deliver proteins directly into plant cells, where they suppress plant defences and facilitate tissue invasion. How plant pathogenic fungi, which cause many of the world's most serious plant diseases, deliver proteins during plant infection is currently unknown. Here we report the characterization of a P-type ATPase-encoding gene, MgAPT2, in the economically important rice blast pathogen Magnaporthe grisea, which is required for exocytosis during plant infection. Targeted gene replacement showed that MgAPT2 is required for both foliar and root infection by the fungus, and for the rapid induction of host defence responses in an incompatible reaction. DeltaMgapt2 mutants are impaired in the secretion of a range of extracellular enzymes and accumulate abnormal Golgi-like cisternae. However, the loss of MgAPT2 does not significantly affect hyphal growth or sporulation, indicating that the establishment of rice blast disease involves the use of MgApt2-dependent exocytotic processes that operate during plant infection.