Rice Blast, caused by the ascomycete fungus Magnaporthe
oryzae, is one of the most devastating diseases on cultivated rice worldwide, and the annual lose in
rice production from Rice Blast is estimated to be enough to feed more than 60
million people. In M. oryzae,
multiple signaling pathways are involved in pathogenicity, including the mitogen-activated
protein kinase (MAPK) pathways. PMK1 MAPK pathway regulates the appressorium
formation and MPS1 MAPK pathway is require for the maintenance of cell wall
integrity. The third MAPK OSM1 pathway is involved in osmotic
stress response and essential for fungal survival in natural habitats. My
research has focused on Mst50, which previously identified as an adaptor
protein in the PMK1 pathway and essential
for appressorium formation. My goal was
to better understand the role of Mst50 in the signaling pathways associated cell
wall integrity and osmotic stress response. In this study, I used a protein
affinity approach to identify components that interacted with Mst50 in vivo. My results indicate that Mst50
regulates the MPS1 cell wall integrity MAPK pathway by interacting with Mck1, the MAPKKK in this pathway.
Mst50 is also involved in osmotic regulation by interacting with histidine
kinase Hik1 in the MAPK OSM1 pathway.
This study illustrates how Mst50 functions as an important adaptor protein across
multiple signaling pathways in M. oryzae.