title: MST50 is involved in multiple MAP kinase signaling pathways in Magnaporthe oryzae.
abstract: Appressorium formation plays a critical role in Magnaporthe oryzae. Mst50 is an adapter protein of the Mst11-Mst7-Pmk1 cascade that is essential for appressorium formation. To further characterize its functions, affinity purification was used to identify Mst50-interacting proteins (MIPs) in this study. Two of the MIPs are Mst11 and Mst7 that are known to interact with Mst50 for Pmk1 activation. Surprisingly, two other MIPs are Mck1 and Mkk2 that are the upstream kinases of the Mps1 pathway. Domain deletion analysis showed that the sterile alpha-motif of Mst50 but not the Ras-association domain was important for its interaction with Mck1 and responses to cell wall and oxidative stresses. The mst50 mutant was reduced in Mps1 activation under stress conditions. MIP11 encodes a RACK1 protein that also interacted with Mck1. Deletion of MIP11 resulted in defects in cell wall integrity, Mps1 phosphorylation and plant infection. Furthermore, Mst50 interacted with histidine kinase Hik1, and the mst50 mutant was reduced in Osm1 phosphorylation. These results indicated that Mst50 is involved in all three MAPK pathways in M. oryzae although its functions differ in each pathway. Several MIPs are conserved hypothetical proteins and may be involved in responses to various signals and crosstalk among signaling pathways.
authors.affiliation: Purdue-NWAFU Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China.|Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA.
authors.forename: Guotian
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA.
authors.forename: Xue
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Purdue-NWAFU Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Tian
authors.affiliation: Division of Environmental Science and Ecological Engineering, College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, Republic of Korea.
authors.forename: Yoon-E
authors.initials: YE
authors.lastname: Choi
authors.affiliation: Department of Biochemistry, Purdue University, West Lafayette, IN, 47907, USA.
authors.forename: W Andy
authors.initials: WA
authors.lastname: Tao
authors.affiliation: Purdue-NWAFU Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China.|Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA.
authors.forename: Jin-Rong
authors.initials: JR
authors.lastname: Xu
mesh_terms: D002473:Cell Wall / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000235:genetics*; D020082:Magnaporthe / Q000235:genetics* / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D012275:Oryza / Q000382:microbiology*; D010766:Phosphorylation; D010935:Plant Diseases / Q000382:microbiology; D015398:Signal Transduction
chemical_list: D005656:Fungal Proteins; D020928:Mitogen-Activated Protein Kinases; C102726:Pmk1 protein, Magnaporthe grisea