Histidine kinases mediate differentiation, stress response, and pathogenicity inMagnaporthe oryzae

• DOI: 10.1002/mbo3.197
• Publication Date: 2014-08-08T05:57:53Z
• Authors: Stefan Jacob; Andrew J. Foster; Alexander Yemelin; Eckhard Thines
• Keywords: 0303 health sciences; Histidine Kinase; Virulence; Oryza; Spores, Fungal; Fungal Proteins; Magnaporthe; 03 medical and health sciences; Gene Expression Regulation, Fungal; Multigene Family; Protein Kinases; Original Research; Plant Diseases

AbstractThe aim of this study is a functional characterization of 10 putative histidine kinases (HIKs)‐encoding genes in the phytopathogenic fungusMagnaporthe oryzae. TwoHIKs were found to be required for pathogenicity in the fungus. It was found that the mutant strainsΔMohik5andΔMohik8show abnormal conidial morphology and furthermoreΔMohik5is unable to form appressoria. BothHIKs MoHik5p and MoHik8p appear to be essential for pathogenicity since the mutants fail to infect rice plants. MoSln1p and MoHik1p were previously reported to be components of theHOGpathway inM. oryzae. TheΔMosln1mutant is more susceptible to salt stress compared toΔMohik1, whereasΔMohik1appears to be stronger affected by osmotic or sugar stress. In contrast to yeast, theHOGsignaling cascade in phytopathogenic fungi apparently comprises more elements. Furthermore, vegetative growth of the mutantsΔMohik5andΔMohik9was found to be sensitive to hypoxia‐inducing NaNO2‐treatment. Additionally, it was monitored that NaNO2‐treatment resulted in MoHog1p phosphorylation. As a consequence we assume a first simplified model for hypoxia signaling inM. oryzaeincluding theHOGpathway and theHIKs MoHik5p and MoHik9p.