Abstract
ABSTRACTFap7, an important ribosome assembly factor, plays a vital role in pre-40S small ribosomal subunit synthesis in Saccharomyces cerevisiae via its ATPase activity. Currently, the biological functions of its homologs in filamentous fungi remain elusive. Here, MoFap7, a homologous protein of ScFap7, was identified in the rice blast fungus Magnaporthe oryzae, which is a devastating fungal pathogen in rice and threatens food security worldwide. ΔMofap7 mutants exhibited defects in growth and development, conidial morphology, appressorium formation and infection, and were sensitive to oxidative stress. In addition, site-directed mutagenesis analysis confirmed that the conserved Walker A motif and Walker B motif in MoFap7 are essential for the biological functions of M. oryzae. We further analyzed the regulation mechanism of MoFap7 in pathogenicity. MoFap7 was found to interact with MoMst50, a regulator functioning in the MAPK Pmk1 signaling pathway, that participates in modulating plant penetration and cell-to-cell invasion by regulating the phosphorylation of MoPmk1. Moreover, MoFap7 interacted with the GTPases MoCdc42 and MoRac1 to control growth and conidiogenesis. Taken together, the results of this study provide novel insights into MoFap7-mediated orchestration of the development and pathogenesis of filamentous fungi.
Highlights
Magnaporthe oryzae is a filamentous plant pathogenic fungus that infects many kinds of crops including rice and barley, and causes rice blast and wheat blast
Using CLUSTALW to align the amino acids of Fap7 in Magnaporthe oryzae (MoFap7), Fusarium graminearum (XP_011327243.1), Neurospora crassa (XP_001728530.2), Saccharomyces cerevisiae (NP_010115.1), Mus musculus (NP_081868.1), Caenorhabditis elegans (NP_496065.1) and Homo sapiens (NP_057367.1)
The conidial morphology of the complemented strain was restored to normal (Figure 3(f)). These results suggested that MoFap7 is required for vegetative growth and conidiogenesis in M. oryzae
Summary
Magnaporthe oryzae is a filamentous plant pathogenic fungus that infects many kinds of crops including rice and barley, and causes rice blast and wheat blast. Three MAPK pathways are involved in regulating invasive growth, appressprium formation, cell wall integrity, and surface recognition in M. oryzae [8]. In M. oryzae, MoMst is an important component of the PMK1 signaling pathway, and ΔMomst mutants have similar defects to ΔMopmk mutants in terms of appressorium formation and plant infection, functioning as adaptor proteins in the MoMst11MoMst7-MoPmk cascade [18,19]. In S. cerevisiae, Cdc functions in the transduction of polarity signals to the morphogenetic machinery [25,26] In pathogenic fungi such as Claviceps purpurea, Ustilago maydis and Colletotrichum trifolii, deletion of Cdc results in abnormal morphology of certain cell types, such as conidia, and nonpathogenicity to the plant host [27,28]. Since Fap is an important protein with dual functions of adenylate kinase and GTPase activity, the null mutant in yeast is lethal [44]. MoFap is able to interact with MoMst, regulating the phosphorylation of MoPmk, which is important for plant infection and cellto-cell invasion [16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
