title: A spindle pole antigen gene MoSPA2 is important for polar cell growth of vegetative hyphae and conidia, but is dispensable for pathogenicity in Magnaporthe oryzae.
abstract: Spa2 is an important component of the multiprotein complex polarisome, which is involved in the establishment, maintenance, termination of polarized cell growth and is important for defining tip growth of filamentous fungi. In this study, we isolated an insertional mutant of the rice blast fungus Magnaporthe oryzae that formed smaller colony and conidia compared with the wild type. In the mutant, a spindle pole antigen gene MoSPA2 was disrupted by the integration of an exogenous plasmid. Targeted gene deletion and complementation assays demonstrated the gene disruption was responsible for the defects of the insertional mutant. Interestingly, the MoSpa2-GFP fusion protein was found to accumulate as a spot at hyphal tips, septa of hyphae and conidial tip cells where germ tubes are usually produced, but not in appressoria, infection hyphae or at the septa of conidia. Furthermore, the deletion mutants of MoSPA2 exhibited slower hyphal tip growth, more hyphal branches, and smaller size of conidial tip cells. However, MoSPA2 is not required for plant infection. These results indicate that MoSPA2 is required for vegetative hyphal growth and maintaining conidium morphology and that spotted accumulation of MoSpa2 is important for its functions during cell polar growth.
authors.affiliation: Ministry of Agriculture Key Laboratory of Plant Pathology, Department of Plant Pathology, China Agricultural University, Beijing, 100193, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: Xiao-Lin
authors.initials: XL
authors.lastname: Chen
authors.forename: Jin-Guang
authors.initials: JG
authors.lastname: Huang
authors.forename: Zhi-Hua
authors.initials: ZH
authors.lastname: Cheng
authors.forename: Wen-Sheng
authors.initials: WS
authors.lastname: Zhao
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: You-Liang
authors.initials: YL
authors.lastname: Peng
mesh_terms: D000946:Antigens, Fungal / Q000276:immunology*; D016764:Cell Polarity; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D025301:Hyphae; D020082:Magnaporthe / Q000235:genetics / Q000254:growth & development / Q000276:immunology / Q000472:pathogenicity; D016254:Mutagenesis, Insertional; D012275:Oryza / Q000382:microbiology*; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D017384:Sequence Deletion; D064047:Spindle Poles / Q000378:metabolism; D013172:Spores, Fungal; D014774:Virulence
chemical_list: D000946:Antigens, Fungal; D005656:Fungal Proteins