title: Heterokaryon analysis of a Cdc48-like gene, CpCdc48, from the chestnut blight fungus Cryphonectria parasitica demonstrates it is essential for cell division and growth.
abstract: Functional analysis of a cell division cycle 48 (CDC48) ortholog, CpCdc48, from Cryphonectria parasitica was performed via construction of a CpCdc48-null mutant. Genotype analysis revealed that the putative CpCdc48-null mutant was a heterokaryotic transformant containing two different types of nuclei (i.e., one with the wild-type CpCdc48 allele and the other with the CpCdc48-null mutant allele). Although stable mycelial growth of the heterokaryotic transformant was observed on media containing hygromycin B, neither germination nor growth of the resulting spores was observed on selection media, suggesting that the CpCdc48 gene is essential. Microscopic analysis of germinated conidia from the heterokaryon demonstrated that although there were normal germinating spores due to the wild-type conidia, there were many residual conidia that did not germinate. However, with prolonged incubation, non-germinating conidia began to swell into gigantic globose spores. DAPI staining and FACS analysis of the gigantic spores revealed the presence of multiple nuclei. These gigantic conidia did not show any signs of polarized growth and underwent autolysis with further incubation. These findings indicate that the CpCdc48 gene is responsible for delayed cell cycle during spore germination, resulting in some karyokinesis, but not following spore cytokinesis. Thus, CpCdc48 is essential for cell division and polarized growth.
authors.affiliation: Department of Molecular Biology, Department of Bioactive Material Sciences, Center for Fungal Pathogenesis, Chonbuk National University, Jeonju, Chonbuk 561-756, Republic of Korea.
authors.forename: Yo-Han
authors.initials: YH
authors.lastname: Ko
authors.affiliation: Department of Molecular Biology, Department of Bioactive Material Sciences, Center for Fungal Pathogenesis, Chonbuk National University, Jeonju, Chonbuk 561-756, Republic of Korea.
authors.forename: Kum-Kang
authors.initials: KK
authors.lastname: So
authors.affiliation: Department of Bio-Environmental Chemistry, Wonkwang University, Iksan, Chonbuk 570-749, Republic of Korea.
authors.forename: Jung-Mi
authors.initials: JM
authors.lastname: Kim
authors.affiliation: Department of Molecular Biology, Department of Bioactive Material Sciences, Center for Fungal Pathogenesis, Chonbuk National University, Jeonju, Chonbuk 561-756, Republic of Korea. Electronic address: dhkim@jbnu.ac.kr.
authors.forename: Dae-Hyuk
authors.initials: DH
authors.lastname: Kim
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000502:physiology; D000483:Alleles; D001203:Ascomycota / Q000235:genetics* / Q000254:growth & development* / Q000502:physiology; D002453:Cell Cycle / Q000235:genetics; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics; D005800:Genes, Fungal; D005838:Genotype; D008938:Mitosis / Q000235:genetics; D009154:Mutation; D013172:Spores, Fungal / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D000074405:Valosin Containing Protein; D014774:Virulence / Q000235:genetics
chemical_list: D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D000251:Adenosine Triphosphatases; D000074405:Valosin Containing Protein
keywords: Cdc48; Cryphonectria parasitica; Heterokaryon; Hypovirulence