A novel F-box protein involved in sexual development and pathogenesis in Gibberella zeae.
Gibberella zeae is an ascomyceteous fungus that causes serious diseases in cereal crops. Severe epidemics require strains that are virulent and that can reproduce sexually. We characterized an insertional mutant (designated ZH436) with a pleiotropic defect in both traits, and identified a novel F-box protein gene encoding FBP1 (F-box protein 1) that is similar to fungal F-box proteins including Saccharomyces cerevisiae Grr1, a well-characterized component of the Skp1-Cullin-F-box protein (SCF(Grr1)) E3 ligase complex required for protein degradation. FBP1 also can bind both S. cerevisiae Skp1 protein, the other component of the SCF(Grr1) complex, and its G. zeae sequence homologue SKP1. Two putative protein interacting domains in FBP1 are essential for in vivo function. FBP1 and ScGRR1 are not so interchangeable between S. cerevisiae and G. zeae, but FBP1 can partially complement several defects of a yeast grr1 deletion mutant. Functional analyses confirmed that FBP1 is required for several phenotypes including both sexual development and virulence in G. zeae; the phenotype of DeltaFBP1 strains is different from those of null mutants for F-box proteins in other filamentous fungi as well as from S. cerevisiae grr1Delta strains. Thus, FBP1 is a versatile F-box protein that presumably participates in the formation of the SCF(FBP1) complex that probably controls the ubiquitin-mediated degradation of proteins involved in sexual reproduction and virulence important for disease development by G. zeae.
Han
You-Kyoung
YK
School of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921, Korea.
Kim
Myoung-Dong
MD
Lee
Seung-Ho
SH
Yun
Sung-Hwan
SH
Lee
Yin-Won
YW
D000595:Amino Acid Sequence; D044783:F-Box Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D005874:Gibberella / Q000254:growth & development* / Q000378:metabolism / Q000472:pathogenicity*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010641:Phenotype; D017434:Protein Structure, Tertiary; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
D044783:F-Box Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D044843:SKP Cullin F-Box Protein Ligases