title: Genetic and Pathogenic Variability of Fusarium oxysporum f. sp. cepae Isolated from Onion and Welsh Onion in Japan.
abstract: Fusarium oxysporum f. sp. cepae causes Fusarium basal rot in onion (common onion) and Fusarium wilt in Welsh onion. Although these diseases have been detected in various areas in Japan, knowledge about the genetic and pathogenic variability of F. oxysporum f. sp. cepae is very limited. In this study, F. oxysporum f. sp. cepae was isolated from onion and Welsh onion grown in 12 locations in Japan, and a total of 55 F. oxysporum f. sp. cepae isolates (27 from onion and 28 from Welsh onion) were characterized based on their rDNA intergenic spacer (IGS) and translation elongation factor-1α (EF-1α) nucleotide sequences, vegetative compatibility groups (VCGs), and the presence of the SIX (secreted in xylem) homologs. Phylogenetic analysis of IGS sequences showed that these isolates were grouped into eight clades (A to H), and 20 onion isolates belonging to clade H were monophyletic and assigned to the same VCG. All the IGS-clade H isolates possessed homologs of SIX3, SIX5, and SIX7. The SIX3 homolog was located on a 4 Mb-sized chromosome in the IGS-clade H isolates. Pathogenicity tests using onion seedlings showed that all the isolates with high virulence were in the IGS-clade H. These results suggest that F. oxysporum f. sp. cepae isolates belonging to the IGS-clade H are genetically and pathogenically different from those belonging to the other IGS clades.
authors.affiliation: First author: The United Graduate School of Agricultural Sciences, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8553, Japan; and second, third, fourth, and fifth authors: Department of Biological and Environmental Sciences, Faculty of Agriculture, Yamaguchi University, Yamaguchi, 753-8515, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Sasaki
authors.forename: Katsuya
authors.initials: K
authors.lastname: Nakahara
authors.forename: Shuhei
authors.initials: S
authors.lastname: Tanaka
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Shigyo
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Ito
mesh_terms: D001483:Base Sequence; D002874:Chromosome Mapping; D017931:DNA Primers / Q000235:genetics; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005670:Fusarium / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D005819:Genetic Markers / Q000235:genetics; D007564:Japan; D008969:Molecular Sequence Data; D019697:Onions / Q000382:microbiology*; D020648:Peptide Elongation Factor 1 / Q000235:genetics; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology*; D018517:Plant Roots / Q000382:microbiology; D036226:Seedlings / Q000235:genetics; D017422:Sequence Analysis, DNA; D014774:Virulence / Q000235:genetics
chemical_list: D017931:DNA Primers; D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D005819:Genetic Markers; D020648:Peptide Elongation Factor 1