title: Molecular phylogenetic analyses based on the nuclear rRNA genes and the intron-exon structures of the nuSSU rRNA gene in Dictyocatenulata alba (anamorphic Ascomycota).
abstract: Molecular phylogenies inferred from the nuclear small subunit rRNA gene (nuSSU), nuclear large subunit rRNA gene D1/D2 region (nuLSU), and ITS-5.8S rRNA gene (ITS) indicated that five cultures of the lichenized hyphomycete Dictyocatenulata alba isolated from Japan form a monophyletic clade with high bootstrap support, and a close relationship to the Ostropomycetidae (Lecanoromycetes, Pezizomycotina, Ascomycota). Insertion sequences were found in the nuSSU of all isolates [e.g., nine insertions in the strain JCM 5358 (Japan Collection of Microorganisms)], some of which were group I introns. Five new insertion positions were found among the D. alba isolates. Using BLAST, none of the insertion sequences of D. alba were closely related to those of fungi or other organisms deposited in public DNA databases. Insertion positions were similar in some isolates, and two positions were common to all isolates. Although all phylogenetic analyses based on nuSSU, nuLSU, and ITS revealed the monophyly of D. alba, the isolates were divided into two (in the nuSSU tree) or three (in the nuLSU and ITS trees) groups. Based on the phylogenetic analyses and the intron-exon structures, the five isolates identified as D. alba belong to three cryptic species and therefore D. alba should be considered a species complex. The very slow-growing, tough agar colonies of the isolates, the occurrence of the species on both slightly lichenized and nonlichenized surfaces of trees, or pebbles (rarely on soil), suggest that the members of the D. alba complex may be lichenized. The photobiont was not clearly identified in this study.
authors.affiliation: Microbe Division/Japan Collection of Microorganisms, RIKEN BioResource Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Kwang-Deuk
authors.initials: KD
authors.lastname: An
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Degawa
authors.forename: Eriko
authors.initials: E
authors.lastname: Fujihara
authors.forename: Takashi
authors.initials: T
authors.lastname: Mikawa
authors.forename: Moriya
authors.initials: M
authors.lastname: Ohkuma
authors.forename: Gen
authors.initials: G
authors.lastname: Okada
mesh_terms: D001203:Ascomycota / Q000145:classification / Q000235:genetics* / Q000648:ultrastructure; D001483:Base Sequence; D004251:DNA Transposable Elements / Q000235:genetics; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005091:Exons; D007438:Introns; D008969:Molecular Sequence Data; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment
chemical_list: D004251:DNA Transposable Elements; D004271:DNA, Fungal; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D012335:RNA, Ribosomal