Ultrastructural markers and systematics in smut fungi and allied taxa

Abstract

To identify monophyletic groups within the smut fungi and related taxa, characteristics of hyphal septation and zones of host–parasite interaction were analyzed by serial-section electron microscopy of 139 species belonging to 50 smut and 10 allied genera. Our results support the hypothesis of the existence of two phylogenetically separate lines of smut fungi. The first line, the Microbotryales, is composed of Aurantiosporium, Fulvisporium, Liroa, Microbotryum, Sphacelotheca, and Ustilentyloma, which are distributed into the Ustilentylomataceae and Microbotryaceae. The second monophyletic line, the Ustilaginomycetes, is formed by the remaining smut fungi studied here together with the Exobasidiales, Graphiolales, and Cryptobasidiales (in the traditional sense). The ultrastructural analysis identifies three lineages within the Ustilaginomycetes. The Entorrhizomycetidae are represented by Entorrhiza. The Ustilaginomycetidae consist of the Urocystales and Ustilaginales. The Exobasidiomycetidae are composed of the Doassansiales, Entylomatales, Exobasidiales, Georgefischeriales, Graphiolales, Microstromatales, and Tilletiales. The Entorrhizomycetidae, Exobasidianae, Entorrhizales, Entylomatales, Doassansiales, Georgefischeriales, Microbotryales, Microstromatales, Tilletiales, Urocystales, Entorrhizaceae, Entylomataceae, Georgefischeriaceae, Mycosyringaceae, Rhamphosporaceae, and Ustilentylomataceae are proposed as new taxa. The descriptions of the Exobasidiomycetidae, Ustilaginomycetidae, Exobasidiales, Ustilaginales, Doassansiaceae, Tilletiaceae, and Ustilaginaceae are emended. Some species of Ustilago are transferred to Microbotryum. Key words: basidiomycetes, classification, Exobasidiales, Graphiolales, phylogeny, smut fungi, ultrastructure.

Endoplasmic Reticulum Glucosidase II Is Required for Pathogenicity ofUstilago maydis [W]

“…Using transmission electron microscopy, the host-pathogen interface of invading wild-type hyphae was visualized ( Figure 7C). As shown before for a variety of smut fungi, the interaction zone is electron opaque (Bauer et al, 1997), can be seen between the host plasma membrane and the fungal cell wall ( Figure 7C, asterisks), and has also previously been described for U. maydis (Snetselaar and Mims, 1994). The wild-type hyphae were typically surrounded by host cells containing normal-appearing (A) Appressoria visualized by leaf staining with calcofluor 1 d after infection of young maize seedlings with a combination of wild-type (FB1 and FB2) or Dgas1 strains (HBU13 and HBU14).…”

Biodiversity and systematics of basidiomycetous yeasts as determined by large-subunit rDNA D1/D2 domain sequence analysis.

“…The order Microbotryales was formally described by Bauer et al (1997) as ' phytoparasitic members of the Basidiomycota having transversely septate basidia with multiple production of sessile basidiospores and only intercellular hyphae. ' These authors divided the order into two families, i.e.…”

“…Consequently, the Microbotryum clade is phylogenetically diverse, as reflected by the lack of bootstrap support for the clade and for many of the internal clusters. A unifying characteristic within this clade is the presence of colacosomes or lenticular bodies, which are an indication of mycoparasitism (Bauer & Oberwinkler, 1991 ;Bauer et al, 1997 ;Boekhout et al, 1992).…”

Eukaryotic Biodiversity in Mixed Peat Ecosystems in Sarawak, Malaysia

“…The Ustilaginomycotina is a subdivision within the division Basidiomycota which has 1400 recognised species in 70 genera. It consists of the classes Ustilaginomycetes and Exobasidiomycetes (Bauer, 1997), and in 2014 the subdivision was reclassified and the two additional classes Malasseziomycetes and Moniliellomycetes (Wang et al, 2014).…”