Limtongia gen. nov. for Zygozyma smithiae (Lipomycetaceae) (original) (raw)

Physiological characters, mating compatibility, PCR-RAPD fingerprints, mol% G+C content, DNA–DNA relatedness, and large-subunit and internal transcribed spacer rRNA gene sequences of strains assigned to the genus Zygoascus were re-examined. On the basis of those data, and after phylogenetic analyses, an emendation of Zygoascus hellenicus (type material is a cross of CBS 6736T×CBS 5839T) is proposed, comprising two novel anamorphic varieties, Candida steatolytica var. steatolytica (CBS 6736T) and C. steatolytica var. inositophila (CBS 5839T). A novel teleomorphic species, Zygoascus meyerae sp. nov. (type material is a cross of CBS 4099T×CBS 7521T) is described, together with two novel anamorphic varieties corresponding to it, Candida hellenica var. hellenica (CBS 4099T) and C. hellenica var. acidophila (CBS 7115T).

Phylogenetic relationships among the hymenomycetous yeasts in the Cryptococcus luteolus lineage of the Tremellales were examined based on sequence analyses of the 18S rRNA gene, 26S rRNA gene D1/D2 domain, internal transcribed spacer (ITS) region including 5.8S rRNA gene and mitochondrial cytochrome b gene. In addition to the Dioszegia clade, two clades represented by Bullera mrakii and Bullera sinensis, respectively, were revealed to be well-separated monophyletic groups in the lineage. These clades also exhibited distinguishable colony characters. Two new genera, Derxomyces gen. nov. (type species: Derxomyces mrakii comb. nov.) and Hannaella gen. nov. (type species: Hannaella sinensis comb. nov.), are proposed to accommodate the species in the B. mrakii and B. sinensis clades, respectively. Mainly based on D1/D2 and ITS sequence comparison, eight novel Derxomyces species were recognized from ballistoconidium-forming strains isolated from plant leaves. The new species and their type strains are as follows: Derxomyces boekhoutii (AS 2.3758T=CBS 10824T), Derxomyces hainanensis (AS 2.3467T=CBS 10820T), Derxomyces linzhiensis (AS 2.2668T=CBS 10827T), Derxomyces pseudocylindrica (AS 2.3778T=CBS 10826T), Derxomyces qinlingensis (AS 2.2446T=CBS 10818T), Derxomyces simaoensis (AS 2.3571T=CBS 10822T), Derxomyces wuzhishanensis (AS 2.3760T=CBS 10825T) and Derxomyces yunnanensis (AS 2.3562T=CBS 10821T).

Zygomycete fungi were classified as a single phylum, Zygomycota, based on sexual reproduction by zygospores, frequent asexual reproduction by sporangia, absence of multicellular sporocarps, and production of coenocytic hyphae, all with some exceptions. Molecular phylogenies based on one or a few genes did not support the monophyly of the phylum, however, and the phylum was subsequently abandoned. Here we present phylogenetic analyses of a genome-scale data set for 46 taxa, including 25 zygomycetes and 192 proteins, and we demonstrate that zygomycetes comprise two major clades that form a paraphyletic grade. A formal phylogenetic classification is proposed herein and includes two phyla, six subphyla, four classes and 16 orders. On the basis of these results, the phyla Mucoromycota and Zoopagomycota are circumscribed. Zoopagomycota comprises Entomophtoromycotina, Kickxellomycotina and Zoopagomycotina; it constitutes the earliest diverging lineage of zygomycetes and contains species th...