Gerald L. Benny

A phylum-level phylogenetic classification of zygomycete fungi based on genome-scale data

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 that are primarily parasites and pathogens of small animals (e.g. amoeba, insects, etc.) and other fungi, i.e. mycoparasites. Mucoromycota comprises Glomeromycotina, Mortierellomycotina, and Mucoromycotina and is sister to Dikarya. It is the more derived clade of zygomycetes and mainly consists of mycorrhizal fungi, root endophytes, and decomposers of plant material. Evolution of trophic modes, morphology, and analysis of genome-scale data are discussed.

Phylogenetic relationships among the Harpellales and Kickxellales

DNA sequences of the nuclear encoded small subunit (SSU) 18S ribosomal RNA gene and characters from a morphological/physiological dataset were analyzed by maximum parsimony to investigate phylogene...

OBSERVATIONS ON THAMNIDIACEAE (MUCORALES). V. THAMNIDIUM

The genus Thamnidium is restricted to a single taxon T. elegans that produces deliquescent-walled sporangia at the apex of a primary sporophore or its branches along with persistent-walled sporangiola on lateral dichotomous branchlets. In some instances only sporangia or sporangiola may be formed on a given sporophore. The dichotomous branchlets may arise singly, in pairs, or in verticels of three or more. The species is illustrated with photographs and line drawings. Thamnidium verticellatum is regarded as a synonym of T. elegans. An extensive list of synonyms is supplied.

Lobosporangium, a new name for Echinosporangium Malloch, and Gamsiella ,a new genus for Mortierella multidivaricata

Lobosporangium is proposed as a new name for Echinosporangium Malloch, a later homonym of Echinosporangium Kylin. Lobosporangium transversale was isolated from arid soils on three occasions between 1964 and 1968 but has not been reported again. Observations on sporangium development in culture revealed rapid sporangiospore germination, rapidly growing hyphae forming anastomoses, threefold dichotomously branching aerial sporangiophores and formation of clusters of eight sporangia. The sporangia of L. transversale are illustrated, and the placement of Lobosporangium in the Mortierellaceae is discussed. A new genus, Gamsiella, is proposed that is based on Mortierella multidivaricata. Sporangial ontogeny of Gamsiella is compared with that presented here for Lobosporangium.

Ultrastructural studies of the spore wall of Gigaspora albida (Glomales)

Morphological and ultrastructural studies were carried out to describe spore wall structure in Gigaspora albida. Spores at different stages of development were observed, with different wall pattern...

Phylogenetic analysis of the genus Modicella reveals an independent evolutionary origin of sporocarp-forming fungi in the Mortierellales.

Most studies of tissue differentiation and development have focused on animals and plants but many fungi form multi-cellular aggregations of spore-bearing tissue known as fruiting bodies or sporocarps. The ability to form sporocarps has arisen independently in several different evolutionary lineages of fungi. Evolutionary relationships of most sporocarp-forming fungi are well known, but the enigmatic zygomycete genus Modicella contains two species of sporocarp-forming fungi for which the phylogenetic affinities have not been explored based on molecular data. Species of Modicella have an uncertain trophic mode and have alternatively been considered members of the order Endogonales (which contains documented species of sporocarp-forming fungi) or the order Mortierellales (which contains no previously documented species of sporocarp-forming fungi). In this study we perform phylogenetic analyses based on ribosomal DNA of Modicella malleola from the Northern Hemisphere and Modicella reniformis from the Southern Hemisphere to determine the evolutionary affinities of the genus Modicella. Our analyses indicate that Modicella is a monophyletic genus of sporocarp-forming fungi nested within the Mortierellales, a group of microfungi with no previously documented sporocarp-forming species. Because Modicella is distantly related to all other known sporocarp-forming fungi, we infer that this lineage has independently evolved the ability form sporocarps. We conclude that the genus Modicella should be a high priority for comparative genomics studies to further elucidate the process of sporocarp formation in fungi.

A second species of Chaetomidium with a cephalothecoid peridium wall

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Gilbertellaceae, a new family of the Mucorales (Zygomycetes)

The Gilbertellaceae Benny (Mucorales) is proposed for a single genus, Gilbertella, characterized by producing sporangia with a persistent wall dehiscing via a longitudinal suture, sporangiospores with apical, hyaline appendages, and Mucor-type zygospores. The relationship of Gilbertellaceae to Choanephoraceae and other families of the Mucorales, and Zygomycetes, is discussed.

8 Zygomycetous Fungi: Phylum Entomophthoromycota and Subphyla Kickxellomycotina, Mortierellomycotina, Mucoromycotina, and Zoopagomycotina

In this chapter, the zygomycotan fungi are discussed and some information is provided on their occurrence, distribution, and economic importance. The role of these fungi in food spoilage, as plant pathogens, in zygomycosis, and industry (biotechnology, biodegradation, biosorption, bioremediation, biotransformation), is discussed, as are endobacteria and toxins, light, physiology, and mating. The asexual and sexual reproductive structures are briefly discussed, including the difference between conidia and unispored sporangiola.

Observations on Thamnidiaceae (Mucorales). VI: Two new species of Dichotomocladium and the zygospores of D. hesseltinei (Chaetocladiaceae)

Two new species are described in Dichotomocladium. One species with globose sporangiola, D. sphaerosporum, was isolated from dung collected in Mianwali, Pakistan, and is similar to D. elegans in its general habit. The second species with obovoid sporangiola, D. floridanum, was isolated from dung collected in Gainesville, Florida, and resembles D. robustum. The zygospores of D. hesseltinei have hemispherical suspensors and are described for the first time. Chaetocladiaceae is revived for fungi having branched (dichotomous, verticillate) fertile hyphae, pedicellate, unispored sporangiola which are produced on fertile vesicles, and sterile spines. Dichoto? mocladium is transferred to Chaetocladiaceae, which contains only one other genus, Chaetocladium. Chaetocladium and Dichotomocladium each are considered monophyletic, and together comprise the monophyletic Chaetocladiaceae. Keys are provided to the genera of Chaetocladiaceae and the species of Dichotomocladium. A list of families and genera currently included in Mucorales also is provided.