The origin story of land plants - the pivotal evolutionary event that paved the way for terrestrial ecosystems of today to flourish - lies within their closest living relatives: the streptophyte algae. Streptophyte cell wall composition has evolved such that profiles of cell wall polysaccharides can be used as taxonomic markers. Since xyloglucan is restricted to the streptophyte lineage, we hypothesized that fungal enzymes evolved in response to xyloglucan availability in streptophyte algal or land plant cell walls.
View Article and Find Full Text PDFLeaf-associated fungi, the fungi that depend on leaves to sporulate, have a rich Cenozoic record, however their earlier diversity is poorly characterized. Here we describe Harristroma eboracense gen. et sp.
View Article and Find Full Text PDFis a subsection composed of species of ectomycorrhizal fungi belonging to the hyperdiverse and cosmopolitan genus (Russulales). Species of are recognized by their fishy or shrimp odor, browning context, and a green reaction to iron sulfate. However, species delimitation has traditionally relied on morphology and analysis of limited molecular data.
View Article and Find Full Text PDFSome but not all of the species of 'little brown mushrooms' in the genus Galerina contain deadly amatoxins at concentrations equaling those in the death cap, Amanita phalloides. However, Galerina's ~300 species are notoriously difficult to identify by morphology, and the identity of toxin-containing specimens has not been verified with DNA barcode sequencing. This left open the question of which Galerina species contain toxins and which do not.
View Article and Find Full Text PDFPremise: Fossils can reveal long-vanished characters that inform inferences about the timing and patterns of diversification of living fungi. Through analyzing well-preserved fossil scutella, shield-like covers of fungal sporocarps, we describe a new taxon of early Dothideomycetes with a combination of characters unknown among extant taxa.
Methods: Macerated clays from the Potomac Group, lower Zone 1, from the Lower Cretaceous (Aptian, 125-113 Ma) of Virginia USA yielded one gymnospermous leaf cuticle colonized by 21 sporocarps of a single fungal morphotype.
Fungi have crucial roles in modern ecosystems as decomposers and pathogens, and they engage in various mutualistic associations with other organisms, especially plants. They have a lengthy geological history, and there is an emerging understanding of their impact on the evolution of Earth systems on a large scale. In this Review, we focus on the roles of fungi in the establishment and early evolution of land and freshwater ecosystems.
View Article and Find Full Text PDFFly-speck fungi reproduce via thyriothecia that consist of sporogenous tissue appressed to cuticle surfaces of plant leaves and covered by a shield-like scutellum. Thyriothecial scutella likely evolved repeatedly in Dothideomycetes (Ascomycota), and their morphology varies by lineage. Fly-speck fungi have an exceptionally good fossil record that begins in the Mesozoic.
View Article and Find Full Text PDFThe advantage of filamentous growth to the fungal lifestyle is so great that it arose multiple times. Most zoosporic fungi from phylum Chytridiomycota exhibit a monocentric thallus form consisting of anucleate filamentous rhizoids that anchor reproductive sporangia to substrata and absorb nutrients. Actin function during polarized growth and cytokinesis is well documented across eukaryotes, but its role in sculpting nonhyphal, nonyeast fungal cells is unknown.
View Article and Find Full Text PDFBackground: Septins are cytoskeletal proteins important in cell division and in establishing and maintaining cell polarity. Although septins are found in various eukaryotes, septin genes had the richest history of duplication and diversification in the animals, fungi and protists that comprise opisthokonts. Opisthokont septin paralogs encode modular proteins that assemble into heteropolymeric higher order structures.
View Article and Find Full Text PDFZoosporic fungi are key saprotrophs and parasites of plants, animals and other fungi, playing important roles in ecosystems. They comprise at least three phyla, of which two, Chytridiomycota and Blastocladiomycota, developed a range of thallus morphologies including branching hyphae. Here we describe gen.
View Article and Find Full Text PDFAnnu Rev Microbiol
September 2017
As decomposers or plant pathogens, fungi deploy invasive growth and powerful carbohydrate active enzymes to reduce multicellular plant tissues to humus and simple sugars. Fungi are perhaps also the most important mutualistic symbionts in modern ecosystems, transporting poorly soluble mineral nutrients to plants and thus enhancing the growth of vegetation. However, at their origin over a billion years ago, fungi, like plants and animals, were unicellular marine microbes.
View Article and Find Full Text PDFZygomycete 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.
View Article and Find Full Text PDFAs decomposers, fungi are key players in recycling plant material in global carbon cycles. We hypothesized that genomes of early diverging fungi may have inherited pectinases from an ancestral species that had been able to extract nutrients from pectin-containing land plants and their algal allies (Streptophytes). We aimed to infer, based on pectinase gene expansions and on the organismal phylogeny, the geological timing of the plant-fungus association.
View Article and Find Full Text PDFThe evolution of filamentous hyphae underlies an astounding diversity of fungal form and function. We studied the cellular structure and evolutionary origins of the filamentous form in the Monoblepharidomycetes (Chytridiomycota), an early-diverging fungal lineage that displays an exceptional range of body types, from crescent-shaped single cells to sprawling hyphae. To do so, we combined light and transmission electron microscopic analyses of hyphal cytoplasm with molecular phylogenetic reconstructions.
View Article and Find Full Text PDFSooty molds (Capnodiaceae) are saprotrophs on the surfaces of leaves, and they take their nutrients from honeydew exuded by sap-sucking insects. We describe and illustrate the sooty mold Fumiglobus pieridicola sp. nov.
View Article and Find Full Text PDFOn Vancouver Island, British Columbia, fertilization with nitrogen (N) and phosphorus (P) following clearcutting increases growth of western hemlock. To explore whether fertilization also resulted in ectomycorrhizal fungal communities that were more or less similar to neighboring unlogged stands, we sampled roots from western hemlock from three replicate plots from each of five different, well-characterized, forest stand types that differed in site type, and in logging and fertilization history. We harvested four samples of 100 ectomycorrhizal root tips from each plot, a total of 60 samples per stand type.
View Article and Find Full Text PDFOf the ancient clades of unicellular relatives of the multicellular animals, ichthyosporea are among the easiest to collect, cultivate, and analyze at the population level. Once identified, species can be correlated with their animal hosts and geographical ranges. However, the spherical stages common to many ichthyosporea provide little basis for morphological species identification.
View Article and Find Full Text PDFAnalyses of environmental DNAs have provided tantalizing evidence for "rozellida" or "cryptomycota", a clade of mostly undescribed and deeply diverging aquatic fungi. Here, we put cryptomycota into perspective through consideration of Rozella, the only clade member growing in culture. This is timely on account of the publication in Nature of the first images of uncultured cryptomycota from environmental filtrates, where molecular probes revealed non-motile cyst-like structures and motile spores, all lacking typical fungal chitinous cell walls.
View Article and Find Full Text PDFBackground: From a common ancestor with animals, the earliest fungi inherited flagellated zoospores for dispersal in water. Terrestrial fungi lost all flagellated stages and reproduce instead with nonmotile spores. Olpidium virulentus (= Olpidium brassicae), a unicellular fungus parasitizing vascular plant root cells, seemed anomalous.
View Article and Find Full Text PDFDuring a culture-based survey of opisthokonts living in marine invertebrate digestive tracts, we isolated two new eukaryotes that differed from described taxa by more than 10% in their small subunit ribosomal DNA sequences. Phylogenetic analysis showed that the two isolates represented a divergent clade of ichthyosporeans known previously only from environmental clone sequences. We used light and electron microscopy to describe the isolates as new genera and species Pirum gemmata and Abeoforma whisleri.
View Article and Find Full Text PDFWe use population genetics to detect the molecular footprint of a sexual cycle, of a haploid vegetative state, and of lack of host specificity in Pseudoperkinsus tapetis, a marine unicellular relative of the animals. Prior to this study, complete life cycles were not known for any of the unicellular lineages sharing common ancestry with multicellular animals and fungi. We established the first collection of conspecific cultures of any member from the unicellular opisthokont lineage ichthyosporea, isolating 126 cultures of P.
View Article and Find Full Text PDFStemphylium is a genus of plant pathogens and saprobes in the Pleosporaceae (Pleosporales, Dothideomycetes, Ascomycetes). The teleomorphs of Stemphylium, where known, are in Pleospora, with Pleospora herbarum as the type. The goal of this study was to present a rigorous phylogenetic analysis of the relationships among Stemphylium isolates with particular emphasis on species delimitation in the P.
View Article and Find Full Text PDFFertilization typically reduces ectomycorrhizal diversity shortly after its application but less is known about its longer-term influence on fungal species. Long-term effects are important in forests where fertilizer is rarely applied. We compared fungal species composition in western hemlock control plots with plots last fertilized 7 years ago with nitrogen (N) or nitrogen plus phosphorus (N + P).
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