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Author

Joseph B. Morton

Other affiliations: Arizona State University
Bio: Joseph B. Morton is an academic researcher from West Virginia University. The author has contributed to research in topics: Glomus & Mycorrhiza. The author has an hindex of 25, co-authored 27 publications receiving 6666 citations. Previous affiliations of Joseph B. Morton include Arizona State University.

Papers
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Journal ArticleDOI
19 Oct 2006-Nature
TL;DR: It is indicated that there may have been at least four independent losses of the flagellum in the kingdom Fungi, and the enigmatic microsporidia seem to be derived from an endoparasitic chytrid ancestor similar to Rozella allomycis, on the earliest diverging branch of the fungal phylogenetic tree.
Abstract: The ancestors of fungi are believed to be simple aquatic forms with flagellated spores, similar to members of the extant phylum Chytridiomycota (chytrids). Current classifications assume that chytrids form an early-diverging clade within the kingdom Fungi and imply a single loss of the spore flagellum, leading to the diversification of terrestrial fungi. Here we develop phylogenetic hypotheses for Fungi using data from six gene regions and nearly 200 species. Our results indicate that there may have been at least four independent losses of the flagellum in the kingdom Fungi. These losses of swimming spores coincided with the evolution of new mechanisms of spore dispersal, such as aerial dispersal in mycelial groups and polar tube eversion in the microsporidia (unicellular forms that lack mitochondria). The enigmatic microsporidia seem to be derived from an endoparasitic chytrid ancestor similar to Rozella allomycis, on the earliest diverging branch of the fungal phylogenetic tree.

1,682 citations

Journal ArticleDOI
TL;DR: Spore counts in field soil and estimates from sorghum trap cultures showed that the association of AM fungi with particular host plants in the field was positively correlated with the sporulation rates observed on those hosts in the microcosm experiments, suggesting host-dependent differences in fungal growth rates.
Abstract: 1 In laboratory microcosm experiments, co-occurring plant species were found to support very different rates of sporulation of arbuscular mycorrhizal (AM) fungi. These differences were not affected by the time of harvest, suggesting that they reflect host-dependent differences in fungal growth rates, rather than host-dependent timing of sporulation. 2 Spore counts in field soil and estimates from sorghum trap cultures showed that the association of AM fungi with particular host plants in the field was positively correlated with the sporulation rates observed on those hosts in the microcosm experiments. 3 The AM fungal species richness observed at the field site was high relative to estimates made in previous studies. 23 distinct species of AM fungi were found, seven of which have not been previously described. 4 The host-dependence of the relative growth rates of fungal populations may play an important role in the maintenance of fungal species diversity.

585 citations

Journal ArticleDOI
TL;DR: This study is the outcome, wherein the classification of Glomeromycota is revised by rejecting some new names on the grounds that they are founded in error and by synonymizing others that, while validly published, are not evidence-based.
Abstract: The publication of a large number of taxon names at all levels within the arbuscular mycorrhizal fungi (Glomeromycota) has resulted in conflicting systematic schemes and generated considerable confusion among biologists working with these important plant symbionts. A group of biologists with more than a century of collective experience in the systematics of Glomeromycota examined all available molecular–phylogenetic evidence within the framework of phylogenetic hypotheses, incorporating morphological characters when they were congruent. This study is the outcome, wherein the classification of Glomeromycota is revised by rejecting some new names on the grounds that they are founded in error and by synonymizing others that, while validly published, are not evidence-based. The proposed “consensus” will provide a framework for additional original research aimed at clarifying the evolutionary history of this important group of symbiotic fungi.

508 citations

Journal ArticleDOI
TL;DR: Research on the ecology of interactions between plants and arbuscular mycorrhizal fungi and the importance of AM fungi in the facilitation of plants' uptake of phosphorus is presented.
Abstract: Presents research on the ecology of interactions between plants and arbuscular mycorrhizal (AM) fungi. Discovery that the underground world is diverse and dynamic; Process of discovery; Mechanisms that might maintain fungal diversity; Implications of this diversity for ecology as a whole; Importance of AM fungi in the facilitation of plants' uptake of phosphorus.

408 citations


Cited by
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Journal ArticleDOI
TL;DR: Among the regions of the ribosomal cistron, the internal transcribed spacer (ITS) region has the highest probability of successful identification for the broadest range of fungi, with the most clearly defined barcode gap between inter- and intraspecific variation.
Abstract: Six DNA regions were evaluated as potential DNA barcodes for Fungi, the second largest kingdom of eukaryotic life, by a multinational, multilaboratory consortium. The region of the mitochondrial cytochrome c oxidase subunit 1 used as the animal barcode was excluded as a potential marker, because it is difficult to amplify in fungi, often includes large introns, and can be insufficiently variable. Three subunits from the nuclear ribosomal RNA cistron were compared together with regions of three representative protein-coding genes (largest subunit of RNA polymerase II, second largest subunit of RNA polymerase II, and minichromosome maintenance protein). Although the protein-coding gene regions often had a higher percent of correct identification compared with ribosomal markers, low PCR amplification and sequencing success eliminated them as candidates for a universal fungal barcode. Among the regions of the ribosomal cistron, the internal transcribed spacer (ITS) region has the highest probability of successful identification for the broadest range of fungi, with the most clearly defined barcode gap between inter- and intraspecific variation. The nuclear ribosomal large subunit, a popular phylogenetic marker in certain groups, had superior species resolution in some taxonomic groups, such as the early diverging lineages and the ascomycete yeasts, but was otherwise slightly inferior to the ITS. The nuclear ribosomal small subunit has poor species-level resolution in fungi. ITS will be formally proposed for adoption as the primary fungal barcode marker to the Consortium for the Barcode of Life, with the possibility that supplementary barcodes may be developed for particular narrowly circumscribed taxonomic groups.

4,116 citations

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TL;DR: An enhanced understanding of the skin microbiome is necessary to gain insight into microbial involvement in human skin disorders and to enable novel promicrobial and antimicrobial therapeutic approaches for their treatment.
Abstract: The skin is the human body's largest organ, colonized by a diverse milieu of microorganisms, most of which are harmless or even beneficial to their host. Colonization is driven by the ecology of the skin surface, which is highly variable depending on topographical location, endogenous host factors and exogenous environmental factors. The cutaneous innate and adaptive immune responses can modulate the skin microbiota, but the microbiota also functions in educating the immune system. The development of molecular methods to identify microorganisms has led to an emerging view of the resident skin bacteria as highly diverse and variable. An enhanced understanding of the skin microbiome is necessary to gain insight into microbial involvement in human skin disorders and to enable novel promicrobial and antimicrobial therapeutic approaches for their treatment.

2,279 citations

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TL;DR: It is shown that NC-endophytes represent three distinct functional groups based on host colonization and transmission, in planta biodiversity and fitness benefits conferred to hosts, and key questions for future work in endophyte biology are highlighted.
Abstract: Summary 1 Summary All plants in natural ecosystems appear to be symbiotic with fungal endophytes. This highly diverse group of fungi can have profound impacts on plant communities through increasing fitness by conferring abiotic and biotic stress tolerance, increasing biomass and decreasing water consumption, or decreasing fitness by altering resource allocation. Despite more than 100 yr of research resulting in thousands of journal articles, the ecological significance of these fungi remains poorly characterized. Historically, two endophytic groups (clavicipitaceous (C) and nonclavicipitaceous (NC)) have been discriminated based on phylogeny and life history traits. Here, we show that NC-endophytes represent three distinct functional groups based on host colonization and transmission, in planta biodiversity and fitness benefits conferred to hosts. Using this framework, we contrast the life histories, interactions with hosts and potential roles in plant ecophysiology of C- and NC-endophytes, and highlight several key questions for future work in endophyte biology.

2,278 citations

Journal ArticleDOI
TL;DR: A comprehensive phylogenetic classification of the kingdom Fungi is proposed, with reference to recent molecular phylogenetic analyses, and with input from diverse members of the fungal taxonomic community.

2,096 citations

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TL;DR: Vesicular-arbuscular mycorrhizal fungi can affect the water balance of both amply watered and droughted host plants and the influence of soil drying on the fungi is discussed.
Abstract: Vesicular-arbuscular mycorrhizal fungi can affect the water balance of both amply watered and droughted host plants. This review summarizes these effects and possible causal mechanisms. Also discussed are host drought resistance and the influence of soil drying on the fungi.

1,964 citations