Published in Proceedings of the Royal Society B
Molecular diversity and distribution of marine fungi across 130 European environmental samples
Thomas A. Richards, Guy Leonard, Frédéric Mahé, Javier del Campo, Sarah Romac, Meredith D. M. Jones, Finlay Maguire, Micah Dunthorn, Colomban De Vargas, Ramon Massana, Aurélie Chambouvet
Environmental DNA and culture-based analyses have suggested that fungi are present in low diversity and in low abundance in many marine environments, especially in the upper water column. Here, we use a dual approach involving high-throughput diversity tag sequencing from both DNA and RNA templates and fluorescent cell counts to evaluate the diversity and relative abundance of fungi across marine samples taken from six European near-shore sites. We removed very rare fungal operational taxonomic units (OTUs) selecting only OTUs recovered from multiple samples for a detailed analysis. This approach identified a set of 71 fungal ‘OTU clusters’ that account for 66% of all the sequences assigned to the Fungi. Phylogenetic analyses demonstrated that this diversity includes a significant number of chytrid-like lineages that had not been previously described, indicating that the marine environment encompasses a number of zoosporic fungi that are new to taxonomic inventories. Using the sequence datasets, we identified cases where fungal OTUs were sampled across multiple geographical sites and between different sampling depths. This was especially clear in one relatively abundant and diverse phylogroup tentatively named Novel Chytrid-Like-Clade 1 (NCLC1). For comparison, a subset of the water column samples was also investigated using fluorescent microscopy to examine the abundance of eukaryotes with chitin cell walls. Comparisons of relative abundance of RNA-derived fungal tag sequences and chitin cell-wall counts demonstrate that fungi constitute a low fraction of the eukaryotic community in these water column samples. Taken together, these results demonstrate the phylogenetic position and environmental distribution of 71 lineages, improving our understanding of the diversity and abundance of fungi in marine environments.
Gordon Research Seminar on Marine Microbes
Chairs: Javier del Campo & Bryndan Durham
June 18-19, 2016
PGA Catalunya Business and Convention Centre
The Gordon Research Seminar on Marine Microbes is a unique forum for graduate students, post-docs, and other scientists with comparable levels of experience and education to present and exchange new data and cutting edge ideas.
Marine microorganisms interact constantly among themselves and with other members of the trophic network. These interactions define their evolutionary fate and underlie the biogeochemical fluxes that will drive ecological processes in current and future oceans. The seminar will bring together microbial ecologists and evolutionary biologists to discuss and debate about where, when and why marine microbes interact, who are the main players mediating these processes, and what will be the resulting evolutionary and ecological outputs.
Applications for this meeting must be submitted by May 21, 2016. Please apply early, as some meetings become oversubscribed (full) before this deadline. Note: Applications for oversubscribed meetings will only be considered by the Conference Chair if more seats become available due to cancellations.
Published in Current Biology
Phylogenomics Reveals Convergent Evolution of Lifestyles in Close Relatives of Animals and Fungi
Guifré Torruella, Alex de Mendoza, Xavier Grau-Bové, Meritxell Antó, Mark A. Chaplin, Javier del Campo, Laura Eme, Gregorio Pérez-Cordón, Christopher M. Whipps, Krista M. Nichols, Richard Paley, Andrew J. Roger, Ariadna Sitjà-Bobadilla, Stuart Donachie, Iñaki Ruiz-Trillo
The Opisthokonta are a eukaryotic supergroup divided in two main lineages: animals and related protistan taxa, and fungi and their allies [1 and 2]. There is a great diversity of lifestyles and morphologies among unicellular opisthokonts, from free-living phagotrophic flagellated bacterivores and filopodiated amoebas to cell-walled osmotrophic parasites and saprotrophs. However, these characteristics do not group into monophyletic assemblages, suggesting rampant convergent evolution within Opisthokonta. To test this hypothesis, we assembled a new phylogenomic dataset via sequencing 12 new strains of protists. Phylogenetic relationships among opisthokonts revealed independent origins of filopodiated amoebas in two lineages, one related to fungi and the other to animals. Moreover, we observed that specialized osmotrophic lifestyles evolved independently in fungi and protistan relatives of animals, indicating convergent evolution. We therefore analyzed the evolution of two key fungal characters in Opisthokonta, the flagellum and chitin synthases. Comparative analyses of the flagellar toolkit showed a previously unnoticed flagellar apparatus in two close relatives of animals, the filasterean Ministeria vibrans and Corallochytrium limacisporum. This implies that at least four different opisthokont lineages secondarily underwent flagellar simplification. Analysis of the evolutionary history of chitin synthases revealed significant expansions in both animals and fungi, and also in the Ichthyosporea and C. limacisporum, a group of cell-walled animal relatives. This indicates that the last opisthokont common ancestor had a complex toolkit of chitin synthases that was differentially retained in extant lineages. Thus, our data provide evidence for convergent evolution of specialized lifestyles in close relatives of animals and fungi from a generalist ancestor.