Some new DNA barcodes of aquatic hyphomycete species

Aquatic hyphomycetes play a key role in organic matter processing in freshwaters. Traditionally, species have been identified through the morphology of their conidia, but mycelia can fail to sporulate, making aquatic hyphomycetes a group where DNA barcoding is crucial. We generated ITS barcodes for nine aquatic hyphomycetes without published ITS sequences that, together with all published sequences, were used to construct a neighbor-joining tree. In general, the new barcoded species grouped with species of the same genus, but Tricladium and Triscelophorus species were interspersed among different clades of the tree, confirming the multiple origins of aquatic hyphomycetes.Fundo Europeu de Desenvolvimento Regional through COMPETE (FCOMP-01-0124-FEDER-013954)Fundação para a Ciência e a Tecnologia - FCT (PEst-OE/BIA/UI4050/2014, PTDC/AAC-AMB/113746/2009 and BPD/47574/2008

Effects of aquatic hyphomycete species richness and identity on leaf mass loss, fungal biomass and conidium production

Resumo da comunicação apresentada no "IX International Marine and Freshwater Mycology Symposium", Chiang Mai, Tailândia, 14 a 19 Novembro 2004.Biodiversity is rapidly declining as a consequence of several human activities, leading to an increased interest in determining how species loss affects ecosystem functioning. The relationship between biodiversity and ecosystem processes has been widely documented in terrestrial systems. Comparatively few studies have been conducted in aquatic systems. Aquatic hyphomycetes, an ecological group of fungi that play a key role in leaf litter decomposition in streams, were used to investigate how species loss might affect decomposition processes. The effects of species richness and species identity on leaf mass loss, fungal biomass and conidium production were tested in microcosms. Alder leaf disks were inoculated with combinations of one to four aquatic hyphomycete species (Articulospora tetracladia, Flagellospora curta, Geniculospora grandis and Heliscus submersus) and continuously aerated under artificial light for 27 days. Both species richness and identity significantly affected fungal biomass and total conidium production (as numbers or biomass of conidia), whereas only species identity had a significant effect on leaf mass losses. In mixed cultures, leaf mass losses, fungal biomass and conidium production were greater than expected from the sum of the contribution of each species in monocultures.Fundação para a Ciência e a Tecnologia (FCT) - POCTI/34024/BSE/2000, SFRH/BD/13482/2003

A decade's perspective on the impact of DNA sequencing on aquatic hyphomycete research

A decade has passed since the first DNA sequences of aquatic hyphomycete species have become available. They have illuminated aspects of their phylogeny and evolution that were inaccessible by conventional methods. Here we present examples of how the resulting information has modified our knowledge of aquatic hyphomycetes. Generating more and better DNA sequence data will continue to expand the range of questions we can investigate concerning the evolution and ecology of aquatic hyphomycetes. We highlight the importance of moving forward with next generation sequencing technologies to more accurately determine the true diversity and composition of fungal communities on environmental samples. In addition, sequences targeting functional genes will offer further insights into the roles of aquatic fungi in ecosystem processes.The European Regional Development Fund - Operational Competitiveness Programme (FEDER-POFC-COMPETE) and the Portuguese Foundation for Science and Technology supported this study (PEst-C/BIA/UI4050/2011 and PTDC/AACAMB/113746/2009) and S. Duarte (SFRH/BPD/47574/2008

Preliminary insights into the phylogeography of six aquatic Hyphomycete Species

Aquatic hyphomycetes occur worldwide on a wide range of plant substrates decomposing in freshwaters, and are known to play a key role in organic matter turnover. The presumed worldwide distribution of many aquatic hyphomycete species has been based on morphology-based taxonomy and identification, which may overlook cryptic species, and mask global-scale biogeographical patterns. This might be circumvented by using DNA sequence data. The internal transcribed spacer (ITS) region from rDNA was recently designated as the most suitable barcode for fungal identification. In this study, we generated ITS barcodes of 130 isolates belonging to 6 aquatic hyphomycete species (Anguillospora filiformis, Flagellospora penicillioides, Geniculospora grandis, Lunulospora curvula, Tetrachaetum elegans and Tricladium chaetocladium), and collected from streams of Southwest Europe (86 isolates) and East Australia (44 isolates). European and Australian populations of 4 species (A. filiformis, F. penicillioides, G. grandis and T. elegans) grouped into different clades, and molecular diversity indices supported significant differentiation. Continents did not share haplotypes, except for T. chaetocladium. Overall results show substantial population diversity for all tested species and suggests that the biogeography of aquatic hyphomycetes may be species-specific.The European Regional Development Fund - Operational Competitiveness Programme (FEDER-POFC-COMPETE) (PEst-C/BIA/UI4050/2011 and PTDC/AAC-AMB/113746/2009) and SD (SFRH/BPD/47574/2008). The Natural Sciences and Engineering Research Council of Canada (NSERC) also supported this study and FB.Fundação para a Ciência e a Tecnologia (FCT) - PEst-C/BIA/UI4050/2011, PTDC/AAC-AMB/113746/2009, SFRH/BPD/47574/200

Biogeography of aquatic fungi: preliminary conclusions

FEDER-POFC-COMPETE and FCT supported this study (PEst-C/BIA/UI4050/2011 and PTDC/AAC-AMB/113746/2009) and SD (SFRH/BPD/47574/2008).Fundação para a Ciência e a Tecnologia (FCT) - PEst-C/BIA/UI4050/2011, PTDC/AAC-AMB/113746/2009, /BPD/47574/200

Taxa-area relationship of aquatic fungi on deciduous leaves

One of the fundamental patterns in macroecology is the increase in the number of observed taxa with size of sampled area. For microbes, the shape of this relationship remains less clear. The current study assessed the diversity of aquatic fungi, by the traditional approach based on conidial morphology (captures reproducing aquatic hyphomycetes) and next generation sequencing (NGS; captures other fungi as well), on graded sizes of alder leaves (0.6 to 13.6 cm2). Leaves were submerged in two streams in geographically distant locations: the Oliveira Stream in Portugal and the Boss Brook in Canada. Decay rates of alder leaves and fungal sporulation rates did not differ between streams. Fungal biomass was higher in Boss Brook than in Oliveira Stream, and in both streams almost 100% of the reads belonged to active fungal taxa. In general, larger leaf areas tended to harbour more fungi, but these findings were not consistent between techniques. Morphospecies-based diversity increased with leaf area in Boss Brook, but not in Oliveira Stream; metabarcoding data showed an opposite trend. The higher resolution of metabarcoding resulted in steeper taxa-accumulation curves than morphospecies-based assessments (fungal conidia morphology). Fungal communities assessed by metabarcoding were spatially structured by leaf area in both streams. Metabarcoding promises greater resolution to assess biodiversity patterns in aquatic fungi and may be more accurate for assessing taxa-area relationships and local to global diversity ratios.This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569), funded by national funds through the Portuguese Foundation for Science and Technology (FCT) I.P. (http://www.fct.pt/) and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI) and by the project PTDC/AAC-AMB/117068/2010, funded by national funds through FCT I.P. and the European Regional Development Funds through the Operational Competitiveness Program (FEDER-COMPETE). Support from FCT to SD (SFRH/BPD/47574/2008 and SFRH/BPD/109842/2015) and from NSERC Discovery grant program (http://www.nserc-crsng.gc.ca/index_eng.asp) to FB is also acknowledged. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.info:eu-repo/semantics/publishedVersio

Beyond the water column: aquatic hyphomycetes outside their preferred habitat

Aquatic hyphomycetes have adapted to running waters by their uncommon conidial shape, which facilitates dispersal as well as adherence to plant substrata. However, they have been early and regularly reported to occur in a variety of environments other than their preferred habitat (e.g., in lentic freshwaters, brackish and marine environments, in terrestrial niches such as stream banks, dew, canopy waters and tree holes). In addition, several aquatic hyphomycetes have adapted to a mutualistic lifestyle which may involve plant defence, as endophytes in leaves, gymnosperm needles, orchids and terrestrial roots. There are several lines of evidence suggesting that aquatic hyphomycetes survive under terrestrial conditions due to their sexual states. Although exhibiting higher diversity in pristine streams, aquatic hyphomycetes can survive environmental stress, e.g., pollution or river intermittency. They also inhabit ground and hyporheic waters, where they appear to be subjected to both physical and physiological selection. Appropriate methods including molecular ones should provide a more comprehensive view of the occurrence and ecological roles of aquatic hyphomycetes outside their preferred habitat

Rapid characterization of aquatic hyphomycetes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Protein fingerprinting using matrix-assisted laser desorption/ionization time-of-flight mass spec-trometry (MALDI-TOF MS) is a rapid, reliable, and economical method to characterize isolates of terrestrial fungi and other microorganisms. The objective of our study was to evaluate the suitability of MALDI-TOF MS for the identification of aquatic hyphomycetes, a polyphyletic group of fungi that play crucial roles in stream ecosystems. To this end, we used 34 isolates of 21 aquatic hyphomycete species whose identity was confirmed by spore morphology and internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) nuc rDNA sequencing. We tested the efficiency of three protein extraction methods, including chemical and mechanical treatments using 13 different protocols, with the objective of producing high-quality MALDI-TOF mass spectra. In addition to extraction protocols, mycelium age was identified as a key parameter affecting protein extraction efficiency. The dendrogram based on mass-spectrum similarity indicated good and relevant taxonomic discrimination; the tree structure was comparable to that of the phylogram based on ITS sequences. Consequently, MALDI-TOF MS could reliably identify the isolates studied and provided greater taxonomic accuracy than classical morphological methods. MALDI-TOF MS seems suited for rapid characterization and identification of aquatic hyphomycete species

Biodiversity of leaf litter fungi in streams along a latitudinal gradient

Global patterns of biodiversity have emerged for soil microorganisms, plants and animals, and the extraordinary significance of microbial functions in ecosystems is also well established. Virtually unknown, however, are large- scale patterns of microbial diversity in freshwaters, although these aquatic ecosystems are hotspots of biodiversity and biogeochemical processes. Here we report on the first large-scale study of biodiversity of leaf-litter fungi in streams along a latitudinal gradient unravelled by Illumina sequencing. The study is based on fungal commu- nities colonizing standardized plant litter in 19 globally distributed stream locations between 69°N and 44°S. Fungal richness suggests a hump-shaped distribution along the latitudinal gradient. Strikingly, community com- position of fungi was more clearly related to thermal preferences than to biogeography. Our results suggest that identifying differences in key environmental drivers, such as temperature, among taxa and ecosystem types is critical to unravel the global patterns of aquatic fungal diversity