Intraspecific Variation of the Aquatic Fungus Articulospora tetracladia: An Ubiquitous Perspective

Abstract

The worldwide-distributed aquatic fungus Articulospora tetracladia Ingold is a dominant sporulating species in streams of the Northwest Iberian Peninsula. To elucidate the genetic diversity of A. tetracladia, we analyzed isolates collected from various types of plant litter or foam in streams from North and Central Portugal and North Spain, between 2000 and 2010. Genetic diversity of these fungal populations was assessed by denaturing gradient gel electrophoresis (DGGE) fingerprints and by using ITS1-5.8S-ITS2 barcodes. Moreover, ITS1-5.8S-ITS2 barcodes of A. tetracladia reported in other parts of the world (Central Europe, United Kingdom, Canada, Japan and Malaysia) were retrieved from the National Center for Biotechnology (NCBI) and the National Institute of Technology and Evaluation Biological Resource Center (NBRC) to probe into genetic diversity of A. tetracladia. PCR-DGGE of ITS2 region of 50 Iberian fungal isolates distinguished eight operational taxonomic units (OTUs), which were similar to those obtained from neighboring trees based on ITS2 gene sequences. On the other hand, ITS1-5.8S-ITS2 barcodes of 68 fungal isolates yielded nine OTUs, but five fungal isolates were not assigned to any of these OTUs. Molecular diversity was highest for OTU-8, which included only European isolates. Two haplotypes were observed within OTU-8 and OTU-9, while only one haplotype was found within each of the remaining OTUs. Malaysia did not share haplotypes with other countries. Overall results indicate that, apart from the Malaysian genotypes, A. tetracladia genotypes were geographically widespread irrespective of sampling time, sites or substrates. Furthermore, PCR-DGGE appeared to be a rapid tool for assessing intraspecific diversity of aquatic hyphomycetes.

Substantial compositional turnover of fungal communities in an alpine ridge‐to‐snowbed gradient

“…Articulospora is mainly known as aquatic hyphomycetes forming characteristic spores that spread through water (Quilliam & Jones ; Seena et al . ). Recent studies indicate that many such ‘Ingoldian fungi’ (Ingold ), including Articulospora, spend parts of their life cycle as plant root associates (Carlsen ; Selosse et al .…”

Biogeography of aquatic hyphomycetes: Current knowledge and future perspectives

“…Two studies using internal transcribed spacer region (ITS) barcodes from cosmopolitan species with isolates from different geographic regions, have somewhat contradictory conclusions Seena et al, 2012). Several ITS genotypes of A. tetracladia were geographically widespread (Iberian Peninsula, Central Europe, United Kingdom, Canada, and Japan) irrespective of sampling time, substratum or location , but Malaysian genotypes grouped in a different phylogenetic clade and were not shared by other countries .…”

Microscopy- or DNA-based analyses: Which methodology gives a truer picture of stream-dwelling decomposer fungal diversity?

“…PCR reactions of amplicons for DGGE analyses were done according to Seena et al (2012), using the primer pairs ITS3GC and ITS4 (White et al, 1990), which amplify the ITS2 region of fungal rRNA gene. DGGE analyses were performed using a DCode TM universal mutation detection system (Bio-Rad Laboratories, Hercules, CA, USA) according to Duarte et al (2010) with few modifications: gels had a denaturing gradient from 30 to 60% and were stained with 1x Midori Green (NIPPON Genetics EUROPE GmbH, Düren, Germany) for 10 min.…”