Detection and Identification of Fungi Intimately Associated with the Brown SeaweedFucus serratus

Abstract

The filamentous fungi associated with healthy and decaying Fucus serratus thalli were studied over a 1-year period using isolation methods and molecular techniques such as 28S rRNA gene PCR-denaturing gradient gel electrophoresis (DGGE) and phylogenetic and real-time PCR analyses. The predominant DGGE bands obtained from healthy algal thalli belonged to the Lindra, Lulworthia, Engyodontium, Sigmoidea/Corollospora complex, and Emericellopsis/Acremonium-like ribotypes. In the culture-based analysis the incidence of recovery was highest for Sigmoidea marina isolates. In general, the environmental sequences retrieved could be matched unambiguously to isolates recovered from the seaweed except for the Emericellopsis/Acremonium-like ribotype, which showed 99% homology with the sequences of four different isolates, including that of Acremonium fuci. To estimate the extent of colonization of A. fuci, we used a TaqMan real-time quantitative PCR assay for intron 3 of the beta-tubulin gene, the probe for which proved to be species specific even when it was used in amplifications with high background concentrations of other eukaryotic DNAs. The A. fuci sequence was detected with both healthy and decaying thalli, but the signal was stronger for the latter. Additional sequence types, representing members from the Dothideomycetes, were recovered from the decaying thallus DNA, which suggested that a change in fungal community structure had occurred. Phylogenetic analysis of these environmental sequences and the sequences of isolates and type species indicated that the environmental sequences were novel in the Dothideomycetes.Coastal macrophytes are part of highly productive ecosystems and have essential functions in nutrient cycling and habitat structuring (8,30). Helgoland intertidal marine seaweed populations are dominated by fucoids with diverse associated biocenoses. The complex communities that develop in these systems provide models for investigating algafungus interactions in a natural environment. Pathogens and parasites are the predominant fungi in seaweed communities that have been described (47); however, most of these organisms cannot be cultured in the laboratory and are known only from herbarium specimens (26, 39). Other algicolous fungi include saprobes and mycobionts, and there is little information on the autecology of these organisms. Studies of the interactions between these fungi and their algal hosts, therefore, can be effectively undertaken only by using a molecular approach to detect and differentiate between environmental signal sequences.In a preliminary study of fungi associated with Fucus serratus, Zuccaro et al. (48) developed and described a PCRdenaturing gradient gel electrophoresis (DGGE) system, using novel fungus-specific primers that amplified the second domain (D2) of the nuclear large rRNA region. Fungal sequences retrieved from algal tissue matched sequences from ascomycetous groups known to be active in marine environments, as well as sequences from a group of isolates belonging to the genu...

Diversity and bioprospecting of fungal communities associated with endemic and cold-adapted macroalgae in Antarctica

“…However, limited attention has thus far been devoted to the fungal diversity of the Antarctic marine environment. Few existing studies address marine Antarctic Lobophora, Padina, Porphyra, Portieria, Saccorhiza, Sargassum, Stoechospermum, Turbinaria and Ulva Volkmann-Kohlmeyer, 1991, Stanley, 1992;Zuccaro and Mitchell, 2005;Zuccaro et al, 2008;Suryanarayanan et al, 2010). To the best of our knowledge, except for an initial contribution by Loque et al (2010), no other data are available regarding the species composition of fungal communities associated with Antarctic macroalgae.…”

Mycochemistry of marine algicolous fungi

“…Although Chytridiomycota, Zygomycota, and Basidiomycota (Porter and Farnham 1986) have been encountered, they are much less than Ascomycota and anamorphic taxa. A few facultative marine fungi, such as Aspergillus terreus and A. niger, without host specificity tend to dominate the fungal community, but obligate ones may replace their position in some algae (Zuccaro et al 2003(Zuccaro et al , 2008. It is difficult to give an unambiguous conclusion based on the limited data, because the occurrence of MAFs varies with their adaptation and antagonism.…”

“…Among them, obligate marine fungi, such as Lindra sp., Lulworthia sp., and Corollospora sp. occurred in low frequency (Zuccaro et al 2003(Zuccaro et al , 2008. As opposed, facultative marine fungi of the genera Aspergillus, Alternaria, Chaetomium, Cladosporium, Fusarium, Paecilomyces, and Penicillium were commonly encountered, which could colonize taxonomically disparate algae.…”

“…Most of these fungi have been recognized from Phaeophyta and Rhodophyta, and some feature high specificity for their algal hosts Jones et al 2009). Especially, several of them are even obligate parasites, such as Spathulospora spp., Didymella fucicola, and Phycomelaina laminariae (Schatz 1984;Nakagiri and Ito 1997;Zuccaro et al 2008), and obligate symbionts (mycophycobioses), such as Mycophycias ascophylli and Blodgettia confervoides (Xu et al 2008a;Jones et al 2009). …”

Fungal Community Structure of Macroalga Ulva Intestinalis Revealed by Miseq Sequencing

“…The results showed that culture dependent technique only revealed less than 1% of fungal community (Handelsman, 2005). Other methods which have been used to study fungal community were Amplified Ribosomal DNA Restriction Analysis (Menezes et al, 2010) and PCR-denaturing gradient gel electrophoresis (DGGE) (Zuccaro et al, 2008). Unfortunately, those traditional culture independent techniques were thought to only recover a small proportion of community in the environmental samples (Fu, Lv, & Chen, 2016;O'Brien, Parrent, Jackson, Moncalvo, & Vilgalys, 2005).…”