New Dothideomycetes from Freshwater Habitats in Spain.

Viridiana Magaña-Dueñas,Alberto Miguel Stchigel,José Francisco Cano-Lira

doi:10.3390/jof7121102

Viridiana Magaña-Dueñas, Alberto Miguel Stchigel + Show 1 more

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https://doi.org/10.3390/jof7121102

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Abstract

The Dothideomycetes are a class of cosmopolitan fungi that are present principally in terrestrial environments, but which have also been found in freshwater and marine habitats. In the present study, more than a hundred samples of plant debris were collected from various freshwater locations in Spain. Its incubation in wet chambers allowed us to detect and to isolate in pure culture numerous fungi producing asexual reproductive fruiting bodies (conidiomata). Thanks to a morphological comparison and to a phylogenetic analysis that combined the internal transcribed spacer (ITS) region of the nrDNA with fragments of the RNA polymerase II subunit 2 (rpb2), beta tubulin (tub2), and the translation elongation factor 1-alpha (tef-1) genes, six of those strains were identified as new species to science. Three belong to the family Didymellaceae: Didymella brevipilosa, Heterophoma polypusiformis and Paraboeremia clausa; and three belong to the family Phaeosphaeriaceae: Paraphoma aquatica, Phaeosphaeria fructigena and Xenophoma microspora. The finding of these new taxa significantly increases the number of the coelomycetous fungi that have been described from freshwater habitats.

Highlights

Freshwater fungi are a taxonomically heterogeneous ecological group of organisms of cosmopolitan distribution playing an important ecological role in the recycling of dead organic matter [1], where some of them are restricted to tropical or temperate areas, and others are present in cold-water habitats [2] Most freshwater fungi belong to the phylum Ascomycota, whose biodiversity depends on their geographical location and substrates [3]
Molecular biology helped to clarify the phylogenetic relationships between the members of the Dothideomycetes, especially among several phoma-like fungal taxa
Multilocus analyses based on LSU, internal transcribed spacer (ITS), rpb2, tef-1, and tub2 sequences have been widely used to define the species boundaries for the Didymellaceae, the Phaeosphaeriaceae and other families of the Dothideomycetes [23,24,27,28,29,30]

Summary

Introduction

Freshwater fungi are a taxonomically heterogeneous ecological group of organisms of cosmopolitan distribution playing an important ecological role in the recycling of dead organic matter [1], where some of them are restricted to tropical or temperate areas, and others are present in cold-water habitats [2] Most freshwater fungi belong to the phylum Ascomycota (the ascomycetes), whose biodiversity depends on their geographical location and substrates [3]. The Dothideomycetes is among the earliest fungi that were reported in freshwater environments [5] They are a group of fungi characterized by the production of fissitunicate (bitunicate) asci in unilocular and polylocular ascomata [6,7], currently classified into two subclasses: the Dothideomycetidae, comprising the orders Capnodiales, Dothideales, and Myriangiales; and the Pleosporomycetidae, comprising the orders Gloniales, Hysteriales, Jahnulales, Mytilinidiales, and Pleosporales [8,9]. The Pleosporales is the largest order of the Dothideomycetes, comprising a quarter of its species [6,10]. Taxa in this order have been found in diverse habitats, and can act as saprobes, endophytes, pathogens, or parasites. Most of the Pleosporales are plant pathogens with a wide range of hosts and mainly cause leaf and stem lesions [6,9,11,12]

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