title: Leaf-associated fungal diversity in acidified streams: insights from combining traditional and molecular approaches.
abstract: We combined microscopic and molecular methods to investigate fungal assemblages on alder leaf litter exposed in the benthic and hyporheic zones of five streams across a gradient of increasing acidification for 4 weeks. The results showed that acidification and elevated Al concentrations strongly depressed sporulating aquatic hyphomycetes diversity in both zones of streams, while fungal diversity assessed by denaturing gradient gel electrophoresis (DGGE) appeared unaffected. Clone library analyses revealed that fungal communities on leaves were dominated by members of Ascomycetes and to a lesser extent by Basidiomycetes and Chytridiomycetes. An important contribution of terrestrial fungi was observed in both zones of the most acidified stream and in the hyporheic zone of the reference circumneutral stream. The highest leaf breakdown rate was observed in the circumneutral stream and occurred in the presence of both the highest diversity of sporulating aquatic hyphomycetes and the highest contribution to clone libraries of sequences affiliated with aquatic hyphomycetes. Both methods underline the major role played by aquatic hyphomycetes in leaf decomposition process. Our findings also bring out new highlights on the identity of leaf-associated fungal communities and their responses to anthropogenic alteration of running water ecosystems.
authors.affiliation: Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Université de Lorraine, UMR 7360, Campus Bridoux rue du Général Delestraint, 57070, Metz, France; LIEC, CNRS, UMR 7360, 57070, Metz, France.
authors.forename: Hugues
authors.initials: H
authors.lastname: Clivot
authors.forename: Julien
authors.initials: J
authors.lastname: Cornut
authors.forename: Eric
authors.initials: E
authors.lastname: Chauvet
authors.forename: Arnaud
authors.initials: A
authors.lastname: Elger
authors.forename: Pascal
authors.initials: P
authors.lastname: Poupin
authors.forename: François
authors.initials: F
authors.lastname: Guérold
authors.forename: Christophe
authors.initials: C
authors.lastname: Pagnout
mesh_terms: D029661:Alnus / Q000382:microbiology; D000595:Amino Acid Sequence; D001203:Ascomycota / Q000145:classification / Q000235:genetics*; D001487:Basidiomycota / Q000145:classification / Q000235:genetics*; D001673:Biodegradation, Environmental; D058645:Denaturing Gradient Gel Electrophoresis; D006863:Hydrogen-Ion Concentration; D059013:Microbial Consortia / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D018515:Plant Leaves / Q000382:microbiology*; D012337:RNA, Ribosomal, 18S / Q000235:genetics*; D045483:Rivers / Q000382:microbiology
chemical_list: D012337:RNA, Ribosomal, 18S