Abstract Detail

Mycological Section

Brown, Shawn [1], Heath, Katy [2], Dalling, Jim [3], Mosquera, Sergio [4], Suarez, Yaravi [4], Ferrer, Astrid [1].

Community assembly, phylogenetic diversity, and function of decomposing aquatic fungi along a salinity gradient.

Wood decomposition plays a major role in global nutrient cycling patterns and is a process largely dominated by fungi. On land, studies on the assembly of wood decomposers are confounded by complex mycelial networks in the soil that makes community wide analyses of decomposing fungi difficult. Here we focus on aquatic and marine systems whose fungal decomposers must adhere directly onto wood to allow for direct decomposition by fungi. Aquatic and marine fungi that can decompose wood are more phylogenetically restricted than terrestrial fungi with the majority of taxa belonging to a few Classes within Ascomycota. Here we explore community-wide and functional assembly of decomposing fungi across a salinity gradient (marine to freshwater) using an integrated approach in three Panamanian rivers. We harvested sticks from a common tropical tree species (West Indian Elm; Guazuma ulmifolia) and submersed them along a salinity gradient (marine to brackish to freshwater) in three rivers on Isla de Coiba (Coiba National Park, Panama). Every ca. three months for 18 months, sticks were retrieved for total microbial genomic DNA extraction from bark and wood, wet-incubation of sticks to produce single spore isolation cultures, and wood chemical structural component analyses. We targeted the Large Subunit (LSU) region for community sequencing (Illumina HiSeq) after different primer combinations were tested for suitability using single spore isolate cultures as a local mock community via Fluidigm IFC micro-fluidic amplification and MiSeq Nano reaction. In addition to Fungi, Bacteria and Archaea were also sequenced (Fluidigm and HiSeq) on a total of 384 samples. Additionally, biodiversity and phylogenetic analyses on ~400 unique single-spore cultures are ongoing. Further, select cultures (fungi found only in freshwater or marine environments) and a subsample of environmental samples were queried (RNA-Seq) for functional gene expression to determine how salinity affects production of carbohydrate activated enzymes (CAZy) and if pioneering fungal decomposing communities posses functional redundancy independent of salinity. Fungal communities are strongly structured with salinity. Wood decomposing fungi found in marine environment are dramatically distinct from freshwater fungi with brackish fungal communities falling in between these two extremes. Additionally, freshwater and marine fungi differ in successional and phylogenetic diversity trajectories suggesting community assembly in different salinities follows different rules. Early results on saline influences on functional gene expression suggest that salinity alters gene expression but functional redundancy within organisms continues to allow fungal decay of wood.

1 - University of Illinois at Urbana-Champaign, Plant Biology, 133 Morrill Hall, 505 S. Goodwin Ave, Urbana, IL, 61801, USA
2 - University of Illinois at Urbana-Champaign, Plant Biology, 249 Morrill Hall, 505 S. Goodwin Ave, Urbana, IL, 61801, USA
3 - University of Illinois at Urbana-Champaign, Plant Biology, 149 Morrill Hall, 505 S. Goodwin Ave, Urbana, IL, 61801, USA
4 - Smithsonian Tropical Research Institute, Ancon, Panama

Keywords:
lignocellulose decomposition
Fungi
Community Assembly
phylogenetic diversity
Aquatic.

Presentation Type: Oral Paper:Papers for Sections
Session: 29
Location: Salon 1/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 9:00 AM
Number: 29005
Abstract ID:195
Candidate for Awards:None