Abstract Detail

Poster Session

Obase, Keisuke [1], Douhan, Greg W. [2], Yosuke, Matsuda [3], Smith, Matthew E. [1].

Culturable fungal biota growing on Cenococcum sclerotia in forest soil.

Cenococcum geophilum (Ascomycota, Dothidiomycetes) is an ectomycorrhizal fungus with a wide host range and a nearly global distribution. The ubiquitous presence of C. geophilum in many forests around the globe is often attributed to its ability to form sclerotia, which are black, sphaerical, smooth, and range in size from 0.5-4.0 mm in diameter. Fungi that colonize sclerotia appear to decrease sclerotia viability and therefore may play an important role in the life history of Cenococcum but no studies have investigated this hypothesis. Therefore, we used culture-based methods to document the communities of fungi growing inside surface-sterilized sclerotia collected from forest soils. We collected 971 Cenococcum sclerotia from 10 different mixed oak-pine forests in Florida and cultured them on modified Melin Norkrans media. Fungal isolates were obtained from 728 sclerotia and 571 isolates have been identified with molecular techniques. Cenococcum was successfully isolated from 220 sclerotia whereas 351 sclerotia hosted fungi other than Cenococcum. DNA barcoding of the ITS rDNA from these fungi yielded 82 operational taxonomical units (OTUs; 97% sequence similarity cutoff), which consisted primarily of taxa belonging to the Ascomycota (e.g., Chaetothyriales, Eurotiales, Helotiales, Pleosporales, Sordariales) and a few Basidiomycota (Hymenochaetales, Russulales) and Zygomycota (Umbelopsis). Although the majority of fungal OTUs were cultured from sclerotia from only one or two forest sites, several other sclerotia-associated fungi were found across many of the 10 forests. For example, a Russulales OTU was collected at 8 sites, one Oidiodendron OTU was collected at 6 sites, and both a Cladophialophora OTU and Dothidiomycete OTU were collected at 5 sites. The results of this study suggest that Cenococcum sclerotia act as a substrate for diverse fungi. Although most of the fungi we cultured were rare on Cenococcum sclerotia, the occurrence of several OTUs in sclerotia across many sites suggests that these fungi may be active parasites of Cenococcum sclerotia or saprophytically use dead sclerotia as a carbon source.

1 - University of Florida, Plant pathology, 2517 Fifield Hall, Gainesville, FL, 32611-0680, USA
2 - Riverside, CA, USA
3 - Mie university, Graduate School of Bioresource, Kurimamachiya 1577, Tsu, Mie, 514-8507, Japan

Keywords:
Ascomycota
Cenococcum geophilum
ectomycorrhizal fungi
Parasite
sclerotium.

Presentation Type: Offered Paper - Poster
Session: P2
Location: Lincoln Room/Kellogg Hotel and Conference Center
Date: Tuesday, June 10th, 2014
Time: 8:00 PM
Number: P2005
Abstract ID:93
Candidate for Awards:None