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Abstract Detail



Ecology/Pathology

Oono, Ryoko [1], Lefèvre, Emilie [2], Simha, Anita [3], Lutzoni, François [2].

Community species richness of foliar fungal endophytes decrease from seedling to adult pine needles.

Fungal endophytes living inside tissues of woody plants are phylogenetically diverse even within a single leaf, commonly spanning multiple classes within Ascomycota and Basidiomycota. The community assembly and structure of endophyte species have been shown to depend on host taxa and geography, but there is relatively little known how they change as a plant matures over time. Differences in foliar endophyte communities between adult and seedling tissues of the same host taxa at the same time and place may reveal endophyte species that are specialized or selected for their important functional roles at different life stages of their hosts. Hence, we compared the communities of foliar fungal endophytes between seedling and adult needles of loblolly pines (Pinus taeda) during the summer and winter seasons in North Carolina’s Duke Forest. We used both culturing and cloning methods to sequence the endophytes’ internal transcribed spacer (ITS) and partial large subunit ribosomal DNA regions. The sequences were used to delimit operational taxonomic units (OTUs) based on 98% sequence similarity and to phylogenetically characterize the communities of foliar fungal endophytes. Culturing indicated approximately double the infection frequency in adult needles than in seedlings, but both culturing and cloning results revealed that species richness and diversity of foliar endophytes were higher in seedling needles than in adults. Sequencing cultures revealed 80 OTUs over the year, where seedling and adult needles shared 21 OTUs, seedlings had 41 OTUs not found in adults, and adults had 18 OTUs not found in seedlings. Nearly half of non-singleton OTUs overlapped between seasons for both adult (7/14) and seedling (8/19) needles with culturing methods. Cloning revealed 26 more OTUs that were not found by culturing, 16 of which were singletons found in seedlings and 2 of which were singletons found in adults. Our data suggest that seedling needles are receptive to a more diverse group of fungal endophytes than adult needles either due to differences in microclimate, tissue physiology and biochemistry, innate immunity or a combination of these factors. The two most commonly found OTUs in adult needles using both culturing and cloning methods were rarely found in seedlings. Further investigation of such endophyte species may reveal their important functions that are unique to adult tissues.  


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1 - University of California - Santa Barbara, Ecology, Evolution, and Marine Biology, Santa Barbara, California, 93106, United States
2 - Duke University, Department Of Biology, Box 90338, Durham, NC, 27708, USA
3 - University of North Carolina - Chapel Hill, NC, United States

Keywords:
endophyte
pine
community structure.

Presentation Type: Offered Paper - Paper
Session: 9
Location: Room 104 AB/Kellogg Hotel and Conference Center
Date: Tuesday, June 10th, 2014
Time: 8:30 AM
Number: 9001
Abstract ID:212
Candidate for Awards:None


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