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Abstract Detail



Symbioses: Plant, Animal, and Microbe Interactions

Chen, Ko-Hsuan [1], Liao, Hui-Ling [1], Arnold, A. Elizabeth [2], Lutzoni, François [1].

Using metatranscriptomics to characterize functional shifts in endophytic fungi at plant senescence: Are endophytic fungi latent saprotrophs?

Endophytic fungi live inside healthy plants but do not cause obvious symptoms. The same fungal species can often be isolated from living and senescent tissues of the same plant, consistent with the widespread hypothesis that many endophytic fungi are saprotrophs during part of their life cycle. However, these investigations are mostly based on culture-dependent or DNA-based environmental sampling methods. It is not known whether fungal strains detected in healthy and senescent plant tissues are functionally active under both conditions, and which genetic mechanisms are involved in this functional transition. To gain a better understanding of endophytism-saprotrophism transitions in situ, we sequenced the metatranscriptome of the broom moss Dicranum scoparium, and its microbiota, which were sampled from local forest sites in North Carolina. Three distinct layers (healthy, senescent, and dead tissue) can be recognized from the top to the base of the gametophytes of D. scoparium. We extracted total RNA from these three layers. Illumina Hi-Seq sequencing generated about 39 million qualified reads for each individual layer sample. By using NCBI GenBank and a customized database of the DoB project (Dimensions of Biodiversity; EndoBiodiversity.org), we were able to extract reads that mapped to the D1/D2 region of fungal ribosomal large subunit gene using Bowtie2. Through de novo assembly using Velvet, followed by BLASTN, we identified several fungi that are functionally active throughout the three gametophytic layers of D. scoparium, including: Rickenella, Sistotrema, Cladophialophora, Epibryon and Mortierella. We also found fungal taxa that were active only in the youngest, photosynthetic, layer (e.g., Hyaloscypha). We further compared gene expression patterns of fungi under various degrees of host senescence to determine the molecular mechanisms involved in transitions between saprotrophism and symbiotrophism. Our study sheds light on the potential for ecologically important functional shifts in host use.


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1 - Duke University, Department of Biology, 130 Science Dr., Durham, NC, 27708, USA
2 - University of Arizona, School of Plant Sciences, 1140 E. South Campus Drive, Forbes 303, Tucson, AZ, 85721, USA

Keywords:
Endophytic fungi
metatranscriptome
symbiosis
Bryophyte.

Presentation Type: Oral Paper:Papers for Topics
Session: 51
Location: Salon 5/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 4:15 PM
Number: 51011
Abstract ID:1231
Candidate for Awards:MSA Best Oral Presentation Award by a Graduate Student


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