Abstract Detail

Ecology/Pathology

Hesse, Cedar N. [1], Vuyisich, Momochillo [1], Gallegos-Graves, La Verne [1], Challacombe, Jean F. [1], Ticknor, Lawerence O. [2], Zak, Donald R. [3], Kuske, Cheryl R. [1].

Metatranscriptomes from maple forest leaf litter reveal decreased community expression of fungal lignocellulytic enzymes under elevated atmospheric N deposition.

A diverse community of bacteria and fungi mediate plant litter decay in forests, within which they regulate the cycling and storage of C and N in soil. Anthropogenic deposition of N can slow decay and increase soil C storage, however, the microbial mechanisms mediating a reduction in decay are unknown. We developed a metatranscriptome approach using Illumina sequencing that significantly enriched for mRNA in a forest floor RNA pool, and that included both eukaryote (primarily fungal) and bacterial transcripts. We compared the transcriptional profiles in the forest floor of two maple forests in northern Michigan, USA. Within each forest, the impact of 18 years of experimental N deposition on community gene expression was compared. KEGG mapping demonstrated that this metatranscriptome sequencing comprehensively sampled the central metabolic pathways of both fungi and bacteria. K-mer based comparisons of replicate, total metatranscriptomes illustrated significant differences in community gene expression patterns between the two maple forests, even though the sites were matched for ecological characteristics. Comparison of CAZy enzyme expression profiles detected distinct differences in metabolic responses to N deposition. Transcriptional response to N deposition was largely site-specific although a general reduction in the relative abundance of fungal lignocellulytic enzymes was observed at both sites. This new metatranscriptome approach provided simultaneous gene expression profiles of fungi and bacteria in large scale field experiments, and has identified candidate genes and pathways involved in litter decomposition and response to chronic atmospheric N deposition.

1 - Los Alamos National Laboratory, Bioscience Division, PO Box 1663 M888, Los Alamos, NM, 87545, United States
2 - Los Alamos National Laboratory, Computer, Computational, and Statistical Sciences Division , PO Box 1663 F600, Los Alamos, NM, 87545, United States
3 - University of Michigan, Department of Ecology and Evolutionary Biology, 2019 Kraus Nat. Sci. Bldg., 830 North University, Ann Arbor, MI, 48109-1048, United States

Keywords:
metatranscriptomics
Metagenomics
nitrogen
CAZy
lignocellulose.

Presentation Type: Offered Paper - Paper
Session: 15
Location: Auditorium/Kellogg Hotel and Conference Center
Date: Wednesday, June 11th, 2014
Time: 10:30 AM
Number: 15001
Abstract ID:160
Candidate for Awards:None