Limits...
Litter Breakdown and Microbial Succession on Two Submerged Leaf Species in a Small Forested Stream.

Newman MM, Liles MR, Feminella JW - PLoS ONE (2015)

Bottom Line: PLFA revealed a significant time effect on microbial lipid profiles for both leaf species.Next-generation sequencing revealed temporal shifts in dominant taxa within the phylum Proteobacteria, whereas γ-Proteobacteria dominated pre-immersion and α- and β-Proteobacteria dominated after 1 month of instream incubation; the latter groups contain taxa that are predicted to be capable of using organic material to fuel further breakdown.Our results suggest that incubation time is more important than leaf species physicochemistry in influencing leaf litter microbial assemblage composition, and indicate the need for investigation into seasonal and temporal dynamics of leaf litter microbial assemblage succession.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America.

ABSTRACT
Microbial succession during leaf breakdown was investigated in a small forested stream in west-central Georgia, USA, using multiple culture-independent techniques. Red maple (Acer rubrum) and water oak (Quercus nigra) leaf litter were incubated in situ for 128 days, and litter breakdown was quantified by ash-free dry mass (AFDM) method and microbial assemblage composition using phospholipid fatty acid analysis (PLFA), ribosomal intergenic spacer analysis (RISA), denaturing gradient gel electrophoresis (DGGE), and bar-coded next-generation sequencing of 16S rRNA gene amplicons. Leaf breakdown was faster for red maple than water oak. PLFA revealed a significant time effect on microbial lipid profiles for both leaf species. Microbial assemblages on maple contained a higher relative abundance of bacterial lipids than oak, and oak microbial assemblages contained higher relative abundance of fungal lipids than maple. RISA showed that incubation time was more important in structuring bacterial assemblages than leaf physicochemistry. DGGE profiles revealed high variability in bacterial assemblages over time, and sequencing of DGGE-resolved amplicons indicated several taxa present on degrading litter. Next-generation sequencing revealed temporal shifts in dominant taxa within the phylum Proteobacteria, whereas γ-Proteobacteria dominated pre-immersion and α- and β-Proteobacteria dominated after 1 month of instream incubation; the latter groups contain taxa that are predicted to be capable of using organic material to fuel further breakdown. Our results suggest that incubation time is more important than leaf species physicochemistry in influencing leaf litter microbial assemblage composition, and indicate the need for investigation into seasonal and temporal dynamics of leaf litter microbial assemblage succession.

No MeSH data available.


Relative abundance of class- and phylum-level bacterial taxa.Data derived from bar-coded next-generation sequencing of 16S rRNA gene amplicons and represent taxa affiliation summaries for both leaf species (maple and oak) following 0, 32, and 128 days in stream incubation. Classes representing <0.5% in all samples were grouped and represented as “Other” for their given phylum, whereas phyla representing <0.5% of all sequences were grouped as “Other Bacterial Classes”.
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pone.0130801.g006: Relative abundance of class- and phylum-level bacterial taxa.Data derived from bar-coded next-generation sequencing of 16S rRNA gene amplicons and represent taxa affiliation summaries for both leaf species (maple and oak) following 0, 32, and 128 days in stream incubation. Classes representing <0.5% in all samples were grouped and represented as “Other” for their given phylum, whereas phyla representing <0.5% of all sequences were grouped as “Other Bacterial Classes”.

Mentions: A summary of taxa obtained from next-generation 16S rRNA gene sequencing is presented in Fig 6 for both the phylum and class levels. The phylum Proteobacteria dominated both maple and oak over the study, although the dominant class varied with date. Prior to instream incubation, maple and oak both contained mostly γ-Proteobacteria (54.0 and 56.6%, respectively) and also α-Proteobacteria (17.8% maple; 14.1% oak). Many of the γ-Proteobacteria came from the families Aeromonadaceae, Enterobacteriaceae, and Pseudomonadaceae. Abundance of α-Proteobacteria before incubation was mostly taxa from the orders Rhizobiales and Sphingomonadales.


Litter Breakdown and Microbial Succession on Two Submerged Leaf Species in a Small Forested Stream.

Newman MM, Liles MR, Feminella JW - PLoS ONE (2015)

Relative abundance of class- and phylum-level bacterial taxa.Data derived from bar-coded next-generation sequencing of 16S rRNA gene amplicons and represent taxa affiliation summaries for both leaf species (maple and oak) following 0, 32, and 128 days in stream incubation. Classes representing <0.5% in all samples were grouped and represented as “Other” for their given phylum, whereas phyla representing <0.5% of all sequences were grouped as “Other Bacterial Classes”.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4476575&req=5

pone.0130801.g006: Relative abundance of class- and phylum-level bacterial taxa.Data derived from bar-coded next-generation sequencing of 16S rRNA gene amplicons and represent taxa affiliation summaries for both leaf species (maple and oak) following 0, 32, and 128 days in stream incubation. Classes representing <0.5% in all samples were grouped and represented as “Other” for their given phylum, whereas phyla representing <0.5% of all sequences were grouped as “Other Bacterial Classes”.
Mentions: A summary of taxa obtained from next-generation 16S rRNA gene sequencing is presented in Fig 6 for both the phylum and class levels. The phylum Proteobacteria dominated both maple and oak over the study, although the dominant class varied with date. Prior to instream incubation, maple and oak both contained mostly γ-Proteobacteria (54.0 and 56.6%, respectively) and also α-Proteobacteria (17.8% maple; 14.1% oak). Many of the γ-Proteobacteria came from the families Aeromonadaceae, Enterobacteriaceae, and Pseudomonadaceae. Abundance of α-Proteobacteria before incubation was mostly taxa from the orders Rhizobiales and Sphingomonadales.

Bottom Line: PLFA revealed a significant time effect on microbial lipid profiles for both leaf species.Next-generation sequencing revealed temporal shifts in dominant taxa within the phylum Proteobacteria, whereas γ-Proteobacteria dominated pre-immersion and α- and β-Proteobacteria dominated after 1 month of instream incubation; the latter groups contain taxa that are predicted to be capable of using organic material to fuel further breakdown.Our results suggest that incubation time is more important than leaf species physicochemistry in influencing leaf litter microbial assemblage composition, and indicate the need for investigation into seasonal and temporal dynamics of leaf litter microbial assemblage succession.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Auburn University, Auburn, Alabama, United States of America.

ABSTRACT
Microbial succession during leaf breakdown was investigated in a small forested stream in west-central Georgia, USA, using multiple culture-independent techniques. Red maple (Acer rubrum) and water oak (Quercus nigra) leaf litter were incubated in situ for 128 days, and litter breakdown was quantified by ash-free dry mass (AFDM) method and microbial assemblage composition using phospholipid fatty acid analysis (PLFA), ribosomal intergenic spacer analysis (RISA), denaturing gradient gel electrophoresis (DGGE), and bar-coded next-generation sequencing of 16S rRNA gene amplicons. Leaf breakdown was faster for red maple than water oak. PLFA revealed a significant time effect on microbial lipid profiles for both leaf species. Microbial assemblages on maple contained a higher relative abundance of bacterial lipids than oak, and oak microbial assemblages contained higher relative abundance of fungal lipids than maple. RISA showed that incubation time was more important in structuring bacterial assemblages than leaf physicochemistry. DGGE profiles revealed high variability in bacterial assemblages over time, and sequencing of DGGE-resolved amplicons indicated several taxa present on degrading litter. Next-generation sequencing revealed temporal shifts in dominant taxa within the phylum Proteobacteria, whereas γ-Proteobacteria dominated pre-immersion and α- and β-Proteobacteria dominated after 1 month of instream incubation; the latter groups contain taxa that are predicted to be capable of using organic material to fuel further breakdown. Our results suggest that incubation time is more important than leaf species physicochemistry in influencing leaf litter microbial assemblage composition, and indicate the need for investigation into seasonal and temporal dynamics of leaf litter microbial assemblage succession.

No MeSH data available.