Similar Diversity of Alphaproteobacteria and Nitrogenase Gene Amplicons on Two Related Sphagnum Mosses

Abstract

Sphagnum mosses represent a main vegetation component in ombrotrophic wetlands. They harbor a specific and diverse microbial community with essential functions for the host. To understand the extend of host specificity and impact of environment, Sphagnum fallax and Sphagnum angustifolium, two phylogenetically closely related species, which show distinct habitat preference with respect to the nutrient level, were analyzed by a multifaceted approach. Microbial fingerprints obtained by PCR-single-strand conformation polymorphism of 16S rRNA and nitrogenase-encoding (nifH) genes were highly similar for both Sphagnum species. Similarity was confirmed for colonization patterns obtained by fluorescence in situ hybridization (FISH) coupled with confocal laser scanning microscopy (CLSM): Alphaproteobacteria were the main colonizers inside the hyaline cells of Sphagnum leaves. A deeper survey of Alphaproteobacteria by 16S rRNA gene amplicon sequencing reveals a high diversity with Acidocella, Acidisphaera, Rhodopila, and Phenylobacterium as major genera for both mosses. Nitrogen fixation is an important function of Sphagnum-associated bacteria, which is fulfilled by microbial communities of Sphagna in a similar way. NifH libraries of Sphagnum-associated microbial communities were characterized by high diversity and abundance of Alphaproteobacteria but contained also diverse amplicons of other taxa, e.g., Cyanobacteria and Deltaproteobacteria. Statistically significant differences between the microbial communities of both Sphagnum species could not be discovered in any of the experimental approach. Our results show that the same close relationship, which exists between the physical, morphological, and chemical characteristics of Sphagnum mosses and the ecology and function of bog ecosystems, also connects moss plantlets with their associated bacterial communities.

Biochemical determinants of litter quality in 15 species of Sphagnum

“…To avoid collapse of the large but empty hyaline cells, their secondary walls are strengthened by rib-like fibrils. The fibrils exhibit intensive autofluorescence emitted by lignin-like phenolics (see Bragina et al 2012 for photographs) proposing a structural function of the phenolic polymer. The lignin-like phenolics (together with hemicelluloses (Scheller and Ulvskov 2010)) provide the hyaline cells with rigidity preventing their collapse, e.g.…”

Comparative Study of Bacterial Communities in Nepenthes Pitchers and Their Correlation to Species and Fluid Acidity

“…Members of Acidocella have been discovered both in natural and acid mine drainage environments presenting high heavy-metal levels [57][58][59][60]. They have also been found among Sphagnum moss microbiota growing under varying acidic conditions [61,62]. Four species of this genus are currently recognized including A. facilis [63], A. aminolytica [64], A. aluminiidurans [65], and A. aromatic [66].…”

FunGene: the functional gene pipeline and repository

“…An incomplete list citing FGR and FGP includes projects studying microbial communities from various habitats as a reference database (Spain et al, 2007; Wertz et al, 2009; Bull et al, 2012; Lin et al, 2012; Fang et al, 2013), a primer designing/testing tool (Henry et al, 2006; Philippot and Hallin, 2006; Bru et al, 2007; Leigh et al, 2007; Stedtfeld et al, 2007; Jones et al, 2008, 2011, 2012; Stres and Murovec, 2008, 2009; Iwai et al, 2010; Oakley et al, 2010, 2012; Suenaga, 2012; Vital et al, 2013), and a data processing/analysis pipeline (Bragina et al, 2011, 2013; Grube et al, 2012). …”