The soil and plant determinants of community structures of the dominant actinobacteria in Marion Island terrestrial habitats, Sub-Antarctica

Abstract

Marion Island is a Sub-Antarctic island made up of distinct ecological habitats based on soil physiochemical, plant cover and physical characteristics. The microbial diversity and ecological determinants in this harsh Sub-Antarctic environment are largely uncharacterized. Actinobacteria have diverse ecological functions related to soil and plant functioning. This study was aimed at characterizing the diversity and community structures of the dominant actinobacteria in the distinct habitats and to identify their determinant soil and plant characteristics. Using the 16S rRNA gene, the denaturing gradient gel electrophoresis patterns and clone library diversity were correlated with the soil and plant characteristics. Multivariate statistical methods were also used to identify determinant soil and plant characteristics. Salinity and pH were the most important soil determinants, and a number of important site-specific plant species may have been important. The Coastal Fellfield Habitat was dominated by sequences of the suborders Micrococcineae (44%) andPropionibacterineae (18%), with salinity identified as the principal determinant. The Cotula Herbfield Habitat was dominated by Frankineae (37%) and Streptosporangineae (38%), which were correlated with organic nutrient concentrations. The Wet Mire Habitat was dominated by Acidimicrobineae (61%), with moisture and organic carbon content as principal components. Culture-dependent studies were complementary to culture-independent studies with the majority of actinobacteria isolated not identified in 16S rRNA gene clone libraries. This study demonstrates how the soil physiochemical characteristics and plant species independently determine the community structures of the dominant actinobacteria in distinct ecological habitats. These factors subsequently influence their ecological adaptation, roles and functions.

Bacterial community structure on two alpine debris-covered glaciers and biogeography of Polaromonas phylotypes

“…The dominant taxon was the Actinobacteridae that represented 27% and 22% of the classified sequences at Miage and Belvedere glaciers, respectively. Most of these sequences were classified as Micrococcineae and Propionibacterineae, in accordance with recent studies specifically addressing the structure of Actinobacteria in cold environments (Jiang et al, 2010;Sanyika et al, 2012). Moreover, Actinobacteridae are ubiquitous in soils under very different climatic conditions (Madigan et al, 2009) and their high abundance is consistent with the presence of OC in the sediments, despite that the average OC content of debris sampled in Miage and Belvedere glaciers was 0.83 (0.72 s.d.)…”

Characteristics of Soil Physicochemical Properties and Microbial Community of Mulberry (Morus alba L.) and Alfalfa (Medicago sativa L.) Intercropping System in Northwest Liaoning

“…TP is the most important factor affecting Actinobacteria. This is not completely consistent with Sanyika’s results on soil determinants of actinomycetes community structure [ 61 ]. TC, TN, C: P and N: P were the main influencing factors of the fungal community, and were significantly positively correlated with the dominant phylum Ascomycota, while negatively correlated with most phylum fungi.…”

A Deeper Look into the Biodiversity of the Extremely Acidic Copahue volcano-Río Agrio System in Neuquén, Argentina

“…In the particular case of Sulfuriferula, it has also been detected by high-throughput sequencing in an acidic water reservoir (pH 2.85, temperature 13.2 • C) of an open-cast mine for polymetallic ores in Eastern Siberia [36]. The genera Ferrithrix has been reported in the volcanic island of Marion located, in the South African zone of sub-Antarctica where the annual temperature mean ranges 5-6 • C [37], and even in the rock coatings in the glacial valley of the Northern Caledonide Mountains of Swedish Lapland where the annual temperature mean is −1 • C [38]. Finally, it is worth noting that the sequences obtained from LV present identity percentages lower than 97% with cultured characterized species, thus they could be potential autochthonous novel species with different optimal growth conditions.…”