Antarctic strict anaerobic microbiota from Deschampsia antarctica vascular plants rhizosphere reveals high ecology and biotechnology relevance

Abstract

The Antarctic soil microbial community has a crucial role in the growth and stabilization of higher organisms, such as vascular plants. Analysis of the soil microbiota composition in that extreme environmental condition is crucial to understand the ecological importance and biotechnological potential. We evaluated the efficiency of isolation and abundance of strict anaerobes in the vascular plant Deschampsia antarctica rhizosphere collected in the Antarctic's Admiralty Bay and associated biodiversity to metabolic perspective and enzymatic activity. Using anaerobic cultivation methods, we identified and isolated a range of microbial taxa whose abundance was associated with Plant Growth-Promoting Bacteria (PGPB) and presences were exclusively endemic to the Antarctic continent. Firmicutes was the most abundant phylum (73 %), with the genus Clostridium found as the most isolated taxa. Here, we describe two soil treatments (oxygen gradient and heat shock) and 27 physicochemical culture conditions were able to increase the diversity of anaerobic bacteria isolates. Heat shock treatment allowed to isolate a high percentage of new species (63.63 %), as well as isolation of species with high enzymatic activity (80.77 %), which would have potential industry application. Our findings contribute to the understanding of the role of anaerobic microbes regarding ecology, evolutionary, and biotechnological features essential to the Antarctic ecosystem.

Niche Differentiation in the Composition, Predicted Function, and Co-occurrence Networks in Bacterial Communities Associated With Antarctic Vascular Plants

“…In addition, the sequencing of genome from culturable bacteria isolated from D. antarctica phyllosphere, showed genes associated with nutrient uptake, bioactive metabolites, and antimicrobial compounds (Cid et al, 2018). Similar to our study, Pseudomonas are commonly found in the rhizospheres and phyllospheres of Antarctic vascular plants (Teixeira et al, 2010;Peixoto et al, 2016;Cid et al, 2017). Pseudomonas is recognized as a metabolically versatile bacterial group that exhibits a wide battery of activities such as nutrient cycling, degradation of organic compounds, among others (Timmis, 2002;Loeschcke and Thies, 2015).…”

“…Microbial indicator analyses allowed identification of taxa mainly clustered into the phyla Proteobacteria, Actinobacteria, and Firmicutes, independent of niche and plant species. Members of Proteobacteria, Actinobacteria, and Firmicutes phyla are frequently reported as the dominant bacterial taxa in soil and plant microbiome in Arctic and Antarctic environments (Teixeira et al, 2010;Jorquera et al, 2016;Peixoto et al, 2016;Poosakkannu et al, 2017;Molina-Montenegro et al, 2018). In relation to three niche co-occurrence networks, our results showed significant difference among the plant niches investigated, where 5 (Microbacteriaceae, Pseudomonaceae, Lactobacillaceae, and Corynebacteriaceae), 23 (Chitinophagaceae and Sphingomonadaceae), and 7 (Rhodospirillaceae) major putative keystone taxa at family-level were observed in endosphere, phyllosphere and rhizosphere, respectively.…”

Ecology and potential functions of plant-associated microbial communities in cold environments

“…Likewise, the bacterial genus Clostridium was found to include some endemic isolates of the Antarctic environments (Peixoto et al . 2016 ).…”

“…Heterotrophy, fermentation, xenobiotic degradation, nitrogen metabolism, tryptophan metabolism and inositol metabolism were the major functional groups of plant-associated microbial communities in Antarctic regions (Peixoto et al . 2016 ; Zhang et al . 2020 ), indicating a possible adaptation strategy to harsh environmental conditions.…”

“… 2013 ; Peixoto et al . 2016 ; Yarzábal et al . 2018 ; Tiryaki, Aydın and Atıcı 2019 ; Tistechok et al .…”