Genomic Insights of an Andean Multi-resistant Soil Actinobacterium of Biotechnological Interest

Abstract

Central Andean Ecosystems (between 2000 and 6000 masl) are typical arid to semiarid environments suffering from the highest total solar and UVB radiation on the planet but displaying numerous salt flats and shallow lakes. Isolated from these environments, Andean Microbial Communities (AME) of exceptional biodiversity endures multiple severe conditions. Also, the poly-extremophilic nature of AME’s microbes indicates the potential for biotechnological applications. In this context, the presented study used genome mining and physiological characterization to reveal the multi-resistant profile of Nesterenkonia sp. Act20, an actinobacterium isolated from the soil surrounding Lake Socompa, Salta, Argentina (3570 m). UV-B, desiccation, and copper assays showed the strain’s exceptional resistance to all these factors. Act20’s genome presented coding sequences involving antibiotics, low temperatures, UV and arsenic resistance, nutrient limiting conditions, osmotic stress response, low atmospheric oxygen pressure, heavy metal stress, and resistance to fluoride and chlorite. Act20 can also synthesize proteins and natural products such as an insecticide, bacterial cellulose, ectoine, bacterial hemoglobin, and even antibiotics like colicin V and aurachin C. We also found numerous enzymes for animal and vegetal biomass degradation and application in other industrial processes.The herein report shed light on the microbial adaptation to high-altitude environments, its possible extrapolation for studying other extreme environments of relevance, and its application to industrial and biotechnological processes.HIGHLIGHTSArid Andean Soils are attractive sources of microbial strains useful in biotechnological processes.Physiological studies revealed the multi-resistant nature of the poly-extremophile Nesterenkonia sp. Act20.Act20’s genome analysis showed a complete set of genes coding for proteins involved in resistance to multiple stresses, including extremoenzymes and extremolytes.

Proteomic Signatures of Microbial Adaptation to the Highest UV-Irradiation on Earth: Lessons from a Soil Actinobacterium

“…The minimal UV-B dose set in our assay reduced the cell viability of Act20 by two or three orders of magnitude depending on the treatment, without any significant notorious influence in recovery treatments. DSM 15474 was inhibited entirely with doses above 9.72 kJ/m² in all treatments, whereas Act20 tolerated higher UV-B doses than N. halotolerans, confirming the high UV-resistance profile of the Puna actinobacterium (Alonso-Reyes, Farias, et al, 2020;Alonso-Reyes, Galván, et al, 2020;Portero et al, 2019;Rasuk et al, 2017). Interestingly, the viability of Act20 was proportionally reduced in agreement to the cumulative irradiation when this strain was exposed to continuous UV-B pulses and allowed to recover in darkness.…”

“…Genomics and ultrastructural and physiological assays identified a number of UV-resistance mechanisms of bacterial and archaeal strains (Albarracín et al, 2009(Albarracín et al, , 2012Albarracín, Kraiselburd, et al, 2016;Alonso-Reyes, Farias, et al, 2020;Alonso-Reyes, Galván, et al, 2020;Flores et al, 2009;Kurth et al, 2015;Portero et al, 2019;Rasuk et al, 2017;Toneatti et al, 2017;Zenoff, Heredia, et al, 2006;.…”