Microbes inhabiting soils experience periodic water deprivation. The effects of desiccation on DNA, protein, and membrane integrity are well-described. However, the effects of drying and rehydration o...

Arthrobacter are commonly isolated from cold soil environments globally

Background Plant roots are hotspots for interactions with soil microbes, where a characteristic bacterial community structure is formed. Plant specialized metabolites often play pivotal roles in this assembly process. However, the molecular basis underlying root microbiota responses to these bioactive compounds, and how such metabolic interactions shape the assembly of host-specific root microbiota, remain largely unknown. Nicotine is a toxic alkaloid predominantly produced by the genus Nicotiana, and the genus Arthrobacter is known as one of the nicotine-degrading bacteria in the tobacco root microbiota. In this study, we used the tobacco–Arthrobacter interaction system as a model and integrated comparative genomics and experimental genetic manipulation assays to uncover the role of bacterial catabolism capacity for host specialized metabolites in shaping host-specific root microbiota. Results Nicotine catabolism genes are uniquely found in the Arthrobacter strains derived from nicotine-containing environments, and this restricted gene distribution is driven by a plasmid-mediated horizontal gene transfer. To assess the ecological consequences of this genomic adaptation in Arthrobacter fitness in tobacco roots, we characterized the nicotine utilization ability of Arthrobacter and conducted adaptation assays under in planta conditions using genetically manipulated Arthrobacter strains and tobacco mutants impaired in nicotine catabolism and biosynthesis, respectively. Nicotine improves Arthrobacter colonization of tobacco roots through a catabolism-dependent mechanism. Bacterial community analysis using a synthetic community approach further demonstrated that this metabolic adaptation enhances Arthrobacter fitness within tobacco root microbiota. Conclusions Our findings illustrated that bacterial catabolic capacity toward host-derived plant specialized metabolites is key for successful root colonization. This metabolic adaptation is driven by plasmid-mediated horizontal gene transfer and ultimately shapes the structure of the root microbiota community. Video Abstract

Deep soil horizons contain microbes crucial for subsurface biogeochemistry and the global carbon cycle. While microbial communities have been extensively studied in surface horizons, we know far less ...

De COGEM is gevraagd te adviseren over de pathogeniteitsklasse van de bacterie Arthrobacter bussei en de plaatsing van deze soort op Bijlage 2, Lijst A1 van de Regeling ggo. Deze bijlage bestaat uit l...

Antarctic soils represent one of the more extreme environments for microbial life on Earth, yet they harbor heterogeneous and diverse microbial communities. Biologists have long hypothesized that Antarctic microorganisms are unique from those found on other continents due to the extreme geographic isolation and the cold, dry, and challenging conditions typical of Antarctica. To test this hypothesis, we focused on a cosmopolitan bacterial genus, Arthrobacter, that is widely distributed across global soils. We first profiled a global metagenomic dataset from both Antarctic and non-Antarctic surface soils to quantify the distributions of Arthrobacter strains. Despite high strain-level diversity, 90% of the strains found in the Antarctic soils were only found on the continent. We then used cultivation-based phenotypic analyses and strain-level genomic comparisons to assess how Antarctic strains and non-Antarctic strains differ in their traits and environmental preferences. Not only did we find evidence of endemism, but Antarctic Arthrobacter also have genomic characteristics and environmental tolerances that suggest they are uniquely adapted to Antarctic conditions. ### Competing Interest Statement The authors have declared no competing interest. U.S. National Science Foundation, NSF 21-567, EAR 1950681 Australian Research Council, FT240100502, DE250101210

Among the genera enriched in the treated rhizosphere were Bacillus and Arthrobacter, two groups widely recognized as beneficial soil bacteria

Biologists have uncovered a unique ensemble of Arthrobacter in Antarctic soil that are unlike microbes found anywhere else on the planet.

Here, we present the genomes of two soil actinobacteria: Arthrobacter sp. strain AZCC_0090 and Mycobacterium sp. strain AZCC_0083, isolated from oligotrophic subsurface soils in Southern Arizona, USA. KEYWORDS: environmental microbiology, soil ...

24AI: alpha-1,2-glucosidase from Arthrobacter humicola A8F5, kojibiose complex

A forest fire sweeps everything in its path. It drastically alters the soil environment, causing extreme temperatures, reduced moisture, spikes in pH, the release of inorganic nitrogen, a sharp declin...

Published in The Science of the total environment