Copiapoa solaris is an endemic cactus species from the Antofagasta region, Chile, thriving in arid coastal ecosystems known as “fog oases,” where the rising marine moisture is the primary water source. This study investigates the role of microbial communities associated with the rhizosphere of C. solaris in adapting to extreme environmental conditions, particularly focusing on the acdS gene, which encodes ACC deaminase—an enzyme that reduces ethylene production under stress. This research aims to elucidate the gene’s contribution to the adaptation of C. solaris in these challenging environments. Samples were collected from three sites (El Cobre, Quebrada Botija, and Quebrada Izcuña) that differ in relative humidity, temperature, and topography. Environmental DNA was extracted, phylogenetic diversity was analyzed, and metagenomic annotation of the acdS gene was conducted. The acdS gene was detected in all samples, with the highest relative abundance at Quebrada Izcuña (0.05%), characterized by low relative humidity (<70%) and severe water stress. Phylogenetic analysis revealed conserved sequences across sites, while taxonomic and alpha diversity were similar among them. However, beta diversity indicated that Quebrada Izcuña was the least homogeneous, hosting distinct taxa potentially associated with stress mitigation. The acdS gene was detected on plasmids at El Cobre and Quebrada Izcuña, suggesting its potential mobility within the metagenome. The results of this study highlight the intricate relationships between microbial communities and the resilient cactus species C. solaris in extreme environments. The conservation and abundance of the acdS gene, particularly in low-humidity conditions, suggest its vital role in facilitating stress tolerance through microbial interactions. Understanding these dynamics is crucial for developing strategies to enhance plant resilience in arid ecosystems, with potential applications in sustainable agriculture and ecosystem management under changing climatic conditions.

The thermophilic bacterium Thermus thermophilus represents a crucial genetic reservoir for exploring thermostable enzymes as valuable biocatalysts for industrial and biotechnology applications. Here, we identify, clone, and characterize Ces1-ET, Est1-ET, and Plp1-ET, three lipolytic enzymes obtained from T. thermophilus strain ET-1 isolated from El Tatio Geothermal Field in Northern Chile. To enable recombinant expression, we constructed the pTGT-1 expression system, a versatile bifunctional shuttle vector compatible with both Escherichia coli and T. thermophilus. The three thermoenzymes Ces1-ET, Est1-ET, and Plp1-ET, were successfully cloned, expressed, and purified using the pTGT-1 system, with a molecular mass of 25 kDa, 36 kDa, and 28 kDa, respectively. The recombinant purified enzymes displayed optimal temperatures at 60 °C, 80 °C, and 70 °C and optimal pH of 7.5, 9.0, and 8.0 for Ces1-ET, Est1-ET, and Plp1-ET, respectively. Functional biochemical assays revealed a broad tolerance to surfactants, detergents, divalent cations, and high salinity, relevant properties for their application in an industrial setting. These thermostable esterases expand the repertoire of thermozymes from Thermus spp., introducing pTGT-1 as an innovative tool for thermophilic protein expression and highlighting T. thermophilus strain ET-1 from El Tatio Geothermal Field as a valuable source of thermostable enzymes for industrial and biotechnology applications.

Geothermal ecosystems constitute important reservoirs of thermophilic microorganisms and their associated metabolic functions; however, the genome-resolved diversity and enzymatic potential of high-altitude geothermal systems remain poorly characterized. Here, we applied shotgun metagenomics and genome-resolved approaches to investigate thermophilic microbial communities inhabiting geothermal sediments from the El Tatio geothermal field, a polyextreme hydrothermal system located at ~4300 m above sea level in the Andean Altiplano of northern Chile. Genome reconstruction yielded 657 metagenome-assembled genomes (MAGs), including 190 near-complete and 273 high-quality genomes, providing a comprehensive genome-resolved view of microbial diversity in this environment. Taxonomic analyses revealed diverse archaeal and bacterial communities dominated by members of Thermoproteota, Methanobacteriota, Deinococcota, and Actinomycetota. Functional screening identified 612 high-confidence putative hydrolase-encoding genes distributed across multiple thermophilic lineages, including genes associated with esterases, lipases, proteases, and glycoside hydrolases. Notably, several candidates were recovered from archaeal MAGs affiliated with Thermoproteus, Sulfolobales, Pyrobaculum, and Acidilobaceae, expanding the genomic repertoire of putative hydrolytic functions in thermophilic archaea. Sequence-based thermostability prediction identified proteins with estimated melting temperatures exceeding 80 °C, with the highest predicted value reaching 87.6 °C. Collectively, these results expand current knowledge of microbial diversity and functional potential in high-altitude geothermal ecosystems and identify El Tatio as a rich source of putative hydrolase-encoding genes for future biochemical and biotechnological exploration.