The ice-free McMurdo Dry Valleys of Antarctica are dominated by nutrient-poor mineral soil and rocky outcrops. The principal habitat for microorganisms is within rocks (endolithic). In this environment, microorganisms are provided with protection against sub-zero temperatures, rapid thermal fluctuations, extreme dryness, and ultraviolet and solar radiation. Endolithic communities include lichen, algae, fungi, and a diverse array of bacteria. Chloroflexota is among the most abundant bacterial phyla present in these communities. Among the Chloroflexota are four novel classes of bacteria, here named Candidatus Spiritibacteria class. nov. (=UBA5177), Candidatus Martimicrobia class. nov. (=UBA4733), Candidatus Tarhunnaeia class. nov. (=UBA6077), and Candidatus Uliximicrobia class. nov. (=UBA2235). We retrieved 17 high-quality metagenome-assembled genomes (MAGs) that represent these four classes. Based on genome predictions, all these bacteria are inferred to be aerobic heterotrophs that encode enzymes for the catabolism of diverse sugars. These and other organic substrates are likely derived from lichen, algae, and fungi, as metabolites (including photosynthate), cell wall components, and extracellular matrix components. The majority of MAGs encode the capacity for trace gas oxidation using high-affinity uptake hydrogenases, which could provide energy and metabolic water required for survival and persistence. Furthermore, some MAGs encode the capacity to couple the energy generated from H 2 and CO oxidation to support carbon fixation (atmospheric chemosynthesis). All encode mechanisms for the detoxification and efflux of heavy metals. Certain MAGs encode features that indicate possible interactions with other organisms, such as Tc-type toxin complexes, hemolysins, and macroglobulins.
IMPORTANCEThe ice-free McMurdo Dry Valleys of Antarctica are the coldest and most hyperarid desert on Earth. It is, therefore, the closest analog to the surface of the planet Mars. Bacteria and other microorganisms survive by inhabiting airspaces within rocks (endolithic). We identify four novel classes of phylum Chloroflexota , and, based on interrogation of 17 metagenome-assembled genomes, we predict specific metabolic and physiological adaptations that facilitate the survival of these bacteria in this harsh environment\uffe2\uff80\uff94including oxidation of trace gases and the utilization of nutrients (including sugars) derived from lichen, algae, and fungi. We propose that such adaptations allow these endolithic bacteria to eke out an existence in this cold and extremely dry habitat.
", "keywords": ["570", "Bacteria", "Fungi", "Antarctic Regions", "Chloroflexi", "15. Life on land", "Survival strategies", "Cold Temperature", "Extremophiles", "13. Climate action", "Antarctica", "Endolithic communities", "Metagenomics", "14. Life underwater", "Sugars", "Settore BIO/19 - MICROBIOLOGIA GENERALE"]}, "links": [{"href": "https://doi.org/10449/84316"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Applied%20and%20Environmental%20Microbiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10449/84316", "name": "item", "description": "10449/84316", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10449/84316"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2024-02-19T00:00:00Z"}}, {"id": "10.1093/treephys/tps133", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-21T16:17:19Z", "type": "Journal Article", "created": "2013-02-01", "title": "Nitrogen Nutrition And Drought Hardening Exert Opposite Effects On The Stress Tolerance Of Pinus Pinea L. Seedlings", "description": "Functional attributes determine the survival and growth of planted seedlings in reforestation projects. Nitrogen (N) and water are important resources in the cultivation of forest species, which have a strong effect on plant functional traits. We analyzed the influence of N nutrition on drought acclimation of Pinus pinea L. seedlings. Specifically, we addressed if high N fertilization reduces drought and frost tolerance of seedlings and whether drought hardening reverses the effect of high N fertilization on stress tolerance. Seedlings were grown under two N fertilization regimes (6 and 100 mg N per plant) and subjected to three drought-hardening levels (well-watered, moderate and strong hardening). Water relations, gas exchange, frost damage, N concentration and growth at the end of the drought-hardening period, and survival and growth of seedlings under controlled xeric and mesic outplanting conditions were measured. Relative to low-N plants, high-N plants were larger, had higher stomatal conductance (27%), residual transpiration (11%) and new root growth capacity and closed stomata at higher water potential. However, high N fertilization also increased frost damage (24%) and decreased plasmalemma stability to dehydration (9%). Drought hardening reversed to a great extent the reduction in stress tolerance caused by high N fertilization as it decreased frost damage, stomatal conductance and residual transpiration by 21, 31 and 24%, respectively, and increased plasmalemma stability to dehydration (8%). Drought hardening increased tissue non-structural carbohydrates and N concentration, especially in high-fertilized plants. Frost damage was positively related to the stability of plasmalemma to dehydration (r\u2009=\u20090.92) and both traits were negatively related to the concentration of reducing soluble sugars. No differences existed between moderate and strong drought-hardening treatments. Neither N nutrition nor drought hardening had any clear effect on seedling performance under xeric outplanting conditions. However, fertilization increased growth under mesic conditions, whereas drought hardening decreased growth. We conclude that drought hardening and N fertilization applied under typical container nursery operational conditions exert opposite effects on the physiological stress tolerance of P. pinea seedlings. While drought hardening increases overall stress tolerance, N nutrition reduces it and yet has no effect on the drought acclimation capacity of seedlings.", "keywords": ["0106 biological sciences", "2. Zero hunger", "Nitrogen", "Acclimatization", "Water", "Plant Transpiration", "15. Life on land", "Pinus", "Plant Roots", "01 natural sciences", "6. Clean water", "Droughts", "Trees", "Cold Temperature", "Plant Leaves", "Seedlings", "Stress", " Physiological", "Plant Stomata", "Photosynthesis", "Fertilizers", "Plant Shoots"]}, "links": [{"href": "https://doi.org/10.1093/treephys/tps133"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Tree%20Physiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1093/treephys/tps133", "name": "item", "description": "10.1093/treephys/tps133", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1093/treephys/tps133"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2013-01-30T00:00:00Z"}}, {"id": "10.1128/aem.02264-23", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-21T16:17:59Z", "type": "Journal Article", "created": "2024-02-19", "title": "Novel endolithic bacteria of phylum Chloroflexota reveal a myriad of potential survival strategies in the Antarctic desert", "description": "ABSTRACTThe ice-free McMurdo Dry Valleys of Antarctica are dominated by nutrient-poor mineral soil and rocky outcrops. The principal habitat for microorganisms is within rocks (endolithic). In this environment, microorganisms are provided with protection against sub-zero temperatures, rapid thermal fluctuations, extreme dryness, and ultraviolet and solar radiation. Endolithic communities include lichen, algae, fungi, and a diverse array of bacteria. Chloroflexota is among the most abundant bacterial phyla present in these communities. Among the Chloroflexota are four novel classes of bacteria, here named Candidatus Spiritibacteria class. nov. (=UBA5177), Candidatus Martimicrobia class. nov. (=UBA4733), Candidatus Tarhunnaeia class. nov. (=UBA6077), and Candidatus Uliximicrobia class. nov. (=UBA2235). We retrieved 17 high-quality metagenome-assembled genomes (MAGs) that represent these four classes. Based on genome predictions, all these bacteria are inferred to be aerobic heterotrophs that encode enzymes for the catabolism of diverse sugars. These and other organic substrates are likely derived from lichen, algae, and fungi, as metabolites (including photosynthate), cell wall components, and extracellular matrix components. The majority of MAGs encode the capacity for trace gas oxidation using high-affinity uptake hydrogenases, which could provide energy and metabolic water required for survival and persistence. Furthermore, some MAGs encode the capacity to couple the energy generated from H 2 and CO oxidation to support carbon fixation (atmospheric chemosynthesis). All encode mechanisms for the detoxification and efflux of heavy metals. Certain MAGs encode features that indicate possible interactions with other organisms, such as Tc-type toxin complexes, hemolysins, and macroglobulins.
IMPORTANCEThe ice-free McMurdo Dry Valleys of Antarctica are the coldest and most hyperarid desert on Earth. It is, therefore, the closest analog to the surface of the planet Mars. Bacteria and other microorganisms survive by inhabiting airspaces within rocks (endolithic). We identify four novel classes of phylum Chloroflexota , and, based on interrogation of 17 metagenome-assembled genomes, we predict specific metabolic and physiological adaptations that facilitate the survival of these bacteria in this harsh environment\uffe2\uff80\uff94including oxidation of trace gases and the utilization of nutrients (including sugars) derived from lichen, algae, and fungi. We propose that such adaptations allow these endolithic bacteria to eke out an existence in this cold and extremely dry habitat.
", "keywords": ["570", "Bacteria", "Fungi", "Antarctic Regions", "Chloroflexi", "15. Life on land", "Survival strategies", "Cold Temperature", "Extremophiles", "13. Climate action", "Antarctica", "Endolithic communities", "Metagenomics", "14. Life underwater", "Sugars", "Settore BIO/19 - MICROBIOLOGIA GENERALE"]}, "links": [{"href": "https://doi.org/10.1128/aem.02264-23"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Applied%20and%20Environmental%20Microbiology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1128/aem.02264-23", "name": "item", "description": "10.1128/aem.02264-23", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1128/aem.02264-23"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2024-02-19T00:00:00Z"}}, {"id": "10.2134/jeq2006.0205", "type": "Feature", "geometry": null, "properties": {"license": "Closed Access", "updated": "2026-09-21T16:18:50Z", "type": "Journal Article", "created": "2007-01-11", "description": "ABSTRACTIn the Red River Valley of the upper midwestern United States, soil temperatures often remain below freezing during winter and N2O emissions from frozen cropland soils is assumed to be negligible. This study was conducted to determine the strength of N2O emissions and denitrification when soil temperatures were below zero for a manure\uffe2\uff80\uff90amended, certified organic field (T2O) compared with an unamended, conventionally managed field (T2C). Before manure application, both fields were similar with respect to autotrophic and heterotrophic N2O production and N2O flux at the soil surface (0.15 \uffc2\uffb1 0.05 mg N2O\uffe2\uff80\uff93N m\uffe2\uff88\uff922 d\uffe2\uff88\uff921 for T2O and 0.12 \uffc2\uffb1 0.06 mg N2O\uffe2\uff80\uff93N m\uffe2\uff88\uff922 d\uffe2\uff88\uff921 for T2C). After application of pelletized, dehydrated manure, average daily flux (based on time\uffe2\uff80\uff90integrated fluxes from 20 November to 8 April), was 1.19 \uffc2\uffb1 0.34 mg N2O\uffe2\uff80\uff93N m\uffe2\uff88\uff922 d\uffe2\uff88\uff921 for T2O and 0.47 \uffc2\uffb1 0.37 mg N2O\uffe2\uff80\uff93N m\uffe2\uff88\uff922 d\uffe2\uff88\uff921 for T2C. Denitrification for intact cores measured in the laboratory at \uffe2\uff88\uff922.5\uffc2\uffb0C was greater for organically managed soils, although only marginally significant (p < 0.1). Cumulative emissions for all winter measurements (from 16 November to 8 April) averaged 1.63 kg N2O\uffe2\uff80\uff93N ha\uffe2\uff88\uff921 for T2O and 0.64 kg N2O\uffe2\uff80\uff93N ha\uffe2\uff88\uff921 for T2C. Biological N2O production was evident at sub\uffe2\uff80\uff90zero soil temperatures, with winter emissions exceeding those measured in late summer. Late autumn manure application enhanced cumulative N2O\uffe2\uff80\uff93N emissions by 0.9 kg ha\uffe2\uff88\uff921
", "keywords": ["Cold Temperature", "2. Zero hunger", "Soil", "13. Climate action", "Nitrous Oxide", "0401 agriculture", " forestry", " and fisheries", "Agriculture", "04 agricultural and veterinary sciences", "15. Life on land", "6. Clean water"], "contacts": [{"organization": "Rebecca L. Phillips", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.2134/jeq2006.0205"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Journal%20of%20Environmental%20Quality", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.2134/jeq2006.0205", "name": "item", "description": "10.2134/jeq2006.0205", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.2134/jeq2006.0205"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2007-01-01T00:00:00Z"}}, {"id": "PMC4529868", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-21T16:24:40Z", "type": "Journal Article", "created": "2015-06-29", "title": "Characterization of CCT\u03b1 and evaluating its expression in the mud crab Scylla paramamosain when challenged by low temperatures alone and in combination with high and low salinity", "description": "Chaperonin containing the T-complex polypeptide-1 (CCT), which is known to be involved in intracellular assembly and folding of proteins, is a class of chaperonin omnipresent in all forms of life. Previous studies showed that CCT played a vital role in cold hardiness of various animals. In order to understand the response of the polypeptide complex to low temperature challenge and other environmental stresses, a subunit of CCT (CCT\u03b1) was cloned from the mud crab Scylla paramamosain by expressed sequence tag (EST) analysis and rapid amplification of cDNA ends (RACE). The full-length cDNA SpCCT\u03b1 was of 1972 bp and contained a 1668 bp open reading frame (ORF) encoding a polypeptide of 555 amino acids with four conserved motifs. The messenger ribonucleic acid (mRNA) levels of SpCCT\u03b1 in ten tissues of adult S. paramamosain was subsequently examined and the highest expression was found in muscle, followed by gill, hepatopancreas, thoracic ganglion, hemocyte, heart, cerebral ganglion, stomach, eyestalk ganglion, and epidermis. The expressions of SpCCT\u03b1 in the muscle of sub-adult crabs (pre-acclimated to 28 \u00b0C) subjected to the challenges of both lower temperatures (25, 20, 15, and 10 \u00b0C) alone and low temperatures (15 and 10 \u00b0C) in combination with salinity of 35 and 10 were further investigated by fluorescent quantitative real-time PCR (qPCR). It was revealed that when exposed to lower temperatures alone, the mRNA transcripts of the SpCCT\u03b1 gene in the muscle were generally induced for significant higher expression at 10 \u00b0C treatment than the 25, 20, and 15 \u00b0C treatments; meanwhile, exposure to 15 \u00b0C also frequently led to significantly higher expression than those at 20 and 25 \u00b0C. This finding indicated that the up-regulation of SpCCT\u03b1 was closely related to the cold hardiness of S. paramamosain. The results of an additional experiment challenging the sub-adult crabs with various combinations of low temperatures with different salinity conditions generally demonstrated that at both 10 and 15 \u00b0C, the expression of SpCCT\u03b1 under the high salinity of 35 was significantly lower than that at low salinity of 10, implying that the damages caused by low temperatures with high salinity were less than that under low salinity.", "keywords": ["Cold Temperature", "0301 basic medicine", "Salinity", "03 medical and health sciences", "Crustacea", "Animals", "Salt Tolerance", "Real-Time Polymerase Chain Reaction", "Chaperonin Containing TCP-1"], "contacts": [{"organization": "Yu, Kun, Gong, Jie, Huang, Chencui, Huang, Huiyang, Ye, Haihui, Wang, Guizhong, Zeng, Chaoshu,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/PMC4529868"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Cell%20Stress%20and%20Chaperones", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "PMC4529868", "name": "item", "description": "PMC4529868", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/PMC4529868"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2015-09-01T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Cold+Temperature&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Cold+Temperature&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Cold+Temperature&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Cold+Temperature&offset=5", "hreflang": "en-US"}], "numberMatched": 5, "numberReturned": 5, "distributedFeatures": [], "timeStamp": "2026-09-22T12:51:04.836120Z"}