Straková Dáša, Sánchez-Porro Cristina, de la Haba Rafael R, Ventosa Antonio
Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, 41012 Sevilla, Spain.
Microorganisms. 2025 Mar 27;13(4):761. doi: 10.3390/microorganisms13040761.
Haloarchaea, a group of extremophilic archaea, thrive in hypersaline environments characterized not only by high salinity but also by other extreme conditions, such as intense UV radiation, high osmotic pressure, heavy metal contamination, oxidative stress, and fluctuating temperatures. This study investigates the environmental adaptation strategies of species of two genera, and , the second and third largest haloarchaeal genera, respectively, after . Comparative genomic analyses were conducted on 48 species from both genera to elucidate their genomic diversity, metabolic potential, and stress-tolerance mechanisms. The genomes revealed diverse metabolic pathways, including rhodopsin-mediated phototrophy, nitrogen assimilation, and thiamine biosynthesis, which support their survival and adaptation to extreme conditions. The analysis identified mechanisms for oxidative stress mitigation, DNA repair, "salt-in" and "salt-out" osmoregulatory strategies, adaptations to temperature shifts and heavy metal exposure, and immune defense. Experimental validation of four representative species, S1AR25-5A, S1CR25-12, S3CR25-11, and S1CR25-10, isolated from the heavy-metal-rich hypersaline soils in the Odiel Saltmarshes (Huelva, Spain), demonstrated their tolerance, especially to arsenic, corroborating genomic predictions. This study advances our understanding of the resilience of haloarchaea under poly-extreme conditions and underscores their ecological significance and promise for biotechnological applications, such as the bioremediation of heavy-metal-polluted environments and the production of valuable biomolecules.
嗜盐古菌是一类极端嗜盐古菌，在高盐环境中茁壮成长，这种环境不仅具有高盐度，还具有其他极端条件，如强烈的紫外线辐射、高渗透压、重金属污染、氧化应激和温度波动。本研究调查了两个属（分别是继之后的第二和第三大嗜盐古菌属）的物种的环境适应策略。对这两个属的48个物种进行了比较基因组分析，以阐明它们的基因组多样性、代谢潜力和应激耐受机制。基因组揭示了多种代谢途径，包括视紫红质介导的光养作用、氮同化和硫胺素生物合成，这些支持了它们在极端条件下的生存和适应。分析确定了减轻氧化应激、DNA修复、“盐进”和“盐出”渗透调节策略、适应温度变化和重金属暴露以及免疫防御的机制。从西班牙韦尔瓦省奥迪尔盐沼富含重金属的高盐土壤中分离出的四个代表性物种（S1AR25 - 5A、S1CR25 - 12、S3CR25 - 11和S1CR25 - 10）的实验验证表明了它们的耐受性，尤其是对砷的耐受性，证实了基因组预测。本研究增进了我们对嗜盐古菌在多极端条件下恢复力的理解，并强调了它们的生态意义以及在生物技术应用方面的前景，如重金属污染环境的生物修复和有价值生物分子的生产。
