Data_Sheet_6_Diversity of Lysis-Resistant Bacteria and Archaea in the Polyextreme Environment of Salar de Huasco.PDF

The production of specialized resting cells is a remarkable strategy developed by several organisms to survive unfavorable environmental conditions. Spores are specialized resting cells that are characterized by low to absent metabolic activity and higher resistance. Spore-like cells are known from multiple groups of bacteria, which can form spores under suboptimal growth conditions (e.g., starvation). In contrast, little is known about the production of specialized resting cells in archaea. In this study, we applied a culture-independent method that uses physical and chemical lysis, to assess the diversity of lysis-resistant bacteria and archaea and compare it to the overall prokaryotic diversity (direct DNA extraction). The diversity of lysis-resistant cells was studied in the polyextreme environment of the Salar de Huasco. The Salar de Huasco is a high-altitude athalassohaline wetland in the Chilean Altiplano. Previous studies have shown a high diversity of bacteria and archaea in the Salar de Huasco, but the diversity of lysis-resistant microorganisms has never been investigated. The underlying hypothesis was that the combination of extreme abiotic conditions might favor the production of specialized resting cells. Samples were collected from sediment cores along a saline gradient and microbial mats were collected in small surrounding ponds. A significantly different diversity and composition were found in the sediment cores or microbial mats. Furthermore, our results show a high diversity of lysis-resistant cells not only in bacteria but also in archaea. The bacterial lysis-resistant fraction was distinct in comparison to the overall community. Also, the ability to survive the lysis-resistant treatment was restricted to a few groups, including known spore-forming phyla such as Firmicutes and Actinobacteria. In contrast to bacteria, lysis resistance was widely spread in archaea, hinting at a generalized resistance to lysis, which is at least comparable to the resistance of dormant cells in bacteria. The enrichment of Natrinema and Halarchaeum in the lysis-resistant fraction could hint at the production of cyst-like cells or other resistant cells. These results can guide future studies aiming to isolate and broaden the characterization of lysis-resistant archaea.

多种生物为适应恶劣的生态环境，发展出一种显著的战略，即生产特殊休眠细胞。这些特殊休眠细胞，即孢子，以其代谢活动低至无以及较高的抗性为特征。孢子状细胞在多种细菌群体中均有发现，它们能在生长条件不佳（如饥饿）的情况下形成孢子。相较之下，关于古菌中特殊休眠细胞生产的了解甚少。在本研究中，我们采用了一种无需培养的方法，该方法利用物理和化学裂解技术，以评估裂解抗性细菌和古菌的多样性，并将其与总体原核生物多样性（直接DNA提取）进行比较。在多极端环境的萨勒德·胡阿斯科（Salar de Huasco）中，我们对裂解抗性细胞的多样性进行了研究。萨勒德·胡阿斯科是位于智利阿尔蒂普拉诺的高海拔无盐卤湿地。先前的研究表明，萨勒德·胡阿斯科中细菌和古菌的多样性很高，但裂解抗性微生物的多样性尚未得到研究。研究假设，极端的物理环境可能有利于特殊休眠细胞的产生。样品从盐度梯度沿沉积物岩心采集，并在周围小池塘中收集微生物膜。沉积物岩心或微生物膜中发现了显著不同的多样性和组成。此外，我们的结果显示，裂解抗性细胞的多样性不仅存在于细菌中，也存在于古菌中。与总体群落相比，细菌的裂解抗性部分具有明显的差异。能够耐受裂解抗性处理的仅限于少数群体，包括已知的产孢子门类，如厚壁菌门和放线菌门。与细菌不同，裂解抗性在古菌中广泛分布，这暗示了普遍的裂解抗性，至少与细菌中休眠细胞的抗性相当。裂解抗性部分中Natrinema和Halarchaeum的富集可能表明了形成囊状细胞或其他抗性细胞。这些结果可为未来旨在分离和扩大裂解抗性古菌特征的研究提供指导。（The production of specialized resting cells is a remarkable strategy developed by several organisms to survive unfavorable environmental conditions. Spores are specialized resting cells that are characterized by low to absent metabolic activity and higher resistance. Spore-like cells are known from multiple groups of bacteria, which can form spores under suboptimal growth conditions (e.g., starvation). In contrast, little is known about the production of specialized resting cells in archaea. In this study, we applied a culture-independent method that uses physical and chemical lysis, to assess the diversity of lysis-resistant bacteria and archaea and compare it to the overall prokaryotic diversity (direct DNA extraction). The diversity of lysis-resistant cells was studied in the polyextreme environment of the Salar de Huasco. The Salar de Huasco is a high-altitude athalassohaline wetland in the Chilean Altiplano. Previous studies have shown a high diversity of bacteria and archaea in the Salar de Huasco, but the diversity of lysis-resistant microorganisms has never been investigated. The underlying hypothesis was that the combination of extreme abiotic conditions might favor the production of specialized resting cells. Samples were collected from sediment cores along a saline gradient and microbial mats were collected in small surrounding ponds. A significantly different diversity and composition were found in the sediment cores or microbial mats. Furthermore, our results show a high diversity of lysis-resistant cells not only in bacteria but also in archaea. The bacterial lysis-resistant fraction was distinct in comparison to the overall community. Also, the ability to survive the lysis-resistant treatment was restricted to a few groups, including known spore-forming phyla such as Firmicutes and Actinobacteria. In contrast to bacteria, lysis resistance was widely spread in archaea, hinting at a generalized resistance to lysis, which is at least comparable to the resistance of dormant cells in bacteria. The enrichment of Natrinema and Halarchaeum in the lysis-resistant fraction could hint at the production of cyst-like cells or other resistant cells. These results can guide future studies aiming to isolate and broaden the characterization of lysis-resistant archaea.）