Department of Ecological and Biological Sciences, University of Tuscia , Largo dell'Università snc, 01100, Viterbo, Italy.
Department of Microbiology and Plant Pathology, University of California, 900 University Ave , Riverside, California 92521.
Mycologia. 2021 Jan-Feb;113(1):108-133. doi: 10.1080/00275514.2020.1816761. Epub 2020 Nov 24.
In an era of rapid climate change and expansion of desertification, the extremely harsh conditions of drylands are a true challenge for microbial life. Under drought conditions, where most life forms cannot survive, rocks represent the main refuge for life. Indeed, the endolithic habitat provides thermal buffering, physical stability, and protection against incident ultraviolet (UV) radiation and solar radiation and, to some extent, ensures water retention to microorganisms. The study of these highly specialized extreme-tolerant and extremophiles may provide tools for understanding microbial interactions and processes that allow them to keep their metabolic machinery active under conditions of dryness and oligotrophy that are typically incompatible with active life, up to the dry limits for life. Despite lithobiontic communities being studied all over the world, a comprehensive understanding of their ecology, evolution, and adaptation is still nascent. Herein, we survey the fungal component of these microbial ecosystems. We first provide an overview of the main defined groups (i.e., lichen-forming fungi, black fungi, and yeasts) of the most known and studied Antarctic endolithic communities that are almost the only life forms ensuring ecosystem functionality in the ice-free areas of the continent. For each group, we discuss their main traits and their diversity. Then, we focus on the fungal taxonomy and ecology of other worldwide endolithic communities. Finally, we highlight the utmost importance of a global rock survey in order to have a comprehensive view of the diversity, distribution, and functionality of these fungi in drylands, to obtain tools in desert area management, and as early alarm systems to climate change.
在气候变化和沙漠化扩张的时代，干旱地区极其恶劣的条件对微生物生命来说是一个真正的挑战。在干旱条件下，大多数生命形式都无法生存，而岩石则是生命的主要避难所。事实上，内生栖息地提供了热缓冲、物理稳定性，并能抵御入射的紫外线（UV）辐射和太阳辐射，在一定程度上还能保持微生物的水分。对这些高度专业化的耐极端和极端微生物的研究，可能为理解微生物的相互作用和过程提供工具，这些微生物在干旱和贫营养条件下，其新陈代谢机制仍能保持活跃，而这些条件通常与活跃的生命不相容，甚至达到生命的干燥极限。尽管世界各地都在研究石生生物群落，但对其生态、进化和适应的全面了解仍处于起步阶段。在此，我们调查了这些微生物生态系统中的真菌组成部分。我们首先概述了在南极洲无冰区中，保证生态系统功能的几乎唯一生命形式——最知名和研究最多的南极内生群落中的主要真菌群（即地衣形成真菌、黑真菌和酵母）。对于每个群组，我们讨论了它们的主要特征和多样性。然后，我们聚焦于其他世界内生群落的真菌分类学和生态学。最后，我们强调了进行全球岩石调查的极端重要性，以便全面了解这些干旱地区内生真菌的多样性、分布和功能，为沙漠地区管理提供工具，并作为气候变化的早期预警系统。
