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.

中文翻译：

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超越极限：岩石是旱地真菌的终极避难所

在气候快速变化和荒漠化扩大的时代，干旱地区极其恶劣的条件对微生物生命构成了真正的挑战。在干旱条件下，大多数生命形式无法生存，岩石是生命的主要避难所。事实上，石内栖息地提供了热缓冲、物理稳定性和防止入射紫外线 (UV) 辐射和太阳辐射的保护，并在某种程度上确保了微生物的保水。对这些高度特化的极端耐受和极端微生物的研究可能为理解微生物相互作用和过程提供工具，使它们能够在干燥和贫营养条件下保持活跃的代谢机制，这些条件通常与活跃生命不相容，直至生命的干燥极限. 尽管全世界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的真菌成分。我们首先概述了最知名和研究最多的南极内石群落的主要定义群体（即形成地衣的真菌、黑色真菌和酵母菌），这些群落几乎是确保南极无冰地区生态系统功能的唯一生命形式。大陆。对于每个群体，我们讨论他们的主要特征和多样性。然后，我们专注于其他世界范围内的石内群落的真菌分类学和生态学。最后，我们强调了全球岩石调查的极端重要性，以便全面了解干旱地区这些真菌的多样性、分布和功能，