Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR 5557 Ecologie Microbienne, Villeurbanne, France.
Institut Universitaire de France (IUF), Paris, France.
NPJ Biofilms Microbiomes. 2024 Nov 6;10(1):121. doi: 10.1038/s41522-024-00589-3.
Tourism in Paleolithic caves can cause an imbalance in cave microbiota and lead to cave wall alterations, such as dark zones. However, the mechanisms driving dark zone formation remain unclear. Using shotgun metagenomics in Lascaux Cave's Apse and Passage across two years, we tested metabarcoding-derived functional hypotheses regarding microbial diversity and metabolic potential in dark zones vs unmarked surfaces nearby. Taxonomic and functional metagenomic profiles were consistent across years but divergent between cave locations. Aromatic compound degradation genes were prevalent inside and outside dark zones, as expected from past biocide usage. Dark zones exhibited enhanced pigment biosynthesis potential (melanin and carotenoids) and melanin was evidenced chemically, while unmarked surfaces showed genes for antimicrobials production, suggesting that antibiosis might restrict the development of pigmented microorganisms and dark zone extension. Thus, this work revealed key functional microbial traits associated with dark zone formation, which helps understand cave alteration processes under severe anthropization.
洞穴旅游可能导致洞穴微生物群落失衡，并导致洞穴墙壁发生变化，如出现暗区。然而，导致暗区形成的机制仍不清楚。本研究使用古生物学洞穴的拱顶和通道中的鸟枪法宏基因组学，在两年内对暗区和附近未标记表面的微生物多样性和代谢潜能进行了基于代谢组学的功能假设检验。分类和功能宏基因组图谱在两年间是一致的，但在洞穴位置上存在差异。降解芳香族化合物的基因在暗区内外都很普遍，这与过去使用生物杀灭剂的情况相符。暗区表现出增强的色素生物合成潜力（黑色素和类胡萝卜素），并且黑色素在化学上得到了证实，而未标记的表面则显示出抗菌药物产生的基因，这表明抗菌作用可能限制了色素微生物的发展和暗区的扩展。因此，这项工作揭示了与暗区形成相关的关键功能微生物特征，有助于理解在严重人为化条件下的洞穴变化过程。
