Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Université de Lorraine, UMR 7360, Campus Bridoux rue du Général Delestraint, 57070, Metz, France; LIEC, CNRS, UMR 7360, 57070, Metz, France.
Environ Microbiol. 2014 Jul;16(7):2145-56. doi: 10.1111/1462-2920.12245. Epub 2013 Sep 3.
We combined microscopic and molecular methods to investigate fungal assemblages on alder leaf litter exposed in the benthic and hyporheic zones of five streams across a gradient of increasing acidification for 4 weeks. The results showed that acidification and elevated Al concentrations strongly depressed sporulating aquatic hyphomycetes diversity in both zones of streams, while fungal diversity assessed by denaturing gradient gel electrophoresis (DGGE) appeared unaffected. Clone library analyses revealed that fungal communities on leaves were dominated by members of Ascomycetes and to a lesser extent by Basidiomycetes and Chytridiomycetes. An important contribution of terrestrial fungi was observed in both zones of the most acidified stream and in the hyporheic zone of the reference circumneutral stream. The highest leaf breakdown rate was observed in the circumneutral stream and occurred in the presence of both the highest diversity of sporulating aquatic hyphomycetes and the highest contribution to clone libraries of sequences affiliated with aquatic hyphomycetes. Both methods underline the major role played by aquatic hyphomycetes in leaf decomposition process. Our findings also bring out new highlights on the identity of leaf-associated fungal communities and their responses to anthropogenic alteration of running water ecosystems.
我们结合微观和分子方法，研究了在 5 条溪流的底部和底层区域暴露于落叶中的真菌组合，这些溪流的酸化程度逐渐增加，持续了 4 周。结果表明，酸化和升高的 Al 浓度强烈抑制了两个区域溪流中孢子形成水生丝孢菌的多样性，而通过变性梯度凝胶电泳 (DGGE) 评估的真菌多样性似乎没有受到影响。克隆文库分析表明，叶片上的真菌群落主要由子囊菌门成员组成，其次是担子菌门和壶菌门成员。在最酸化的溪流的两个区域以及参考中性溪流的底层区域都观察到了陆地真菌的重要贡献。在中性溪流中观察到的叶片分解率最高，并且在存在最高多样性的孢子形成水生丝孢菌和对水生丝孢菌序列的克隆文库的最大贡献的情况下发生。这两种方法都强调了水生丝孢菌在叶片分解过程中所起的主要作用。我们的研究结果还揭示了与叶片相关的真菌群落的身份及其对流水生态系统人为改变的响应的新亮点。
