Chiapusio Geneviève, Jassey Vincent E J, Bellvert Floriant, Comte Gilles, Weston Leslie A, Delarue Frederic, Buttler Alexandre, Toussaint Marie Laure, Binet Philippe
Laboratoire ChronoEnvironnement, UMR CNRS 6249 USC INRA, Université de Bourgogne-Franche Comté, 25 211, Montbéliard Cedex, France.
Laboratoire CARRTEL, INRA 042, Alpine Centre for Research on Lake Ecosystems and Food Webs, Université Savoie Mont Blanc, 73 376, Le Bourget du Lac cedex, France.
J Chem Ecol. 2018 Dec;44(12):1146-1157. doi: 10.1007/s10886-018-1023-4. Epub 2018 Oct 8.
Sphagnum mosses mediate long-term carbon accumulation in peatlands. Given their functional role as keystone species, it is important to consider their responses to ecological gradients and environmental changes through the production of phenolics. We compared the extent to which Sphagnum phenolic production was dependent on species, microhabitats and season, and how surrounding dwarf shrubs responded to Sphagnum phenolics. We evaluated the phenolic profiles of aqueous extracts of Sphagnum fallax and Sphagnum magellanicum over a 6-month period in two microhabitats (wet lawns versus dry hummocks) in a French peatland. Phenolic profiles of water-soluble extracts were measured by UHPLC-QTOF-MS. Andromeda polifolia mycorrhizal colonization was quantified by assessing the intensity of global root cortex colonization. Phenolic profiles of both Sphagnum mosses were species-, season- and microhabitat- dependant. Sphagnum-derived acids were the phenolics mostly recovered; relative quantities were 2.5-fold higher in S. fallax than in S. magellanicum. Microtopography and vascular plant cover strongly influenced phenolic profiles, especially for minor metabolites present in low abundance. Higher mycorrhizal colonization of A. polifolia was found in lawns as compared to hummocks. Mycorrhizal abundance, in contrast to environmental parameters, was correlated with production of minor phenolics in S. fallax. Our results highlight the close interaction between mycorrhizae such as those colonizing A. polifolia and the release of Sphagnum phenolic metabolites and suggest that Sphagnum-derived acids and minor phenolics play different roles in this interaction. This work provides new insight into the ecological role of Sphagnum phenolics by proposing a strong association with mycorrhizal colonization of shrubs.
泥炭藓介导泥炭地的长期碳积累。鉴于其作为关键物种的功能作用，通过酚类物质的产生来考虑它们对生态梯度和环境变化的响应非常重要。我们比较了泥炭藓酚类物质产生在多大程度上取决于物种、微生境和季节，以及周围的矮灌木对泥炭藓酚类物质的反应。我们在法国泥炭地的两个微生境（湿草坪与干丘）中，对6个月内的柔叶泥炭藓和麦氏泥炭藓水提取物的酚类特征进行了评估。通过超高效液相色谱-四极杆飞行时间质谱法测量水溶性提取物的酚类特征。通过评估全球根皮层定殖强度来量化北极果的菌根定殖情况。两种泥炭藓的酚类特征均取决于物种、季节和微生境。泥炭藓衍生的酸是最常回收的酚类物质；柔叶泥炭藓中的相对含量比麦氏泥炭藓高2.5倍。微地形和维管植物覆盖强烈影响酚类特征，尤其是对于低丰度存在的次要代谢物。与丘相比，在草坪中发现北极果的菌根定殖率更高。与环境参数相反，菌根丰度与柔叶泥炭藓中次要酚类物质的产生相关。我们的结果强调了定殖在北极果上的菌根与泥炭藓酚类代谢产物释放之间的密切相互作用，并表明泥炭藓衍生的酸和次要酚类物质在这种相互作用中发挥不同作用。这项工作通过提出与灌木菌根定殖的强烈关联，为泥炭藓酚类物质的生态作用提供了新的见解。
