Lamit Louis J, Romanowicz Karl J, Potvin Lynette R, Rivers Adam R, Singh Kanwar, Lennon Jay T, Tringe Susannah G, Kane Evan S, Lilleskov Erik A
School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931, USA.
School of Natural Resources & Environment, University of Michigan, Ann Arbor, MI 48109, USA.
FEMS Microbiol Ecol. 2017 Jul 1;93(7). doi: 10.1093/femsec/fix082.
Peatlands store an immense pool of soil carbon vulnerable to microbial oxidation due to drought and intentional draining. We used amplicon sequencing and quantitative PCR to (i) examine how fungi are influenced by depth in the peat profile, water table and plant functional group at the onset of a multiyear mesocosm experiment, and (ii) test if fungi are correlated with abiotic variables of peat and pore water. We hypothesized that each factor influenced fungi, but that depth would have the strongest effect early in the experiment. We found that (i) communities were strongly depth stratified; fungi were four times more abundant in the upper (10-20 cm) than the lower (30-40 cm) depth, and dominance shifted from ericoid mycorrhizal fungi to saprotrophs and endophytes with increasing depth; (ii) the influence of plant functional group was depth dependent, with Ericaceae structuring the community in the upper peat only; (iii) water table had minor influences; and (iv) communities strongly covaried with abiotic variables, including indices of peat and pore water carbon quality. Our results highlight the importance of vertical stratification to peatland fungi, and the depth dependency of plant functional group effects, which must be considered when elucidating the role of fungi in peatland carbon dynamics.
泥炭地储存着大量的土壤碳，由于干旱和人为排水，这些碳易受微生物氧化作用的影响。在一项多年期的中宇宙实验开始时，我们使用扩增子测序和定量聚合酶链反应来：（i）研究真菌如何受到泥炭剖面深度、地下水位和植物功能群的影响；（ii）测试真菌是否与泥炭和孔隙水的非生物变量相关。我们假设每个因素都会影响真菌，但在实验早期深度的影响最为显著。我们发现：（i）群落具有强烈的深度分层现象；上层（10 - 20厘米）的真菌丰度是下层（30 - 40厘米）的四倍，并且随着深度增加，优势真菌从石楠类菌根真菌转变为腐生菌和内生菌；（ii）植物功能群的影响取决于深度，只有石楠科植物在上层泥炭中构建群落结构；（iii）地下水位影响较小；（iv）群落与非生物变量密切相关，包括泥炭和孔隙水碳质量指标。我们的研究结果突出了垂直分层对泥炭地真菌的重要性，以及植物功能群效应的深度依赖性，在阐明真菌在泥炭地碳动态中的作用时必须考虑这些因素。
