The mid-domain effect in ectomycorrhizal fungi: range overlap along an elevation gradient on Mount Fuji, Japan
The mid-domain effect in ectomycorrhizal fungi: range overlap along an elevation gradient on Mount Fuji, Japan
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DOI：
10.1038/ismej.2014.34
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发表时间：
2014-08-01
期刊：
影响因子：
11
通讯作者：
Nara, Kazuhide
中科院分区：
文献类型：
--
作者：
Miyamoto, Yumiko;Nakano, Takashi;Nara, Kazuhide
中域效应 (MDE) 模型预测，物种分布范围在有界地理区域内的随机放置会导致有界区域中心的范围重叠和物种丰富度增加。这些模型经常用于研究大型生物的物种丰富度模式，但与微生物相关的 MDE 却知之甚少。在这项研究中，我们研究了外生菌根（EM）真菌丰富度模式中的 MDE 特征，外生菌根真菌是生态上重要的土壤共生体群体。我们进行了密集的土壤采样，以调查日本富士山沿海拔梯度的四个温带森林中物种范围的重叠以及 MDE 对 EM 真菌的适用性。使用直接测序进行的分子分析揭示了 302 种 EM 真菌物种。在多个林分中发现的 73 种 EM 真菌中，有 72 种沿着海拔梯度栖息在连续范围内。物种范围的最大重叠和最高的物种丰富度发生在梯度中间的海拔处。观察到的丰富度模式也符合中域零模型的 95% 置信区间，支持 MDE 在 EM 真菌丰富度中的作用。观测到的丰富度与中域零值估计平均值的偏差与一些环境因素（包括降水和土壤 C/N）负相关，表明无法解释的丰富度模式可能是由这些环境因素驱动的。我们的结果清楚地支持微生物物种范围沿环境梯度的存在以及 MDE 的潜在适用性，以更好地了解微生物多样性模式。
Mid-domain effect (MDE) models predict that the random placement of species' ranges within a bounded geographical area leads to increased range overlap and species richness in the center of the bounded area. These models are frequently applied to study species-richness patterns of macroorganisms, but the MDE in relation to microorganisms is poorly understood. In this study, we examined the characteristics of the MDE in richness patterns of ectomycorrhizal (EM) fungi, an ecologically important group of soil symbionts. We conducted intensive soil sampling to investigate overlap among species ranges and the applicability of the MDE to EM fungi in four temperate forest stands along an elevation gradient on Mount Fuji, Japan. Molecular analyses using direct sequencing revealed 302 EM fungal species. Of 73 EM fungal species found in multiple stands, 72 inhabited a continuous range along the elevation gradient. The maximum overlap in species range and the highest species richness occurred at elevations in the middle of the gradient. The observed richness pattern also fit within the 95% confidence interval of the mid-domain null model, supporting the role of the MDE in EM fungal richness. Deviation in observed richness from the mean of the mid-domain null estimation was negatively correlated with some environmental factors, including precipitation and soil C/N, indicating that unexplained richness patterns could be driven by these environmental factors. Our results clearly support the existence of microbial species' ranges along environmental gradients and the potential applicability of the MDE to better understand microbial diversity patterns.