Sand dunes of the Mediterranean region constitute drought-stressed, low-fertility ecosystems. Arbuscular mycorrhizal fungi (AMF) are regarded as key components of their biota, that contribute to plant host adaptation and fitness. However, AMF community assembly rules in the roots of the psammophilous plants of coastal sand dunes have not been investigated. We studied the root colonizing AMF communities of four characteristic native plants of eastern Mediterranean coastal foredunes, in nine locations in Greece. Host specificity (plant identity) was the major driver of AMF community assembly in the plant roots, while geographical distance between locations was not related to differences in the AMF communities. Additionally, colonizer AMF communities were characterized by overdominance of a single OTU which was remarkably host-specific among locations. Wider dissimilarity in AMF communities was observed in small and disturbed (SD) sites compared to large and undisturbed (LU) sites, a trait that may be attributed to relaxed environmental filtering and facilitated AMF dispersal/immigration in SD sites from surrounding habitats. Overall, our results indicate that the assembly of root-colonizing AMF communities in the eastern Mediterranean sand dunes is characterized by strong biotic filtering (host identity), suggesting that co-adaptation processes may be more pronounced than previously proposed, under extreme environmental conditions.

中文翻译：

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地中海地区沿海沙丘植物丛枝菌根真菌根定殖者的强宿主特异性选择和过度优势

地中海地区的沙丘构成了干旱、低肥力的生态系统。丛枝菌根真菌（AMF）被认为是其生物群的关键组成部分，有助于植物宿主的适应和适应性。然而，尚未研究沿海沙丘沙丘植物根系中的AMF群落组装规则。我们研究了位于希腊九个地点的地中海东部沿海前缘植物的四种特色本土植物的 AMF 群落的根定殖。宿主特异性（植物特性）是植物根部 AMF 群落组装的主要驱动力，而位置之间的地理距离与 AMF 群落的差异无关。此外，殖民者 AMF 社区的特点是单个 OTU 占主导地位，该 OTU 在不同地点之间具有显着的宿主特异性。与大型和未受干扰 (LU) 站点相比，在小型和受干扰 (SD) 站点中观察到 AMF 群落的更广泛差异，这一特征可能归因于宽松的环境过滤并促进了 AMF 从周围栖息地在 SD 站点中的扩散/迁移。总体而言，我们的结果表明，在地中海东部沙丘中，根定殖 AMF 群落的组装具有强大的生物过滤（宿主身份）的特征，这表明在极端环境条件下，共同适应过程可能比以前提出的更为明显。一种可能归因于环境过滤放松和促进 AMF 从周围栖息地向 SD 站点扩散/迁移的特征。总体而言，我们的结果表明，在地中海东部沙丘中，根定殖 AMF 群落的组装具有强大的生物过滤（宿主身份）的特征，这表明在极端环境条件下，共同适应过程可能比以前提出的更为明显。一种可能归因于环境过滤放松和促进 AMF 从周围栖息地向 SD 站点扩散/迁移的特征。总体而言，我们的结果表明，在地中海东部沙丘中，根定殖 AMF 群落的组装具有强大的生物过滤（宿主身份）的特征，这表明在极端环境条件下，共同适应过程可能比以前提出的更为明显。