Data from: Vertical partitioning between sister species of Rhizopogon fungi on mesic and xeric sites in an interior Douglas-fir forest

Understanding ectomycorrhizal fungal (EMF) community structure is limited by a lack of taxonomic resolution and autecological information. Rhizopogon vesiculosus and R. vinicolor (Basidiomycota) are morphologically and genetically related species. They are dominant members of interior Douglas-fir (Pseudotsuga menziesii var. glauca) EMF communities, but mechanisms leading to their coexistence are unknown. We investigated the microsite associations and foraging strategy of individual R. vesiculosus and R. vinicolor genets. Mycelia spatial patterns, pervasiveness and root colonization patterns of fungal genets were compared between Rhizopogon species and between xeric and mesic soil moisture regimes. Rhizopogon spp. mycelia were systematically excavated from the soil and identified using microsatellite DNA markers. Rhizopogon vesiculosus mycelia occurred at greater depth, were more spatially pervasive, and colonized more tree roots than R. vinicolor mycelia. Both species were frequently encountered in organic layers and between the interface of organic and mineral horizons. They were particularly abundant within microsites associated with soil moisture retention. The occurrence of R. vesiculosus shifted in the presence of R. vinicolor towards mineral soil horizons, where R. vinicolor was mostly absent. This suggests that competition and foraging strategy may contribute towards the vertical partitioning observed between these species. R. vesiculosus and R. vinicolor mycelia systems occurred at greater mean depths and were more pervasive in mesic plots compared to xeric plots. The spatial continuity and number of trees colonized by genets of each species did not significantly differ between soil moisture regimes.

外生菌根真菌（ectomycorrhizal fungal, EMF）群落结构的解析长期受限于分类学分辨率不足与个体生态学信息匮乏。囊泡须腹菌（Rhizopogon vesiculosus）与酒红须腹菌（R. vinicolor）均隶属于担子菌门（Basidiomycota），二者在形态与遗传特征上高度相似，且同为内陆花旗松（Pseudotsuga menziesii var. glauca）外生菌根群落的优势类群，但二者共存的潜在机制迄今仍不明晰。本研究针对两种须腹菌的遗传株系，探究其微生境关联特征与觅食策略。研究比较了不同须腹菌物种间，以及干旱与湿润土壤水分条件下，真菌遗传株系的空间分布模式、菌丝蔓延广度与根系定殖特征。研究人员系统性挖掘土壤中的菌丝体，并通过微卫星DNA标记完成物种鉴定。结果显示，相较于酒红须腹菌，囊泡须腹菌的菌丝分布深度更大、空间蔓延范围更广，且定殖的林木根系数量更多。两种真菌均常见于有机土层以及有机层与矿质土层的交界面，在保水性良好的微生境中丰度尤高。当共存有酒红须腹菌时，囊泡须腹菌的分布会向矿质土层偏移，而酒红须腹菌在此类生境中则鲜有出现。这一结果表明，种间竞争与觅食策略差异可能是导致二者垂直生态位分化的重要原因。相较于干旱样地，湿润样地中两种须腹菌的菌丝系统平均分布深度更大、蔓延范围更广。但不同土壤水分条件下，两种真菌遗传株系的空间连续性与定殖林木数量均无显著差异。