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

<b>Abstract</b><br/>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.

<b>摘要</b><br/>当前对外生菌根真菌（ectomycorrhizal fungal, EMF）群落结构的认知受限于分类分辨率不足与个体生态学信息匮乏。泡状须腹菌（Rhizopogon vesiculosus）与酒红须腹菌（R. vinicolor）隶属于担子菌门（Basidiomycota），二者在形态与遗传特征上亲缘关系紧密。它们是内陆花旗松（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仍未明确。本研究针对两种须腹菌的遗传株系（genet）的微生境关联与觅食策略展开了系统探究。研究对比了不同须腹菌物种之间，以及干旱与湿润土壤水分状况下的真菌遗传株系的菌丝空间分布格局、侵染范围与根系定殖模式。研究人员通过系统挖掘土壤中的菌丝，并利用微卫星DNA标记（microsatellite DNA markers）完成物种鉴定。<br/>研究结果显示，相较于酒红须腹菌，泡状须腹菌的菌丝分布深度更深、空间侵染范围更广，且定殖的树木根系数量更多。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处，在与土壤保水相关的微生境内丰度尤为突出。当生境中存在酒红须腹菌时，泡状须腹菌的分布会向矿质土壤层偏移，而酒红须腹菌在此类生境中则多呈缺失状态。这表明种间竞争与觅食策略差异可能是促成二者垂直生态位分化的关键因素。相较于干旱样地，湿润样地中泡状须腹菌与酒红须腹菌的菌丝系统平均分布深度更深、侵染范围更广。但两种遗传株系的空间连续性以及其所定殖的树木数量，在不同土壤水分状况下均无显著差异。