The long-lived five-needle pines, Pinus flexilis (limber pine) and Pinus longaeva (Great Basin bristlecone pine) can co-occur and may form symbiotic partnerships with the same species of ectomycorrhizal fungi. These shared symbiotic relationships may facilitate the persistence of these pine species. Throughout their lives, P. flexilis and P. longaeva may also assemble unique belowground fungal communities, adding to the conservation value of ancient trees. We used MiSeq sequencing of fungal rDNA to compare fungal community similarity for co-occurring P. flexilis and P. longaeva roots and soils in an old-growth forest at the Utah Forest Dynamics Plot, Utah, USA. We cored trees to measure their age and determine whether fungal communities change with advanced tree age. We found 720 amplicon sequence variants associated with P. flexilis roots, 736 with P. longaeva roots, and 199 that were shared between the two pines. Root-associated fungal communities were significantly different between P. flexilis and P. longaeva despite similar soil communities. The fungal community composition on P. flexilis roots and around P. longaeva soil was associated with advanced tree age up to 1340 years. The root-associated fungal community of P. flexilis and the soil community of P. longaeva increased in dissimilarity with tree age, indicating that age heterogeneity within old-growth stands promotes fungal diversity. The significant differences in root-associated fungal communities between the two pine species highlights that they are likely engaged in different bi-directional selection with fungal communities.

长寿命的五针松，柔松（Pinus flexilis）（松木）和长松（Pinus longaeva）（Great Basin刚毛松木）可以同时发生，并可能与相同种类的外生菌根真菌形成共生伙伴关系。这些共有的共生关系可以促进这些松树物种的持久性。P. flexilis和P. longaeva在他们的一生中也可能会组装独特的地下真菌群落，从而增加了古树的保护价值。我们使用了真菌rDNA的MiSeq测序来比较共生的P. flexilis和P. longaeva的真菌群落相似性根和土壤在美国犹他州犹他州森林动态图中的旧林中。我们用树木去核以测量树木的年龄，并确定真菌群落是否随着树木年龄的增长而变化。我们发现720个与柔韧性假单胞菌根相关的扩增子序列变体，736个与长假单胞菌根相关的变体和199个在两个松树之间共享的变体。尽管有相似的土壤群落，但柔韧性假单胞菌和长果假单胞菌的根系相关真菌群落明显不同。在P. flexilis根和P. longaeva土壤周围的真菌群落组成与年龄高达1340年的树龄有关。弯曲假单胞菌的根相关真菌群落P. longaeva的土壤群落随着树龄的增加而增加，这表明在老龄林中的年龄异质性促进了真菌的多样性。两种松树物种在根系相关真菌群落上的显着差异表明，它们可能与真菌群落参与了不同的双向选择。