a Microbial Ecology Laboratory, Department of Mushroom Science and Forest Microbiology , Forestry and Forest Products Research Institute , 1 Matsunosato, Tsukuba , Ibaraki 305-8687 , Japan.
b Department of Plant Pathology , University of Florida , 2523 Fifield Hall, Gainesville , Florida 32611-0680.
Mycologia. 2018 May-Jun;110(3):473-481. doi: 10.1080/00275514.2018.1463130. Epub 2018 Jun 20.
Cenococcum geophilum forms sclerotia and ectomycorrhizas with host plants in forest soils. We demonstrated the differences in genetic diversity of C. geophilum between cultured isolates from sclerotia and those from ectomycorrhizal roots in the same 73 soil samples based on glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene sequences and newly developed microsatellite markers. Based on GAPDH sequences, 759 cultured isolates (553 from sclerotia and 206 from ectomycorrhizas) were classified into 107 "genotypes" with sequence variation of up to 8.6%. The total number of GAPDH genotypes per soil sample ranged from 1 to 9, but genotypes that were shared between sclerotia and ectomycorrhizas were uncommon (0-3 per soil sample). More than 50% of GAPDH genotypes were unique to one source in most soil samples. Unique GAPDH genotypes were detected from either scleotia or ectomycorrhizal roots in most of the soil samples. Multilocus analysis using nine microsatellite markers provided additional resolution to differentiate fungal individuals and supported the results of GAPDH genotyping. The results indicated that sampling both sclerotia and ectomycorrhizal roots maximizes the detection of diversity at the soil core scale. On the other hand, when all isolates were viewed together, 82 GAPDH genotypes were unique to sclerotia whereas only 6 GAPDH genotypes were unique to ectomycorrhizas. Rarefaction analysis indicated that GAPDH genotypic diversity is significantly higher in sclerotia than ectomycorrhizal roots and the diversity within sclerotia is nearly the same as that of both sclerotia and ectomycorrhizas together. These findings suggest that sampling sclerotia alone is likely to detect the majority of GAPDH genotypes in Cenococcum at the regional scale. When deciding whether to sample sclerotia, ectomycorrhizas, or both types of tissues from Cenococcum, it is critical to consider the spatial scale and also the main questions and hypotheses of the study.
胶膜革菌在森林土壤中形成菌核并与宿主植物形成外生菌根。我们基于甘油醛-3-磷酸脱氢酶（GAPDH）基因序列和新开发的微卫星标记，从同一 73 个土壤样本中的菌核和外生菌根培养分离物中，证明了胶膜革菌在遗传多样性方面的差异。基于 GAPDH 序列，759 株培养分离物（553 株来自菌核，206 株来自外生菌根）被分为 107 个“基因型”，序列变异高达 8.6%。每个土壤样本的 GAPDH 基因型总数范围为 1-9，但菌核和外生菌根之间共享的基因型并不常见（每个土壤样本 0-3 个）。在大多数土壤样本中，超过 50%的 GAPDH 基因型是某一个来源所特有的。在大多数土壤样本中，无论是菌核还是外生菌根，都能检测到独特的 GAPDH 基因型。使用 9 个微卫星标记的多点分析提供了区分真菌个体的额外分辨率，并支持 GAPDH 基因分型的结果。结果表明，同时采集菌核和外生菌根可以最大限度地提高核心尺度土壤多样性的检测。另一方面，当所有分离物一起观察时，82 个 GAPDH 基因型是菌核所特有的，而只有 6 个 GAPDH 基因型是外生菌根所特有的。稀有分析表明，GAPDH 基因型多样性在菌核中显著高于外生菌根，菌核内的多样性与菌核和外生菌根一起的多样性几乎相同。这些发现表明，单独采集菌核可能会在区域尺度上检测到胶膜革菌的大多数 GAPDH 基因型。在决定是否采集胶膜革菌的菌核、外生菌根或两者的组织时，必须考虑空间尺度以及研究的主要问题和假设。
