Multi‐host ectomycorrhizal fungi are predominant in a Guinean tropical rainforest and shared between canopy trees and seedlings

6 Embrapa Agrobiologia km 47, antiga estrada Rio-Sao Paulo, Seropedica 23851-970 Brazil. Summary The diversity of ectomycorrhizal (ECM) fungi on adult trees and seedlings of five species, Anthonotha fra- grans, Anthonotha macrophylla, Cryptosepalum tet- raphyllum, Paramacrolobium coeruleum and Uapaca esculenta, was determined in a tropical rain forest of Guinea. Ectomycorrhizae were sampled within a surface area of 1600 m 2 , and fungal taxa were identi- fied by sequencing the rDNA Internal Transcribed Spacer region. Thirty-nine ECM fungal taxa were determined, of which 19 multi-hosts, 9 single-hosts and 11 singletons. The multi-host fungi represented 92% (89% when including the singletons in the analy- sis) of the total abundance. Except for A. fragrans, the adults of the host species displayed significant differ- entiation for their fungal communities, but their seed- lings harboured a similar fungal community. These findings suggest that there was a potential for the formation of common mycorrhizal networks in close vicinity. However, no significant difference was detected for the d 13 C and d 15 N values between seed- lings and adults of each ECM plant, and no ECM species exhibited signatures of mixotrophy. Our results revealed (i) variation in ECM fungal diversity according to the seedling versus adult development stage of trees and (ii) low host specificity of ECM fungi, and indicated that multi-host fungi are more abundant than single-host fungi in this forest stand.