Mycological Research



Molecular and anatomical evidence for a three-way association between Pinus sylvestris and the ectomycorrhizal fungi Suillus bovinus and Gomphidius roseus


Pål Axel OLSSON a1, Babette MÜNZENBERGER a2, Shahid MAHMOOD a1 and Susanne ERLAND a1
a1 Department of Microbial Ecology, Ecology Building, Lund University, SE-223 62 Lund, Sweden
a2 Institute of Primary Production and Microbial Ecology, Dr.-Zinn-Weg 18, D-16225 Eberswalde, Germany. E-mail: pal_axel.olsson@mbioekol.lu.se

Abstract

Many intimate associations between different species of ectomycorrhizal fungi are inferred on the basis of the consistent co-occurrence of their fruit bodies. Suillus bovinus and Gomphidius roseus, where the latter never occurs without the former, is one example. This association was examined with PCR identification and light microscopy. S. bovinus and G. roseus were unambiguously separated on the basis of RFLPs of the PCR-amplified ITS region of ribosomal DNA. Tuberculate mycorrhizas of Pinus sylvestris sampled under fruit bodies of G. roseus and S. bovinus were investigated and the majority were identified as mixed associations involving both G. roseus and S. bovinus. Tuberculate mycorrhizas, which macroscopically resemble the ones of Suillus species, contained typical chlamydospores of G. roseus and they had haustoria where G. roseus hyphae penetrated the cortical root cells. Pine seedlings collected near the fruit bodies of the two species were mainly colonised by S. bovinus. Mycelial rhizomorphs collected under the fruit bodies of G. roseus were identified as S. bovinus, while both fungal species were present at the base of G. roseus fruit bodies. The significance of these observations and the possibility that G. roseus acts as a parasite are discussed.

(Received October 28 1999)
(Accepted February 14 2000)