Ectomycorrhizal fungi – fairy rings and the wood‐wide web

Many of us will have seen fairy rings, the mysterious circles of fungal fruiting bodies that occur in open grassy places or in forests. The secrecy about these rings is expressed in their naming: in English folklore, the rings were said to be caused by fairies dancing in a circle (Fig. 1) whereas in Germanspeaking Europe they are known as ‘Hexenringe’, stemming from an old mediaeval belief that they represented places where witches would have their gatherings. An old belief says that if you run around a fairy ring nine times on the first night of the new moon, you will hear sounds of music and laughter coming up from the underground home of the elves. Unlike this sorcerous practice, Lian et al . (this issue; pp. 825–836) used sturdy molecular techniques to provide insights into the below-ground fungal world of fairy rings formed by the ectomycorrhizal (ECM) basidiomycete Tricholoma matsutake . Using microsatellite markers they revealed the genetic composition of this species within and between fairy rings based on fruiting bodies as well as ECM tips, and they provide new information about the composition of other ECM species inside, beneath and outside of the rings using ITS polymorphism analysis. Another interesting aspect of this precise work is the use of microsatellite markers on ECM root tips to identify the genotypes of both the fungus matsutake and host Pinus densiflora , which allowed the authors to provide the first direct evidence that each fungal genotype colonized multiple pine trees and vice versa.