Mycorrhizal associations in recently diverged Epipactis species

In orchid species that have populations occurring in strongly contrasting habitats, mycorrhizal divergence and other habitat-specific adaptations may lead to the formation of reproductively isolated taxa and ultimately to species formation. In this study, Jacquemyn et al. used 454 amplicon pyrosequencing to investigate mycorrhizal communities associating with Epipactis helleborine in its typical forest habitat and with its presumed sister species E. neerlandica that almost exclusively occurs in coastal dune habitats.

Putative mycorrhizal fungi detected in three species of the genus Epipactis.
Putative mycorrhizal fungi detected in three species of the genus Epipactis. (A) The number of operational taxonomic units (OTUs; defined at a 3 % ITS sequence dissimilarity level) for different fungal genera. (B) Frequency distribution of sequence numbers for the 15 most abundant fungal genera. Image: Jacquemyn et al.

E. helleborine and E. neerlandica associated with strongly divergent mycorrhizal communities, so detailed experiments on habitat-specific adaptations in general and mycorrhizal divergence to the process of speciation in orchids are required.

Reference List

Hans Jacquemyn, Michael Waud, Bart Lievens, Rein Brys, 2016, 'Differences in mycorrhizal communities betweenEpipactis palustris,E. helleborineand its presumed sister speciesE. neerlandica', Annals of Botany, vol. 118, no. 1, pp. 105-114 http://dx.doi.org/10.1093/aob/mcw015