Mycoheterotrophic germination of Pyrola asarifolia dust seeds reveals convergences with germination in orchids
Article first published online: 29 MAY 2012
© 2012 The Authors. New Phytologist © 2012 New Phytologist Trust
Volume 195, Issue 3, pages 620–630, August 2012
How to Cite
Hashimoto, Y., Fukukawa, S., Kunishi, A., Suga, H., Richard, F., Sauve, M. and Selosse, M.-A. (2012), Mycoheterotrophic germination of Pyrola asarifolia dust seeds reveals convergences with germination in orchids. New Phytologist, 195: 620–630. doi: 10.1111/j.1469-8137.2012.04174.x
- Issue published online: 9 JUL 2012
- Article first published online: 29 MAY 2012
- Received: 25 February 2012, Accepted: 6 April 2012
- dust seeds;
- host specificity;
- mycorrhizal networks;
- •Dust seeds that germinate by obtaining nutrients from symbiotic fungi have evolved independently in orchids and 11 other plant lineages. The fungi involved in this ‘mycoheterotrophic’ germination have been identified in some orchids and non-photosynthetic Ericaceae, and proved identical to mycorrhizal fungi of adult plants. We investigated a third lineage, the Pyroleae, chlorophyllous Ericaceae species whose partial mycoheterotrophy at adulthood has recently attracted much attention.
- •We observed experimental Pyrola asarifolia germination at four Japanese sites and investigated the germination pattern and symbiotic fungi, which we compared to mycorrhizal fungi of adult plants.
- •Adult P. asarifolia, like other Pyroleae, associated with diverse fungal species that were a subset of those mycorrhizal on surrounding trees. Conversely, seedlings specifically associated with a lineage of Sebacinales clade B (endophytic Basidiomycetes) revealed an intriguing evolutionary convergence with orchids, some of which also germinate with Sebacinales clade B. Congruently, seedlings clustered spatially together, but not with adults.
- •This unexpected transition in specificity and ecology of partners could support the developmental transition from full to partial mycoheterotrophy, but probably challenges survival and distribution during development. We discuss the physiological and ecological traits that predisposed to the repeated recruitment of Sebacinales clade B for dust seed germination.