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From mycoheterotrophy to mutualism: mycorrhizal specificity and functioning in O phioglossum vulgatum sporophytes
Author(s) -
Field Katie J.,
Leake Jonathan R.,
Tille Stefanie,
Allinson Kate E.,
Rimington William R.,
Bidartondo Martin I.,
Beerling David J.,
Cameron Duncan D.
Publication year - 2015
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13263
Subject(s) - sporophyte , fern , biology , gametophyte , symbiosis , botany , mutualism (biology) , competition (biology) , ecology , bacteria , pollen , genetics
Summary Mycorrhizal functioning in the fern O phioglossum is complex and poorly understood. It is unknown whether mature O . vulgatum sporophytes form mutualistic associations with fungi of the G lomeromycota and with what specificity. Are green sporophytes able to ‘repay’ fungal carbon (C) invested in them by mycorrhizal partners during the initially heterotrophic gametophyte and early sporophyte stages of the lifecycle? We identified fungal partners of O . vulgatum sporophytes using molecular techniques and supplied them with 33 P‐orthophosphate and O . vulgatum sporophytes with 14 CO 2 . We traced the movement of fungal‐acquired nutrients and plant‐fixed C between symbionts and analysed natural abundance 13 C and 15 N isotope signatures to assess nutritional interactions. We found fungal specificity of O . vulgatum sporophytes towards a mycorrhizal fungus closely related to G lomus macrocarpum . Our radioisotope tracers revealed reciprocal C‐for‐phosphorus exchange between fern sporophytes and fungal partners, despite competition from surrounding vegetation. Monocultures of O . vulgatum were enriched in 13 C and 15 N, providing inconclusive evidence of mycoheterotrophy when experiencing competition from the surrounding plant community. We show mutualistic and specific symbiosis between a eusporangiate fern and fungi of the G lomeromycota. Our findings suggest a ‘take now, pay later’ strategy of mycorrhizal functioning through the lifecycle O . vulgatum , from mycoheterotrophic gametophyte to mutualistic aboveground sporophyte.