Carbon for nutrient exchange between the lycophyte, Lycopodiella inundata and Mucoromycotina fine root endophytes is unresponsive to high atmospheric CO2 concentration

Abstract

Background and AimsNon-vascular plants associating with arbuscular mycorrhizal (AMF) and Mucoromycotina fine root endophyte (MFRE) fungi derive greater benefits from their fungal associates under higher atmospheric [CO2] than ambient, however nothing is known about how changes in [CO2] affects MFRE function in vascular plants. MethodsWe measured movement of phosphorus (P), nitrogen (N) and carbon (C) between the lycophyte, Lycopodiella inundata and Mucoromycotina fine root endophyte fungi using 33P-orthophosphate, 15N-ammonium chloride and 14CO2 isotope tracers under ambient and elevated atmospheric [CO2] concentrations of 440 and 800 ppm, respectively. Key ResultsTransfer of 33P and 15N from MFRE to plant were unaffected by changes in [CO2]. There was a slight increase in C transfer from plant to MFRE under elevated [CO2]. ConclusionsOur results demonstrate that the exchange of C-for-nutrients between a vascular plant and Mucoromycotina FRE is largely unaffected by changes in atmospheric [CO2]. Unravelling the role of MFRE in host plant nutrition and potential C-for-N trade changes between symbionts under varying abiotic conditions is imperative to further our understanding of the past, present and future roles of diverse plant-fungal symbioses in global ecosystems.