Abstract
Non-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] (a[CO2]) than ambient; however, nothing is known about how changes in a[CO2] affect MFRE function in vascular plants. We measured movement of phosphorus (P), nitrogen (N) and carbon (C) between the lycophyte Lycopodiella inundata and Mucoromycotina fine root endophyte fungi using 33P-orthophosphate, 15 N-ammonium chloride and 14CO2 isotope tracers under ambient and elevated a[CO2] concentrations of 440 and 800 ppm, respectively. Transfers of 33P and 15 N from MFRE to plants were unaffected by changes in a[CO2]. There was a slight increase in C transfer from plants to MFRE under elevated a[CO2]. Our results demonstrate that the exchange of C-for-nutrients between a vascular plant and Mucoromycotina FRE is largely unaffected by changes in a[CO2]. Unravelling the role of MFRE in host plant nutrition and potential C-for-N trade changes between symbionts under different abiotic conditions is imperative to further our understanding of the past, present and future roles of plant-fungal symbioses in ecosystems.
Highlights
Changes in atmospheric CO2 concentration (a[CO2]) have been a prominent feature throughout Earth’s environmental history (Leaky and Lau 2012)
Analysis of experimental Lycopodiella inundata plants grown under ambient and elevated a[CO2] confirmed that they were colonised by Mucoromycotina fine root endophyte fungi within Endogonales
Our results demonstrate for the first time that the exchange of C-for-nutrients between a vascular plant and Mucoromycotina ‘fine root endophyte’ (MFRE) symbionts is largely unaffected by changes in a [CO2], with MFRE maintaining 33P and 15 N assimilation and transfer to the plant host across a [CO2] treatments (Fig. 3a, b), despite MFRE colonisation being more abundant within the roots of plants grown under elevated a [CO2]
Summary
Changes in atmospheric CO2 concentration (a[CO2]) have been a prominent feature throughout Earth’s environmental history (Leaky and Lau 2012). Around 500 Mya, plants made the transition from an aquatic to a terrestrial existence (Morris et al 2018), facilitated by symbiotic fungi (Nicolson 1967; Pirozynski and Malloch 1975). These ancient fungal symbionts are thought to have played an important role in helping early land plants access scarce nutrients from the substrate onto which they had emerged, in much the same way as modern-day mycorrhizal fungi form nutritional mutualisms with plants (Pirozynski and Malloch 1975; Krings et al 2012; Strullu-Derrien et al 2014). It is highly likely that ancient mycorrhiza-like (or paramycorrhiza sensu Strullu-Derrien and Strullu 2007) fungi were closely related to, and subsequently evolved into, modern arbuscular mycorrhizal fungi (AMF) belonging to
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
