Biology subjects

Hoysted, G. A.

Publications and source records attributed to Hoysted, G. A..

3 recordsLinked to original sources

bioRxiv2020

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

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.

plant biology↗

bioRxiv2020

Phenology and function in lycopod-Mucoromycotina symbiosis

Lycopodiella inundata is a lycophyte with a complex life cycle. The gametophytes and the juvenile, mature and retreating sporophytes form associations with Mucoromycotina fine root endophyte (MFRE) fungi, being mycoheterotrophic as gametophytes and mutualistic as mature sporophytes. However, the function of the symbiosis across juvenile and retreating sporophyte life stages remains unknown. We measured carbon-for-nutrient exchanges between L. inundata and MFRE across the transition from newly emerging sporophytes to mature sporophytes and in retreating adult sporophytes. We show MFRE fungi play distinct functional roles at each plant life stage, with evidence of bidirectional exchange of plant C for fungal acquired nutrients (N and P) between mature adult and retreating adult sporophytes and fungi, but no transfer of plant C to fungi and little fungal-acquired nutrient gain in juvenile sporophytes. Furthermore, we show that these functional stages correspond with different cytologies of colonisation. Our results show that MFRE have considerable plasticity in their interactions with the host plant which is related to the developmental stage of the host. This highlights the need for further research into symbiotic fungal function across plant life histories.

plant biology↗

bioRxiv2019

Mucoromycotina fine root endophyte fungi form nutritional mutualisms with vascular plants.

Fungi and plants have engaged in intimate symbioses that are globally widespread and have driven terrestrial biogeochemical processes since plant terrestrialisation >500 Mya. Recently, hitherto unknown nutritional mutualisms involving ancient lineages of fungi and non-vascular plants have been discovered. However, their extent and functional significance in vascular plants remains uncertain. Here, we provide first evidence of abundant carbon-for-nitrogen exchange between an early-diverging vascular plant (Lycopodiaceae) and Mucoromycotina (Endogonales) fine root endophyte regardless of changes in atmospheric CO2 concentration. Furthermore, we provide evidence that the same fungi also colonize neighbouring non-vascular and flowering plants. These findings fundamentally change our understanding of the evolution, physiology, interrelationships and ecology of underground plant-fungal symbioses in terrestrial ecosystems by revealing an unprecedented nutritional role of Mucoromycotina fungal symbionts in vascular plants.

plant biology↗