title: Functional analysis of liverworts in dual symbiosis with Glomeromycota and Mucoromycotina fungi under a simulated Palaeozoic CO2 decline.
abstract: Most land plants form mutualistic associations with arbuscular mycorrhizal fungi of the Glomeromycota, but recent studies have found that ancient plant lineages form mutualisms with Mucoromycotina fungi. Simultaneous associations with both fungal lineages have now been found in some plants, necessitating studies to understand the functional and evolutionary significance of these tripartite associations for the first time. We investigate the physiology and cytology of dual fungal symbioses in the early-diverging liverworts Allisonia and Neohodgsonia at modern and Palaeozoic-like elevated atmospheric CO2 concentrations under which they are thought to have evolved. We found enhanced carbon cost to liverworts with simultaneous Mucoromycotina and Glomeromycota associations, greater nutrient gain compared with those symbiotic with only one fungal group in previous experiments and contrasting responses to atmospheric CO2 among liverwort-fungal symbioses. In liverwort-Mucoromycotina symbioses, there is increased P-for-C and N-for-C exchange efficiency at 440 p.p.m. compared with 1500 p.p.m. CO2. In liverwort-Glomeromycota symbioses, P-for-C exchange is lower at ambient CO2 compared with elevated CO2. No characteristic cytologies of dual symbiosis were identified. We provide evidence of a distinct physiological niche for plant symbioses with Mucoromycotina fungi, giving novel insight into why dual symbioses with Mucoromycotina and Glomeromycota fungi persist to the present day.
authors.affiliation: School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
authors.forename: Katie J
authors.identifier: 0000-0002-5196-2360
authors.initials: KJ
authors.lastname: Field
authors.affiliation: Department of Life Sciences, Imperial College London, London, UK.|Jodrell Laboratory, Royal Botanic Gardens, Kew, UK.|Department of Life Sciences, Natural History Museum, London, UK.
authors.forename: William R
authors.initials: WR
authors.lastname: Rimington
authors.affiliation: Department of Life Sciences, Imperial College London, London, UK.|Jodrell Laboratory, Royal Botanic Gardens, Kew, UK.
authors.forename: Martin I
authors.initials: MI
authors.lastname: Bidartondo
authors.affiliation: Department of Animal and Plant Sciences, Western Bank, University of Sheffield, Sheffield, UK.
authors.forename: Kate E
authors.initials: KE
authors.lastname: Allinson
authors.affiliation: Department of Animal and Plant Sciences, Western Bank, University of Sheffield, Sheffield, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Beerling
authors.affiliation: Department of Animal and Plant Sciences, Western Bank, University of Sheffield, Sheffield, UK.
authors.forename: Duncan D
authors.initials: DD
authors.lastname: Cameron
authors.affiliation: Department of Life Sciences, Natural History Museum, London, UK.
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Duckett
authors.affiliation: Department of Animal and Plant Sciences, Western Bank, University of Sheffield, Sheffield, UK.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Leake
authors.affiliation: Department of Life Sciences, Natural History Museum, London, UK.
authors.forename: Silvia
authors.initials: S
authors.lastname: Pressel
mesh_terms: D005075:Biological Evolution; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000494:pharmacology*; D005658:Fungi / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D055137:Glomeromycota / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D035926:Hepatophyta / Q000187:drug effects / Q000382:microbiology* / Q000648:ultrastructure; D038821:Mycorrhizae / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology; D013559:Symbiosis
chemical_list: D002245:Carbon Dioxide; D002244:Carbon