title: Plants as resource islands and storage units--adopting the mycocentric view of arbuscular mycorrhizal networks.
abstract: The majority of herbaceous plants are connected by arbuscular mycorrhizal (AM) fungi in complex networks, but how this affects carbon (C) and phosphorus (P) allocation among symbionts is poorly understood. We utilized a monoxenic AM system where hyphae from donor roots colonized two younger receiver roots of varying C status. AM fungal C allocation from donor to receiver compartments was followed by measuring the (13)C contents in fungal- and plant-specific lipids, and P movement from a hyphal compartment was traced using (33)P. Four times more (13)C was translocated from donor to C-limited receiver roots, but C remained in fungal tissue. Root C status did not influence the overall AM colonization, but arbuscule density was twice as high in non-C-limited roots, and they received 10 times more (33)P. The number of hyphal connections between compartments did not influence C and P allocation. Interestingly, there were more fungal storage lipids, but fewer structural lipids inside C-limited roots. Our results indicate that AM colonization may poorly reflect host quality as C can be supplied from neighboring roots. A mycocentric view of the symbiosis is proposed where C-delivering hosts are resource islands for the exchange of P for C, and C-limited hosts are storage units.
authors: Department of Biology, University of Copenhagen, Copenhagen, Denmark. ylva.lekberg@gmail.com
authors: Ylva
authors: Y
authors: Lekberg
authors: Edith Caroline
authors: EC
authors: Hammer
authors: Pål Axel
authors: PA
authors: Olsson
mesh_terms: D018533:Biomass; D002244:Carbon / Q000378:metabolism*; D002247:Carbon Isotopes / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis; D038821:Mycorrhizae / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*; D010761:Phosphorus Radioisotopes / Q000032:analysis; D018517:Plant Roots / Q000382:microbiology*; D012988:Soil Microbiology; D013559:Symbiosis
chemical_list: D002247:Carbon Isotopes; D005227:Fatty Acids; D010761:Phosphorus Radioisotopes; D010758:Phosphorus; D002244:Carbon