title: High functional diversity within species of arbuscular mycorrhizal fungi is associated with differences in phosphate and nitrogen uptake and fungal phosphate metabolism.
abstract: Plant growth responses following colonization with different isolates of a single species of an arbuscular mycorrhizal (AM) fungus can range from highly beneficial to detrimental, but the reasons for this high within-species diversity are currently unknown. To examine whether differences in growth and nutritional benefits are related to the phosphate (P) metabolism of the fungal symbiont, the effect of 31 different isolates from 10 AM fungal morphospecies on the P and nitrogen (N) nutrition of Medicago sativa and the P allocation among different P pools was examined. Based on differences in the mycorrhizal growth response, high, medium, and low performance isolates were distinguished. Plant growth benefit was positively correlated to the mycorrhizal effect on P and N nutrition. High performance isolates increased plant biomass by more than 170 % and contributed substantially to both P and N nutrition, whereas the effect of medium performance isolates particularly on the N nutrition of the host was significantly lower. Roots colonized by high performance isolates were characterized by relatively low tissue concentrations of inorganic P and short-chain polyphosphates and a high ratio between long- to short-chain polyphosphates. The high performance isolates belonged to different morphospecies and genera, indicating that the ability to contribute to P and N nutrition is widespread within the Glomeromycota and that differences in symbiotic performance and P metabolism are not specific for individual fungal morphospecies.
authors.affiliation: Biology and Microbiology Department, South Dakota State University, Brookings, SD, 57007, USA.
authors.forename: Jerry A
authors.initials: JA
authors.lastname: Mensah
authors.affiliation: Department of Biology, University of British Columbia Okanagan, Kelowna, British Columbia, V1V 1V7, Canada.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Koch
authors.affiliation: Department of Biology, Algoma University, Sault Ste. Marie, Ontario, P6A 2G4, Canada.
authors.forename: Pedro M
authors.initials: PM
authors.lastname: Antunes
authors.affiliation: Institute of Ecological Science, Vrije Universiteit, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands.
authors.forename: E Toby
authors.initials: ET
authors.lastname: Kiers
authors.affiliation: Department of Biology, University of British Columbia Okanagan, Kelowna, British Columbia, V1V 1V7, Canada.
authors.forename: Miranda
authors.initials: M
authors.lastname: Hart
authors.affiliation: Biology and Microbiology Department, South Dakota State University, Brookings, SD, 57007, USA. Heike.Bucking@sdstate.edu.
authors.forename: Heike
authors.initials: H
authors.lastname: Bücking
mesh_terms: D000455:Medicago sativa / Q000382:microbiology*; D038821:Mycorrhizae / Q000502:physiology*; D009584:Nitrogen / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D010710:Phosphates; D009584:Nitrogen
keywords: Arbuscular mycorrhizal symbiosis; Fungal diversity; Glomeromycota; Nitrogen; Nutrient uptake and transport; Phosphate