title: Interaction with ectomycorrhizal fungi and endophytic Methylobacterium affects nutrient uptake and growth of pine seedlings in vitro.
abstract: Tissues of Scots pine (Pinus sylvestris L.) contain several endophytic microorganisms of which Methylobacterium extorquens DSM13060 is a dominant species throughout the year. Similar to other endophytic bacteria, M. extorquens is able to colonize host plant tissues without causing any symptoms of disease. In addition to endophytic bacteria, plants associate simultaneously with a diverse set of microorganisms. Furthermore, plant-colonizing microorganisms interact with each other in a species- or strain-specific manner. Several studies on beneficial microorganisms interacting with plants have been carried out, but few deal with interactions between different symbiotic organisms and specifically, how these interactions affect the growth and development of the host plant. Our aim was to study how the pine endophyte M. extorquens DSM13060 affects pine seedlings and how the co-inoculation with ectomycorrhizal (ECM) fungi [Suillus variegatus (SV) or Pisolithus tinctorius (PT)] alters the response of Scots pine. We determined the growth, polyamine and nutrient contents of inoculated and non-inoculated Scots pine seedlings in vitro. Our results show that M. extorquens is able to improve the growth of seedlings at the same level as the ECM fungi SV and PT do. The effect of co-inoculation using different symbiotic organisms was seen in terms of changes in growth and nutrient uptake. Inoculation using M. extorquens together with ECM fungi improved the growth of the host plant even more than single ECM inoculation. Symbiotic organisms also had a strong effect on the potassium content of the seedling. The results indicate that interaction between endophyte and ECM fungus is species dependent, leading to increased or decreased nutrient content and growth of pine seedlings.
authors.affiliation: Department of Biology, University of Oulu, PO Box 3000, FIN-90014 Oulu, Finland johanna.pohjanen@oulu.fi.
authors.forename: Johanna
authors.initials: J
authors.lastname: Pohjanen
authors.affiliation: Department of Biology, University of Oulu, PO Box 3000, FIN-90014 Oulu, Finland.
authors.forename: Janne J
authors.initials: JJ
authors.lastname: Koskimäki
authors.affiliation: Department of Biology, University of Oulu, PO Box 3000, FIN-90014 Oulu, Finland.
authors.forename: Suvi
authors.initials: S
authors.lastname: Sutela
authors.affiliation: Department of Biology, University of Oulu, PO Box 3000, FIN-90014 Oulu, Finland.
authors.forename: Pavlo
authors.initials: P
authors.lastname: Ardanov
authors.affiliation: Department of Biology, University of Oulu, PO Box 3000, FIN-90014 Oulu, Finland.
authors.forename: Marja
authors.initials: M
authors.lastname: Suorsa
authors.affiliation: Finnish Forest Industries Federation, PO Box 336, FIN-00171 Helsinki, Finland.
authors.forename: Karoliina
authors.initials: K
authors.lastname: Niemi
authors.affiliation: Finnish Forest Research Institute, Parkano Research Unit, FIN-39700 Parkano, Finland.
authors.forename: Tytti
authors.initials: T
authors.lastname: Sarjala
authors.affiliation: Department of Biology, University of Oulu, PO Box 3000, FIN-90014 Oulu, Finland.
authors.forename: Hely
authors.initials: H
authors.lastname: Häggman
authors.affiliation: Department of Biology, University of Oulu, PO Box 3000, FIN-90014 Oulu, Finland.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Pirttilä
mesh_terms: D001487:Basidiomycota / Q000502:physiology*; D060026:Endophytes / Q000502:physiology; D020580:Methylobacterium / Q000502:physiology*; D038821:Mycorrhizae / Q000502:physiology; D041605:Pinus sylvestris / Q000254:growth & development* / Q000378:metabolism / Q000382:microbiology*; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology; D011073:Polyamines / Q000378:metabolism*; D036226:Seedlings / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology
chemical_list: D011073:Polyamines
keywords: Pinus sylvestris; Pisolithus tinctorius; Suillus variegatus; development; symbiosis