title: Detection and quantification of a mycorrhization helper bacterium and a mycorrhizal fungus in plant-soil microcosms at different levels of complexity.
abstract: BACKGROUND
  Host plant roots, mycorrhizal mycelium and microbes are important and potentially interacting factors shaping the performance of mycorrhization helper bacteria (MHB). We investigated the impact of a soil microbial community on the interaction between the extraradical mycelium of the ectomycorrhizal fungus Piloderma croceum and the MHB Streptomyces sp. AcH 505 in both the presence and the absence of pedunculate oak microcuttings.
  
  
  RESULTS
  Specific primers were designed to target the internal transcribed spacer of the rDNA and an intergenic region between two protein encoding genes of P. croceum and the intergenic region between the gyrA and gyrB genes of AcH 505. These primers were used to perform real-time PCR with DNA extracted from soil samples. With a sensitivity of 10 genome copies and a linear range of 6 orders of magnitude, these real-time PCR assays enabled the quantification of purified DNA from P. croceum and AcH 505, respectively. In soil microcosms, the fungal PCR signal was not affected by AcH 505 in the absence of the host plant. However, the fungal signal became weaker in the presence of the plant. This decrease was only observed in microbial filtrate amended microcosms. In contrast, the PCR signal of AcH 505 increased in the presence of P. croceum. The increase was not significant in sterile microcosms that contained plant roots.
  
  
  CONCLUSIONS
  Real-time quantitative PCR assays provide a method for directly detecting and quantifying MHB and mycorrhizal fungi in plant microcosms. Our study indicates that the presence of microorganisms and plant roots can both affect the nature of MHB-fungus interactions, and that mycorrhizal fungi may enhance MHB growth.
authors.affiliation: Department Soil Ecology, UFZ - Helmholtz Centre for Environmental Research, Theodor-Lieser-Str, 4, 06120 Halle/Saale, Germany. florence.kurth@ufz.de.
authors.forename: Florence
authors.initials: F
authors.lastname: Kurth
authors.forename: Katharina
authors.initials: K
authors.lastname: Zeitler
authors.forename: Lasse
authors.initials: L
authors.lastname: Feldhahn
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Neu
authors.forename: Tilmann
authors.initials: T
authors.lastname: Weber
authors.forename: Václav
authors.initials: V
authors.lastname: Krištůfek
authors.forename: Tesfaye
authors.initials: T
authors.lastname: Wubet
authors.forename: Sylvie
authors.initials: S
authors.lastname: Herrmann
authors.forename: François
authors.initials: F
authors.lastname: Buscot
authors.forename: Mika T
authors.initials: MT
authors.lastname: Tarkka
mesh_terms: D058491:Bacterial Load; D001487:Basidiomycota / Q000254:growth & development / Q000502:physiology*; D015169:Colony Count, Microbial; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D056265:Microbial Interactions; D038821:Mycorrhizae / Q000254:growth & development / Q000502:physiology*; D018517:Plant Roots / Q000382:microbiology*; D060888:Real-Time Polymerase Chain Reaction; D012988:Soil Microbiology; D013302:Streptomyces / Q000254:growth & development / Q000502:physiology*
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial; D004271:DNA, Fungal
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