Mycorrhization helper bacteria: a case of specificity for altering ectomycorrhiza architecture but not ectomycorrhiza formation.
Mycorrhization helper bacteria (MHB), isolated from phylogenetically distinct ectomycorrhizal symbioses involving Lactarius rufus, Laccaria bicolor or Suillus luteus, were tested for fungus specificity to enhance L. rufus-Pinus sylvestris or L. bicolor-P. sylvestris mycorrhiza formation. As MHB isolated from the L. rufus and S. luteus mycorrhiza were originally characterised using a microcosm system, we assessed their ability to enhance mycorrhiza formation in a glasshouse system in order to determine the extent to which MHB are system-specific. Paenibacillus sp. EJP73, an MHB for L. rufus in the microcosm, significantly enhanced L. bicolor mycorrhiza formation in the glasshouse, demonstrating that the MHB effect of this bacterium is neither fungus-specific nor limited to the original experimental system. Although the five MHB strains studied were unable to significantly enhance L. rufus mycorrhiza formation, two of them did have a significant effect on dichotomous short root branching by L. rufus. The effect was specific to Paenibacillus sp. EJP73 and Burkholderia sp. EJP67, the two strains isolated from L. rufus mycorrhiza, and was not associated with auxin production. Altered mycorrhiza architecture rather than absolute number of mycorrhizal roots may be an important previously overlooked parameter for defining MHB effects.
Aspray
Thomas J
TJ
Warwick HRI, Wellesbourne, CV35 9EF, Warwickshire, UK. tom@ersremediation.com.
Frey-Klett
Pascale
P
UMR INRA/UHP 1136, Interactions Arbres/Micro-Organismes, Centre INRA de Nancy, 54280, Champenoux, France.
Jones
Julie E
JE
Warwick HRI, Wellesbourne, CV35 9EF, Warwickshire, UK.
Whipps
John M
JM
Warwick HRI, Wellesbourne, CV35 9EF, Warwickshire, UK.
Garbaye
Jean
J
UMR INRA/UHP 1136, Interactions Arbres/Micro-Organismes, Centre INRA de Nancy, 54280, Champenoux, France.
Bending
Gary D
GD
Warwick HRI, Wellesbourne, CV35 9EF, Warwickshire, UK.
D001419:Bacteria / Q000378:metabolism*; D001487:Basidiomycota / Q000166:cytology / Q000378:metabolism; D038821:Mycorrhizae / Q000166:cytology* / Q000378:metabolism*; D041605:Pinus sylvestris / Q000382:microbiology*; D018517:Plant Roots / Q000382:microbiology; D018520:Plant Shoots / Q000254:growth & development / Q000382:microbiology