title: Metal-chelating compounds produced by ectomycorrhizal fungi collected from pine plantations.
abstract: OBJECTIVE
  To investigate the in vitro production of metal-chelating compounds by ectomycorrhizal fungi collected from pine plantations in southern Chile.
  
  
  RESULTS
  Scleroderma verrucosum, Suillus luteus and two isolates of Rhizopogon luteolus were grown in solid and liquid modified Melin-Norkans (MMN) media with and without iron addition and the production of iron-chelating compounds was determined by Chrome Azurol S (CAS) assay. The presence of hydroxamate and catecholate-type compounds and organic acids was also investigated in liquid medium. All isolates produced iron-chelating compounds as detected by CAS assay, and catecholates, hydroxamates as well as oxalic, citric and succinic acids were also detected in all fungal cultures. Scleroderma verrucosum produced the greatest amounts of catecholates and hydroxamates whereas the highest amounts of organic acids were detected in S. luteus. Nevertheless, the highest catecholate, hydroxamate and organic acid concentrations did not correlate with the highest CAS reaction which was observed in R. luteolus (Yum isolate).
  
  
  CONCLUSIONS
  Ectomycorrhizal fungi produced a variety of metal-chelating compounds when grown in liquid MMN medium. However, the addition of iron to all fungi cultures reduced the CAS reaction, hydroxamate and organic acid concentrations. Catecholate production was affected differently by iron, depending on the fungal isolate.
  
  
  CONCLUSIONS
  The ectomycorrhizal fungi described in this study have never been reported to produce metal-chelating compound production. Moreover, apart from some wood-rotting fungi, this is the first evidence of the presence of catecholates in R. luteolus, S. luteus and S. verrucosum cultures.
authors.affiliation: Departamento Forestal, Universidad de Concepción, Campus Los Angeles, Los Angeles, Chile. angmachu@udec.cl
authors.forename: A
authors.initials: A
authors.lastname: Machuca
authors.forename: G
authors.initials: G
authors.lastname: Pereira
authors.forename: A
authors.initials: A
authors.lastname: Aguiar
authors.forename: A M F
authors.initials: AM
authors.lastname: Milagres
mesh_terms: D001487:Basidiomycota / Q000378:metabolism*; D002614:Chelating Agents / Q000302:isolation & purification / Q000494:pharmacology; D003470:Culture Media / Q000737:chemistry*; D006877:Hydroxamic Acids / Q000302:isolation & purification; D007501:Iron / Q000378:metabolism; D008828:Microbiological Techniques; D041605:Pinus sylvestris / Q000382:microbiology*; D017262:Siderophores / Q000096:biosynthesis* / Q000302:isolation & purification
chemical_list: D002614:Chelating Agents; D003470:Culture Media; D006877:Hydroxamic Acids; D017262:Siderophores; D007501:Iron