title: Growth inhibition of an Araucaria angustifolia (Coniferopsida) fungal seed pathogen, Neofusicoccum parvum, by soil streptomycetes.
abstract: BACKGROUND
  Araucariaceae are important forest trees of the southern hemisphere. Life expectancy of their seedlings can largely be reduced by fungal infections. In this study we have isolated and characterized such a fungus and investigated the potential of Streptomyces Actinobacteria from the respective rhizosphere to act as antagonists.
  
  
  RESULTS
  The pathogenic fungus from Araucaria angustifolia seeds was identified by morphological markers (pore-associated Woronin-bodies) as belonging to the Pezizomycotina. Molecular data identified the fungus as Neofusicoccum parvum (Botryosphaeriaceae). Co-cultures on agar of this fungus with certain streptomycete isolates from the rhizosphere, and from the surface of Araucaria roots significantly reduced the growth of the fungus. HPLC analysis of the agar yielded streptomycete-specific exudate compounds which were partly identified. There were differences in compounds between single (bacteria, fungus) and dual cultures (bacteria + fungus).
  
  
  CONCLUSIONS
  Streptomycetes from the rhizosphere of Araucariaceae produce exudates which can suppress the development of pathogenic fungi in their seeds.
authors.affiliation: Laboratory of Plant Biotechnology, Bioscience Institute, Pontifícia Universidade Católica do Rio Grande do Sul, Ipiranga Avenue 6681, Building 12A, CEP: 90619-900, Porto Alegre, RS, Brazil.
authors.forename: Fernando Rostirolla
authors.initials: FR
authors.lastname: Dalmas
authors.forename: Leandro
authors.initials: L
authors.lastname: Astarita
authors.forename: Luigi
authors.initials: L
authors.lastname: Defilippis
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Magel
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Fiedler
authors.forename: Robert
authors.initials: R
authors.lastname: Bauer
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Hampp
mesh_terms: D000935:Antifungal Agents / Q000032:analysis; D001203:Ascomycota / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification; D001688:Biological Products / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media / Q000737:chemistry; D056265:Microbial Interactions; D018517:Plant Roots / Q000382:microbiology; D012988:Soil Microbiology; D013302:Streptomyces / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism; D064028:Tracheophyta / Q000382:microbiology
chemical_list: D000935:Antifungal Agents; D001688:Biological Products; D003470:Culture Media