Growth inhibition of an Araucaria angustifolia (Coniferopsida) fungal seed pathogen, Neofusicoccum parvum, by soil streptomycetes
1 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
2 Centre for Environmental Sustainability, Faculty of Science, University of Technology Sydney, P.O. Box 123, Broadway/Sydney, NSW 2007, Australia
3 Wood Biology, Department of Wood Science, University of Hamburg, Leuschnerstrasse 91d, D-21031, Hamburg, Germany
4 Microbiology/Biotechnology, University of Tübingen, Auf der Morgenstelle 28, D-72076, Tuebingen, Germany
5 Plant Systematics, University of Tübingen, Auf der Morgenstelle 1, D-72076, Tuebingen, Germany
6 Physiological Ecology of Plants, University of Tübingen, Auf der Morgenstelle 1, D-72076, Tuebingen, Germany
BMC Microbiology 2013, 13:168 doi:10.1186/1471-2180-13-168Published: 18 July 2013
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.
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).
Streptomycetes from the rhizosphere of Araucariaceae produce exudates which can suppress the development of pathogenic fungi in their seeds.