Microbial Ecology

, Volume 63, Issue 2, pp 418–428 | Cite as

Microbial Diversity Inside Pumpkins: Microhabitat-Specific Communities Display a High Antagonistic Potential Against Phytopathogens

  • Michael Fürnkranz
  • Birgit Lukesch
  • Henry Müller
  • Herbert Huss
  • Martin Grube
  • Gabriele BergEmail author
Plant Microbe Interactions


Recent and substantial yield losses of Styrian oil pumpkin (Cucurbita pepo L. subsp. pepo var. styriaca Greb.) are primarily caused by the ascomycetous fungus Didymella bryoniae but bacterial pathogens are frequently involved as well. The diversity of endophytic microbial communities from seeds (spermosphere), roots (endorhiza), flowers (anthosphere), and fruits (carposphere) of three different pumpkin cultivars was studied to develop a biocontrol strategy. A multiphasic approach combining molecular, microscopic, and cultivation techniques was applied to select a consortium of endophytes for biocontrol. Specific community structures for Pseudomonas and Bacillus, two important plant-associated genera, were found for each microenvironment by fingerprinting of 16S ribosomal RNA genes. All microenvironments were dominated by bacteria; fungi were less abundant. Of the 2,320 microbial isolates analyzed in dual culture assays, 165 (7%) were tested positively for in vitro antagonism against D. bryoniae. Out of these, 43 isolates inhibited the growth of bacterial pumpkin pathogens (Pectobacterium carotovorum, Pseudomonas viridiflava, Xanthomonas cucurbitae); here only bacteria were selected. Microenvironment-specific antagonists were found, and the spermosphere and anthosphere were revealed as underexplored reservoirs for antagonists. In the latter, a potential role of pollen grains as bacterial vectors between flowers was recognized. Six broad spectrum antagonists selected according to their activity, genotypic diversity, and occurrence were evaluated under greenhouse conditions. Disease severity on pumpkins of D. bryoniae was significantly reduced by Pseudomonas chlororaphis treatment and by a combined treatment of strains (Lysobacter gummosus, P. chlororaphis, Paenibacillus polymyxa, and Serratia plymuthica). This result provides a promising prospect to biologically control pumpkin diseases.


Pumpkin Seed Paenibacillus Polymyxa Mycelium Fragment Ascomycetous Fungus Pectobacterium Carotovorum 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



We thank Massimiliano Cardinale, Martina Köberl, and Christin Zachow (Graz) for valuable support. Furthermore, we want to thank Johanna Winkler (Saatzucht Gleisdorf) for excellent cooperation regarding pumpkin cultivars and field trials. The project was funded by the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management and the governments of the Federal State of Styria.

Supplementary material

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Figure S1 (DOC 1.03 MB)
248_2011_9942_MOESM2_ESM.doc (212 kb)
Figure S2 (DOC 212 kb)


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Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Michael Fürnkranz
    • 1
  • Birgit Lukesch
    • 1
  • Henry Müller
    • 1
  • Herbert Huss
    • 2
  • Martin Grube
    • 3
  • Gabriele Berg
    • 1
    Email author
  1. 1.Institute of Environmental BiotechnologyGraz University of TechnologyGrazAustria
  2. 2.Agricultural Research & Education Centre Raumberg-GumpensteinField Trial Station Lambach/Stadl-PauraStadl-PauraAustria
  3. 3.Institute of Plant SciencesKarl-Franzens-University GrazGrazAustria

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