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Extrafloral nectar secretion from wounds of Solanum dulcamara

Nature Plants volume 2, Article number: 16056 (2016) | Download Citation


Plants usually close wounds rapidly to prevent infections and the loss of valuable resources such as assimilates1. However, herbivore-inflicted wounds on the bittersweet nightshade Solanum dulcamara appear not to close completely and produce sugary wound secretions visible as droplets. Many plants across the plant kingdom secrete sugary nectar from extrafloral nectaries2 to attract natural enemies of herbivores for indirect defence3,4. As ants forage on wound edges of S. dulcamara in the field, we hypothesized that wound secretions are a form of extrafloral nectar (EFN). We show that, unlike EFN from known nectaries, wound secretions are neither associated with any specific structure nor restricted to certain locations. However, similar to EFN, they are jasmonate-inducible and the plant controls their chemical composition. Wound secretions are attractive for ants, and application of wound secretion mimics increases ant attraction and reduces herbivory on S. dulcamara plants in a natural population. In greenhouse experiments, we reveal that ants can defend S. dulcamara from two of its native herbivores, slugs and flea beetle larvae. Since nectar is defined by its ecological function as a sugary secretion involved in interactions with animals5, such ‘plant bleeding’ could be a primitive mode of nectar secretion exemplifying an evolutionary origin of structured extrafloral nectaries.

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  1. 1.

    & in Phloem: Molecular Cell Biology, Systemic Communication, Biotic Interactions (eds Thompson, G. A. & van Bel, A. J. E.) 141–153 (Wiley-Blackwell, 2012).

  2. 2.

    & in Secretions and Exudates in Biological Systems (eds Vivanco, J. M. & Baluška, F.) 187–219 (Springer, 2012).

  3. 3.

    Extrafloral nectar at the plant-insect interface: a spotlight on chemical ecology, phenotypic plasticity, and food webs. Annu. Rev. Entomol. 60, 213–232 (2015).

  4. 4.

    , & The diversity, ecology and evolution of extrafloral nectaries: current perspectives and future challenges. Ann. Bot. 111, 1243–1250 (2013).

  5. 5.

    , & (eds) Nectaries and Nectar (Springer, 2007).

  6. 6.

    in The Biology of Nectaries (eds Bentley, B. & Elias, T. S.) 174–203 (Columbia Univ. Press, 1983).

  7. 7.

    & The phylogenetic distribution of extrafloral nectaries in plants. Ann. Bot. 111, 1251–1261 (2013).

  8. 8.

    et al. A novel indirect defence in Brassicaceae: structure and function of extrafloral nectaries in Brassica juncea. Plant Cell Environ. 36, 528–541 (2013).

  9. 9.

    The floral and extra-floral nectaries of Passiflora. 2. The extra-floral nectary. Am. J. Bot. 69, 1420–1428 (1982).

  10. 10.

    World List of Plants with Extrafloral Nectaries (2014);

  11. 11.

    & Priming of indirect defences. Ecol. Lett. 9, 813–817 (2006).

  12. 12.

    , & Phloem sugar flux and jasmonic acid-responsive cell wall invertase control extrafloral nectar secretion in Ricinus communis. J. Chem. Ecol. 40, 760–769 (2014).

  13. 13.

    & Increased availability of extrafloral nectar reduces herbivory in Lima bean plants (Phaseolus lunatus, Fabaceae). Basic Appl. Ecol. 6, 237–248 (2005).

  14. 14.

    & Defensive plant-ants stabilize megaherbivore-driven landscape change in an African Savanna. Curr. Biol. 20, 1768–1772 (2010).

  15. 15.

    Analogous prey escape mechanisms in a pulmonate mollusk and lepidopterous larvae. J. New York Entomol. Soc. 80, 111–113 (1972).

  16. 16.

    , , & Observations of fire ants (Solenopsis invicta Buren) attacking apple snails (Pomacea paludosa Say) exposed during dry down conditions. J. Mollus Stud. 65, 507–510 (1999).

  17. 17.

    & Effects of insect attack to stems on plant survival, growth, reproduction and photosynthesis. Oikos 124, 266–273 (2015).

  18. 18.

    , & Sugar and amino acid composition of ant-attended nectar and honeydew sources from an Australian rainforest. Austral. Ecology 29, 418–429 (2004).

  19. 19.

    & Behavior of visitors at insect-produced analogs of extrafloral nectaries on Baccharis saroides Gray. Southwest Nat. 33, 275–286 (1988).

  20. 20.

    Ants protecting Banksia flowers from destructive insects? West Austral. Nat. 14, 151–154 (1979).

  21. 21.

    The occurrence and composition of manna in Eucalyptus and Angophora. Proc. Linn. Soc. New South Wales 90, 152–156 (1966).

  22. 22.

    A note on manna feeding by ants (Hymenoptera: Formicidae). J. Nat. Hist. 30, 1185–1192 (1996).

  23. 23.

    & Large-scale patterns of diversification in the widespread legume genus Senna and the evolutionary role of extrafloral nectaries. Evolution 64, 3570–3592 (2010).

  24. 24.

    & A selection mosaic in the facultative mutualism between ants and wild cotton. Proc. R. Soc. B 271, 2481–2488 (2004).

  25. 25.

    et al. Nectar secretion requires sucrose phosphate synthases and the sugar transporter SWEET9. Nature 508, 546–549 (2014).

  26. 26.

    Experimental-evidence for defense of Inga (Mimosoideae) saplings by ants. Ecology 65, 1787–1793 (1984).

  27. 27.

    & Enhancement of phloem exudation from cut petioles by chelating-agents. Plant Physiol. 53, 96–103 (1974).

  28. 28.

    et al. Metabolite profiling for plant functional genomics. Nature Biotechnol. 18, 1157–1161 (2000).

  29. 29.

    , , & TagFinder for the quantitative analysis of gas chromatography–mass spectrometry (GC–MS)-based metabolite profiling experiments. Bioinformatics 24, 732–737 (2008).

  30. 30.

    R: A language and environment for statistical computing v. 3.1.2 (R Foundation for Statistical Computing, 2014).

  31. 31.

    psych: Procedures for personality and psychological research v. 1.5.4 (Northwestern Univ., 2015).

  32. 32.

    lme4: Linear mixed-effects models using ‘Eigen’ and S4 v 1.1–7 (CRAN, 2014).

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We thank our students J. Schößler and M. Wank for help during experiments, A. Erban for assistance on the analysis of the GC–MS chromatograms, R. Radek for supporting SEM measurements and T. Sonsalla for help with figure art work. We thank the Freie Universität Berlin for funding as well as the German Research Foundation (DFG) for financial support to establish a German–Dutch cooperation (DFG: STE_2014_1_1). O.W.C. was funded by a grant of the bilateral agreement for higher education (Erasmus) between the Freie Universität Berlin and Radboud University, and a stipend of the CRC973 funded by the DFG. A.S. acknowledges funding by the CRC973 (project B2) and N.M.v.D. gratefully acknowledges the support of the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig funded by the German Research Foundation (FZT 118).

Author information


  1. Molecular Ecology, Dahlem Centre of Plant Sciences, Institute of Biology/Freie Universität Berlin, Haderslebener Strasse 9, 12163 Berlin, Germany

    • Tobias Lortzing
    • , Onno W. Calf
    • , Marlene Böhlke
    • , Daniel Geuß
    • , Susanne Kosanke
    •  & Anke Steppuhn
  2. Molecular Interaction Ecology, Institute of Water and Wetland Research, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands

    • Onno W. Calf
    •  & Nicole M. van Dam
  3. Applied Metabolome Analysis, Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany

    • Jens Schwachtje
    •  & Joachim Kopka
  4. German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany

    • Nicole M. van Dam
  5. Institute of Ecology, Friedrich Schiller University Jena, Dornburger-Strasse. 159, 07743 Jena, Germany

    • Nicole M. van Dam


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T.L. and A.S. designed this study. The experimental work was planned by T.L., A.S., O.W.C., N.M.v.D., and for metabolite analysis also by J.K. Experiments and analyses were conducted by T.L., O.W.C., M.B., D.G., S.K. and additionally by J.S. and J.K. for the metabolite analysis. T.L. and A.S. wrote the first draft of the manuscript that was edited and revised by all authors.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Anke Steppuhn.

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