Molecular aspects of the antagonistic interaction of smoke-derived butenolides on the germination process of Grand Rapids lettuce (Lactuca sativa) achenes

Authors

  • Vilmos Soós,

    1. Department of Applied Genomics, Agricultural Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Martonvásár, Hungary
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  • Endre Sebestyén,

    1. Department of Applied Genomics, Agricultural Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Martonvásár, Hungary
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  • Martin Posta,

    1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague 6, Czech Republic
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  • Ladislav Kohout,

    1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague 6, Czech Republic
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  • Marnie E. Light,

    1. Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
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  • Johannes Van Staden,

    1. Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
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  • Ervin Balázs

    Corresponding author
    1. Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
    • Department of Applied Genomics, Agricultural Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Martonvásár, Hungary
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Author for correspondence:

Ervin Balázs

Tel: +36 22 569 521

Email: balazs@mail.mgki.hu

Summary

  • Smoke-derived compounds provide a strong chemical signal to seeds in the soil seed bank, allowing them to take advantage of the germination niche created by the occurrence of fire. The germination stimulatory activity of smoke can largely be attributed to karrikinolide (KAR1), while a related compound, trimethylbutenolide (TMB), has been shown to have an inhibitory effect on germination. The aim of this study was to characterize the interaction of these potent fire-generated compounds.
  • Dose–response analysis, leaching tests and a detailed transcriptome study were performed using highly KAR1-sensitive lettuce (Lactuca sativa cv ‘Grand Rapids’) achenes.
  • Dose–response analysis demonstrated that the compounds are not competitors and TMB modulates germination in a concentration-dependent manner. The transcriptome analysis revealed a contrasting expression pattern induced by the compounds. KAR1 suppressed, while TMB up-regulated ABA, seed maturation and dormancy-related transcripts. The effect of TMB was reversed by leaching the compound, while the KAR1 effect was only reversible by leaching within the first 2 h of KAR1 treatment.
  • Our findings suggest that the compounds may act in concert for germination-related signaling. After the occurrence of fire, sufficient rainfall would contribute to post-germination seedling recruitment by reducing the concentration of the inhibitory compound.

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