The algal polysaccharide carrageenans can act as an elicitor of plant defence

Authors

  • Laurence Mercier,

    1. UMR CNRS-UPS 5546 ‘Signaux et Messages Cellulaires chez les Végétaux’, Pôle de Biotechnologie Végétale, 24, chemin de Borde-Rouge, BP17 Auzeville, F-31326 Castanet-Tolosan, France;
    2. SECMA Biotechnologies Marines, BP 65, F-22260 Pontrieux, France
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  • Claude Lafitte,

    1. UMR CNRS-UPS 5546 ‘Signaux et Messages Cellulaires chez les Végétaux’, Pôle de Biotechnologie Végétale, 24, chemin de Borde-Rouge, BP17 Auzeville, F-31326 Castanet-Tolosan, France;
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  • Gisèle Borderies,

    1. UMR CNRS-UPS 5546 ‘Signaux et Messages Cellulaires chez les Végétaux’, Pôle de Biotechnologie Végétale, 24, chemin de Borde-Rouge, BP17 Auzeville, F-31326 Castanet-Tolosan, France;
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  • Xavier Briand,

    1. SECMA Biotechnologies Marines, BP 65, F-22260 Pontrieux, France
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  • Marie-Thérèse Esquerré-Tugayé,

    1. UMR CNRS-UPS 5546 ‘Signaux et Messages Cellulaires chez les Végétaux’, Pôle de Biotechnologie Végétale, 24, chemin de Borde-Rouge, BP17 Auzeville, F-31326 Castanet-Tolosan, France;
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  • Joëlle Fournier

    1. UMR CNRS-UPS 5546 ‘Signaux et Messages Cellulaires chez les Végétaux’, Pôle de Biotechnologie Végétale, 24, chemin de Borde-Rouge, BP17 Auzeville, F-31326 Castanet-Tolosan, France;
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Author for correspondence: Joëlle Fournier Tel: +33 5 62 19 35 14 Fax: +33 5 62 19 35 25 Email:fournier@smcv.ups-tlse.fr

Abstract

  • • Effects of two algal polysaccharides, laminarin and carrageenans, on defence responses and signalling in tobacco plants is presented. A possible role as defence elicitors is important in the context of the use of algal extracts as plant protectants.
  • • The effect of the extracts was assessed after infiltration of tobacco leaves, and compared to the effect of a known elicitor of Phytophthora parasitica var. nicotianae(Ppn).
  • • Of the two algal polysaccharides, only carrageenans efficiently induced signalling and defence gene expression in tobacco leaves, as observed with Ppn elicitor. λ-carrageenan, with its high sulphate content, proved the most active. Defence genes encoding sesquiterpene cylase, chitinase and proteinase inhibitor were induced locally, and the signalling pathways mediated by ethylene, jasmonic acid and salicylic acid, were triggered. Some effects lasted for at least a week.
  • • λ-Carrageenan can elicit an array of plant defence responses, possibly through an effect of its high sulphate content. This helps clarify the mechanism of plant protection by algal extracts.

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