Plant and Cell Physiology Advance Access originally published online on October 8, 2005
Plant and Cell Physiology 2005 46(12):1964-1972; doi:10.1093/pcp/pci212
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Defense and Resistance-inducing Activities in Tobacco of the Sulfated ß-1,3 glucan PS3 and its Synergistic Activities with the Unsulfated Molecule
1 Institut de Biologie Moléculaire des Plantes du CNRS, Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg, France
2 Laboratoires Goëmar, Avenue du Général Patton, 35400 Saint Malo, France
* Corresponding author: Email, serge.kauffmann{at}ibmp-ulp.u-strasbg.fr; Fax, +33-388614442.
Laminarin, a ß-1,3 glucan with single ß-glucose branches at position 6, was chemically sulfated to produce PS3 with a degree of sulfation of 2.4. PS3 has previously been shown to activate the salicylic acid (SA) signaling pathway in infiltrated tobacco and Arabidopsis thaliana leaf tissues. Here, we investigated whether PS3 induces systemic defense and resistance responses in tobacco. Using a radiolabeled compound, it was first demonstrated that PS3 remains strictly localized to the infiltrated tissues. PS3 is also resistant to ß-glucanase degradation. In transgenic PR1ß-glucuronidase (GUS) tobacco plants, PS3 causes a strong increase in GUS activity in treated tissues but none in untreated leaves. PS3-infiltrated tissues challenged with tobacco mosaic virus (TMV) 8 d after elicitor application show a decrease in both the lesion number and the lesion size, whereas treatment with laminarin, the unsulfated native glucan, affected only the lesion number. PS3 does not induce systemic acquired resistance to TMV. PS3 and laminarin show synergistic effects in promoting the oxidative burst in tobacco cell suspensions and in increasing the expression of genes encoding O-methyltransferases of the phenylpropanoid pathway in tobacco plants. No synergistic effect was observed on the expression of either the SA-dependent acidic PR1 gene or the ethylene-dependent basic PR5 gene in tobacco plants.
3 Present address: INRA Colmar, UMR Vigne et Vins Alsace, Biologie du Développement de la Vigne, 28 rue de Herrlisheim, BP 507, 68021 Colmar cedex, France.
(Received June 27, 2005; Accepted October 1, 2005)
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