Extracellular H2O2 Induced by Oligogalacturonides Is Not Involved in the Inhibition of the Auxin-Regulated rolB Gene Expression in Tobacco Leaf Explants (original) (raw)

1996] Plant Cell 8: 477-487). In this paper we show that inhibition by OGs is very rapid, with a short lag time, and takes place even after rolB promoter activation has initiated. OGs also induce a transient and catalase-sensitive accumulation of H 2 O 2 in the leaf explant culture medium. OGs with a degree of polymerization from 12 to 15 are required for both the inhibition of the auxin-induced rolB-driven accumulation of GUS and the induction of H 2 O 2 accumulation . However, OG concentration for half-maximal induction of H 2 O 2 accumulation is approximately 3-fold higher than that for halfmaximal inhibition of rolB promoter activity. The inhibition of rolB promoter activity is not influenced by the addition of catalase or superoxide dismutase, suggesting that H 2 O 2 and superoxide are not involved in this effect. A fungal oligo-␤-glucan elicitor induces extracellular H 2 O 2 accumulation at comparable or higher levels than those observed with OGs, but does not prevent the auxininduced accumulation of GUS. We conclude that H 2 O 2 produced upon treatment with OGs is not involved in the inhibition of the auxin-induced expression of the rolB gene. Eberhard S, Darvill A, Albersheim P (1993) Oligogalacturonides inhibit the formation of roots on tobacco explants. Plant J 4: 207-213 Bradford MM (1976) A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 72: 248-254 Branca C, De Lorenzo G, Cervone F (1988) Competitive inhibition of the auxin-induced elongation by ␣-d-oligogalacturonides in pea stem segments. Physiol Plant 72: 499-504 Brisson LF, Tenhaken R, Lamb C (1994) Function of oxidative cross-linking of cell wall structural proteins in plant disease resistance. Plant Cell 6: 1703-1712 Capone I, Cardarelli M, Mariotti D, Pomponi M, De Paolis A, Costantino P (1991) Different promoter regions control level and tissue specificity of expression of Agrobacterium rhizogenes rolB gene in plants. Plant Mol Biol 16: 427-436 Cervone F, Castoria R, Leckie F, De Lorenzo G (1997) Perception of fungal elicitors and signal transduction. In P Aducci, ed, Signal transduction in plants. Birkäuser Verlag, Basel, pp 153-177 Cheong J-J, Birberg W, Fü gedi P, Pilotti Å, Garegg PJ, Hong N, Ogawa T, Hahn MG (1991) Structure-activity relationships of oligo-␤-glucoside elicitors of phytoalexin accumulation in soybean. Plant Cell 3: 127-136 (1994) Polygalacturonase, PGIP and oligogalacturonides in cellcell communication. Biochem Soc Trans 22: 396-399 Eberhard S, Doubrava N, Marfà V, Mohnen D, Southwick A, Darvill A, Albersheim P (1989) Pectic cell wall fragments regulate tobacco thin-cell-layer explant morphogenesis. Plant Cell 1: 747-755 Fauth M, Merten A, Hahn MG, Jeblick W, Kauss H (1996) Competence for elicitation of H 2 O 2 in hypocotyls of cucumber is induced by breaching the cuticle and is enhanced by salicylic acid. Plant Physiol 110: 347-354 Felix G, Baureithel K, Boller T (1998) Desensitization of the perception system for chitin fragments in tomato cells. Plant Physiol 117: 643-650 Hahn MG, Darvill A, Albersheim P, Bergmann C, Cheong J-J, Koller A, Lò V-M (1991) Preparation and characterization of oligosaccharide elicitors of phytoalexin accumulation.