Affiliation:
1. Dipartimento di Biologia Vegetale, Università di Roma “La Sapienza” Piazzale Aldo Moro 5, 00185 Roma, Italy (D.B., G.S., F.C., G.D.L.); and
2. Dipartimento di Biologia e Patologia Vegetale, Università degli Studi di Bari, via Orabona 4, 70100 Bari, Italy (N.D.)
Abstract
Abstract
α-1,4-Linked oligogalacturonides (OGs) inhibit auxin-regulated transcriptional activation of arolB-β-glucuronidase (GUS) gene fusion in tobacco (Nicotiana tabacum) leaf explants (D. Bellincampi, M. Cardarelli, D. Zaghi, G. Serino, G. Salvi, C. Gatz, F. Cervone, M.M. Altamura, P. Costantino, G. De Lorenzo [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 afterrolB promoter activation has initiated. OGs also induce a transient and catalase-sensitive accumulation of H2O2 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 H2O2accumulation. However, OG concentration for half-maximal induction of H2O2 accumulation is approximately 3-fold higher than that for half-maximal inhibition ofrolB promoter activity. The inhibition ofrolB promoter activity is not influenced by the addition of catalase or superoxide dismutase, suggesting that H2O2 and superoxide are not involved in this effect. A fungal oligo-β-glucan elicitor induces extracellular H2O2 accumulation at comparable or higher levels than those observed with OGs, but does not prevent the auxin-induced accumulation of GUS. We conclude that H2O2 produced upon treatment with OGs is not involved in the inhibition of the auxin-induced expression of therolB gene.
Publisher
Oxford University Press (OUP)
Subject
Plant Science,Genetics,Physiology
Cited by
252 articles.
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