Fungal elicitors induce a transient release of active oxygen species from cultured spruce cells that is dependent on Ca2+ and protein-kinase activity

Abstract

Cell-wall components from the ectomycorrhizal fungi Amanita muscaria and Hebeloma crustuliniforme and from the spruce pathogen Heterobasidion annosum elicited a transient release of active oxygen species from cultured spruce cells (Picea abies (L.) Karst.). Since the detection of active oxygen was suppressed by catalase, H2O2 was assumed to be the prevailing O2 species. On the other hand, superoxide dismutase enhanced the concentration of detectable H2O2 indicating that the superoxide anion was formed before dismutating to H2O2. The elicitors induced the formation of active oxygen in a dose-dependent manner. Interestingly, elicitors from mycorrhizal fungi had a lower H2O2-inducing activity than equal amounts of cell-wall preparations from the pathogen H. annosum. In Ca(2+)-depleted medium the production of active oxygen by elicitor-treated spruce cells was suppressed. Additionally, the ionophore A 23187 induced active oxygen formation in a medium with Ca(2+) but not in a Ca(2+)-depleted medium. Furthermore, the protein-kinase inhibitor staurosporine inhibited the oxidative burst. At a concentration of 34 nM the effect was diminished to 50%. From these results it is suggested that the release of active oxygen species from cultured spruce cells triggered by cell-wall-derived fungal elicitors depends on external Ca(2+) and a protein-kinase activity. In these respects the effect shows similarities with the well-studied respiratory burst of mammalian neutrophils.

Generation of active oxygen in elicited cells of Arabidopsis thaliana is mediated by a NADPH oxidase‐like enzyme

“…We found that washing and equilibration of cells were essential to reduce high levels of AOS in non-elicited cells. This has been observed with other species [14,16,22], possibly due to substances that interfere with CL. Moreover, mechanical agitation of cells may also induce AOS production [23,24].…”

Ethylene Signal Is Transduced via Protein Phosphorylation Events in Plants.

“…In plants, protein phosphorylation was shown to play a direct regulatory role in light response (for reviews, see Bennett, 1991;Alien, 1992) and circadian rhythms (Carter et al, 1991). Correlations between protein phosphorylation and physiological response were demonstrated in pollen embryogenesis (Kyo and Harada, 1990) and fungal elicitor treatment of cultured cells (Grab et al, 1989;Dietrich et al, 1990;Grosskopf et al, 1990;Felix et al, 1991;Schwacke and Hager, 1992). Here, with the use of specific kinase and phosphatase inhibitors, we show that phosphorylation events are essential for the ethylene-mediated pathogenesis response in tobacco plants.…”

Death Don't Have No Mercy: Cell Death Programs in Plant-Microbe Interactions.

“…A requirement for calcium influx for subsequent signaling events has been demonstrated in at least some systems (Schwacke and Hager, 1992;He et al, 1993;Nurnberger et al, 1994;Hahlbrock et al, 1995;Tavernier et al, 1995). Anion channel blockers prevent activation of the oxidative burst and defense gene transcription in parsley cells treated with fungal elicitor (T. Jabs and D. Scheel, personal communication).…”