Modulation of plasma membrane H+-ATPase activity differentially activates wound and pathogen defense responses in tomato plants.
AUTOR(ES)
Schaller, A
RESUMO
Systemin is an important mediator of wound-induced defense gene activation in tomato plants, and it elicits a rapid alkalinization of the growth medium of cultured Lycopersicon peruvianum cells. A possible mechanistic link between proton fluxes across the plasma membrane and the induction of defense genes was investigated by modulating plasma membrane H+-ATPase activity. Inhibitors of H+-ATPase (erythrosin B, diethyl stilbestrol, and vanadate) were found to alkalinize the growth medium of L. peruvianum cell cultures and to induce wound response genes in whole tomato plants. Conversely, an activator of the H+-ATPase (fusicoccin) acidified the growth medium of L. peruvianum cell cultures and suppressed systemin-induced medium alkalinization. Likewise, in fusicoccin-treated tomato plants, the wound- and systemin-triggered accumulation of wound-responsive mRNAs was found to be suppressed. However, fusicoccin treatment of tomato plants led to the accumulation of salicylic acid and the expression of pathogenesis-related genes. Apparently, the wound and pathogen defense signaling pathways are differentially regulated by changes in the proton electrochemical gradient across the plasma membrane. In addition, alkalinization of the L. peruvianum cell culture medium was found to depend on the influx of Ca2+ and the activity of a protein kinase. Reversible protein phosphorylation was also shown to be involved in the induction of wound response genes. The plasma membrane H+-ATPase as a possible target of a Ca2+-activated protein kinase and its role in defense signaling are discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=144172Documentos Relacionados
- Sterol Modulation of the Plasma Membrane H+-ATPase Activity from Corn Roots Reconstituted into Soybean Lipids.
- H+-ATPase Activity from Storage Tissue of Beta vulgaris1: IV. N,N′-Dicyclohexylcarbodiimide Binding and Inhibition of the Plasma Membrane H+-ATPase
- Role of the Plasma Membrane H+-ATPase in K+ Transport.
- Energization of Transport Processes in Plants. Roles of the Plasma Membrane H+-ATPase1
- Fusicoccin Activates the Plasma Membrane H+-ATPase by a Mechanism Involving the C-Terminal Inhibitory Domain.
