Nod Factor and Elicitors Activate Different Phospholipid Signaling Pathways in Suspension-Cultured Alfalfa Cells1
AUTOR(ES)
den Hartog, Martine
FONTE
American Society of Plant Biologists
RESUMO
Lipo-chitooligosaccharides (Nod factors) are produced by symbiotic Rhizobium sp. bacteria to elicit Nod responses on their legume hosts. One of the earliest responses is the formation of phosphatidic acid (PA), a novel second messenger in plant cells. Remarkably, pathogens have also been reported to trigger the formation of PA in nonlegume plants. To investigate how host plants can distinguish between symbionts and pathogens, the effects of Nod factor and elicitors (chitotetraose and xylanase) on the formation of PA were investigated in suspension-cultured alfalfa (Medicago sativa) cells. Theoretically, PA can be synthesized via two signaling pathways, i.e. via phospholipase D (PLD) and via phospholipase C in combination with diacylglycerol (DAG) kinase. Therefore, a strategy involving differential radiolabeling with [32P]orthophosphate was used to determine the contribution of each pathway to PA formation. In support, PLD activity was specifically measured by using the ability of the enzyme to transfer the phosphatidyl group of its substrate to a primary alcohol. In practice, Nod factor, chitotetraose, and xylanase induced the formation of PA and its phosphorylated product DAG pyrophosphate within 2 min of treatment. However, whereas phospholipase C and DAG kinase were activated during treatment with all three different compounds, PLD was only activated by Nod factor. No evidence was obtained for the activation of phospholipase A2.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=166976Documentos Relacionados
- Prenylcysteine α-Carboxyl Methyltransferase in Suspension-Cultured Tobacco Cells1
- Convergence of Signaling Pathways Induced by Systemin, Oligosaccharide Elicitors, and Ultraviolet-B Radiation at the Level of Mitogen-Activated Protein Kinases in Lycopersicon peruvianum Suspension-Cultured Cells1
- Mitochondrial Contribution to the Anoxic Ca2+ Signal in Maize Suspension-Cultured Cells1
- Auxin Deprivation Induces Synchronous Golgi Differentiation in Suspension-Cultured Tobacco BY-2 Cells1
- Identification and Characterization of an 18-Kilodalton, VAMP-Like Protein in Suspension-Cultured Carrot Cells1