Identification of a Soluble, High-Affinity Salicylic Acid-Binding Protein in Tobacco.
AUTOR(ES)
Du, H.
RESUMO
Salicylic acid (SA) is a key component in the signal transduction pathway(s), leading to the activation of certain defense responses in plants after pathogen attack. Previous studies have identified several proteins, including catalase and ascorbate peroxidase, through which the SA signal might act. Here we describe a new SA-binding protein. This soluble protein is present in low abundance in tobacco (Nicotiana tabacum) leaves and has an apparent molecular weight of approximately 25,000. It reversibly binds SA with an apparent dissociation constant of 90 nM, an affinity that is 150-fold higher than that between SA and catalase. The ability of most analogs of SA to compete with labeled SA for binding to this protein correlated with their ability to induce defense gene expression and enhanced resistance. Strikingly, benzothiadiazole, a recently described chemical activator that induces plant defenses and disease resistance at very low rates of application, was the strongest competitor, being much more effective than unlabeled SA. The possible role of this SA-binding protein in defense signal transduction is discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=158255Documentos Relacionados
- Purification and characterization of a soluble salicylic acid-binding protein from tobacco.
- High-affinity salicylic acid-binding protein 2 is required for plant innate immunity and has salicylic acid-stimulated lipase activity
- Identification of a soluble salicylic acid-binding protein that may function in signal transduction in the plant disease-resistance response.
- A soluble, high-affinity, interleukin-4-binding protein is present in the biological fluids of mice.
- N-Acylethanolamine Signaling in Tobacco Is Mediated by a Membrane-Associated, High-Affinity Binding Protein1