Oligogalacturonides and chitosan activate plant defensive genes through the octadecanoid pathway

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 92; no. 10; pp. 4095 - 4098
• Main Authors: Doares, S.H. (Washington State University, Pullman, WA.), Syrovets, T, Weiler, E.W, Ryan, C.A
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 09-05-1995; National Acad Sciences; National Academy of Sciences
• Subjects: ANTIMETABOLITE; ANTIMETABOLITOS; ARN MENSAJERO; ARN MESSAGER; Biochemistry; Botany; CHITINE; EXPRESION GENICA; EXPRESSION DES GENES; Fatty acids; FEUILLE; Flowers & plants; Genes; HOJAS; INHIBIDORES DE ENZIMAS; INHIBIDORES DEL CRECIMIENTO; INHIBITEUR D'ENZYME; Leaves; LYCOPERSICON ESCULENTUM; OLIGOSACARIDOS; OLIGOSACCHARIDE; Oligosaccharides; Pathogens; PEPTIDE; PEPTIDOS; Plant cells; Plants; POLIURONIDOS; POLYURONIDE; PROTEASAS; PROTEASE; Protease inhibitors; QUITINA; RETARDATEUR DE CROISSANCE; SINTESIS DE PROTEINAS; Sodium; Stems; SYNTHESE PROTEIQUE
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.92.10.4095

Jasmonic acid, synthesized from linolenic acid (the octadecanoid pathway), has been proposed to be part of a signal transduction pathway that mediates the induction of defensive genes in plants in response to oligouronide and polypeptide signals generated by insect and pathogen attacks. We report here that the induction of proteinase inhibitor accumulation in tomato leaves by plant-derived oligogalacturonides and fungal-derived chitosan oligosaccharides is severely reduced by two inhibitors (salicylic acid and diethyldi-thiocarbamic acid) of the octadecanoid pathway, supporting a role for the pathway in signaling by oligosaccharides. Jasmonic acid levels in leaves of tomato plants increased several fold within 2 hr after supplying the polypeptide systemin, oligogalacturonides, or chitosan to the plants through their cut stems, as expected if they utilize the octadecanoid pathway. The time course of jasmonic acid accumulation in tomato leaves in response to wounding was consistent with its proposed role in signaling proteinase inhibitor mRNA and protein synthesis. The cumulative evidence supports a model for the activation of defensive genes in plants in response to insect and pathogen attacks in which various elicitors generated at the attack sites activate the octadecanoid pathway via different recognition events to induce the expression of defensive genes in local and distal tissues of the plants.