Hilpert, Bernadette Bohlmann, Holger Camp, Roel op den Przybyla, Dominika Miersch, Otto Buchala, Antony J. Apel, Klaus 2001 Thionins are a group of antimicrobial polypeptides that form part of the plant's defense mechanism against pathogens. The <i>Thi</i> 2.1 thionin gene of <i>Arabidopsis thaliana</i> has been shown to be inducible by jasmonic acid (JA), an oxylipin-like hormone derived from oxygenated linolenic acid and synthesized via the octadecanoid pathway. The JA-dependent regulation of the <i>Thi</i> 2.1 gene has been exploited for setting up a genetic screen for the isolation of signal transduction mutants that constitutively express the <i>Thi</i> 2.1 gene. Ten <i>cet</i>-mutants have been isolated which showed a <i>c</i>onstitutive <i>e</i>xpression of the <i>t</i>hionin gene. Allelism tests revealed that they represent at least five different loci. Some mutants are dominant, others recessive, but all <i>cet</i> mutations behaved as monogenic traits when backcrossed with <i>Thi</i> 2.1-<i>GUS</i> plants. Some of the mutants overproduce JA and its bioactive precursor 12-oxophytodienoic acid (OPDA) up to 40-fold while others have the same low levels as the control wildtype plants. Two of the mutants showed a strong induction of both the salicylic acid (SA)- and the JA-dependent signaling pathways, while the majority seems to be affected only in the octadecanoid pathway. The <i>Thi</i> 2.1 thionin gene and the <i>Pdf</i> 1.2 defensin gene are activated independently, though both are regulated by JA. The <i>cet</i>-mutants, except for one, also show a spontaneous leaf cell necrosis, a reaction often associated with the systemic acquired resistance (SAR) pathway. application/pdf https://folia.unifr.ch/global/documents/299991 https://folia.unifr.ch/documents/299991/files/1_buchala_ics.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1046/j.1365-313X.2001.2641036.x info:eu-repo/semantics/openAccess License undefined The Plant Journal. - 2001, vol. 26, no. 4, p. 435-446 Thionins signal transduction mutants plant defense octadecanoid pathway info:eu-repo/classification/udc/57 Isolation and characterization of signal transduction mutants of Arabidopsis thaliana that constitutively activate the octadecanoid pathway and form necrotic microlesions http://purl.org/coar/resource_type/c_6501