Isolation and characterization of signal transduction mutants of Arabidopsis thaliana that constitutively activate the octadecanoid pathway and form necrotic microlesions

Citation
B. Hilpert et al., Isolation and characterization of signal transduction mutants of Arabidopsis thaliana that constitutively activate the octadecanoid pathway and form necrotic microlesions, PLANT J, 26(4), 2001, pp. 435-446
Citations number
54
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Plant Sciences","Animal & Plant Sciences
Journal title
PLANT JOURNAL
ISSN journal
0960-7412 → ACNP
Volume
26
Issue
4
Year of publication
2001
Pages
435 - 446
Database
ISI
SICI code
0960-7412(200105)26:4<435:IACOST>2.0.ZU;2-Y
Abstract
Thionins are a group of antimicrobial polypeptides that form part of the pl ant's defense mechanism against pathogens. The Thi 2.1 thionin gene of Arab idopsis thaliana has been shown to be inducible by jasmonic acid (JA), an o xylipin-like hormone derived from oxygenated linolenic acid and synthesized via the octadecanoid pathway. The JA-dependent regulation of the Thi 2.1 g ene has been exploited for setting up a genetic screen for the isolation of signal transduction mutants that constitutively express the Thi 2.1 gene. Ten cet-mutants have been isolated which showed a constitutive expression o f the thionin gene. Allelism tests revealed that they represent at least fi ve different loci. Some mutants are dominant, others recessive, but all cet mutations behaved as monogenic traits when backcrossed with Thi 2.1-GUS pl ants. Some of the mutants overproduce JA and its bioactive precursor 12-oxo phytodienoic acid (OPDA) up to 40-fold while others have the same low level s as the control wildtype plants. Two of the mutants showed a strong induct ion of both the salicylic acid (SA)- and the JA-dependent signaling pathway s, while the majority seems to be affected only in the octadecanoid pathway . The Thi 2.1 thionin gene and the Pdf 1.2 defensin gene are activated inde pendently, though both are regulated by JA. The cet-mutants, except for one , also show a spontaneous leaf cell necrosis, a reaction often associated w ith the systemic acquired resistance (SAR) pathway.