Open AccessIsolation and Characterization of Broad-Spectrum Disease-Resistant Arabidopsis Mutants
Author(s) -
Klaus Maleck,
Urs Neuenschwander,
Rebecca Cade,
Robert A. Dietrich,
Jeffery L. Dangl,
John Ryals
Publication year - 2002
Publication title -
genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.792
H-Index - 246
eISSN - 1943-2631
pISSN - 0016-6731
DOI - 10.1093/genetics/160.4.1661
Subject(s) - biology , mutant , pseudomonas syringae , arabidopsis , mutagenesis , genetics , gene , systemic acquired resistance , transgene , reporter gene , forward genetics , microbiology and biotechnology , gene expression
To identify Arabidopsis mutants that constitutively express systemic acquired resistance (SAR), we constructed reporter lines expressing the firefly luciferase gene under the control of the SAR-inducible PR-1 promoter (PR-1/luc). After EMS mutagenesis of a well-characterized transgenic line, we screened 250,000 M(2) plants for constitutive expression of the reporter gene in vivo. From a mutant collection containing several hundred putative mutants, we concentrated on 16 mutants lacking spontaneous hypersensitive response (HR) cell death. We mapped 4 of these constitutive immunity (cim) mutants to chromosome arms. Constitutive expression of disease resistance was established by analyzing responses to virulent Peronospora parasitica and Pseudomonas syringae strains, by RNA blot analysis for endogenous marker genes, and by determination of salicylic acid levels in the mutants. The variety of the cim phenotypes allowed us to define distinct steps in both the canonical SAR signaling pathway and a separate pathway for resistance to Erysiphe cichoracearum, active in only a subset of the mutants.