RT Journal Article
SR Electronic
T1 Uncoupling PR Gene Expression from NPR1 and Bacterial Resistance: Characterization of the Dominant Arabidopsis <em>cpr6-1</em> Mutant
JF The Plant Cell
JO Plant Cell
FD American Society of Plant Biologists
SP 557
OP 569
DO 10.1105/tpc.10.4.557
VO 10
IS 4
A1 Clarke, Joseph D.
A1 Liu, Yidong
A1 Klessig, Daniel F.
A1 Dong, Xinnian
YR 1998
UL http://www.plantcell.org/content/10/4/557.abstract
AB In Arabidopsis, NPR1 mediates the salicylic acid (SA)–induced expression of pathogenesis-related (PR) genes and systemic acquired resistance (SAR). Here, we report the identification of another component, CPR6, that may function with NPR1 in regulating PR gene expression. The dominant CPR6-1 mutant expresses the SA/NPR1–regulated PR genes (PR-1, BGL2, and PR-5) and displays enhanced resistance to Pseudomonas syringae pv maculicola ES4326 and Peronospora parasitica Noco2 in the absence of SAR induction. cpr6-1–induced PR gene expression is not suppressed in the cpr6-1 npr1-1 double mutant but is suppressed when SA is removed by salicylate hydroxylase. Thus, constitutive PR gene expression in cpr6-1 requires SA but not NPR1. In addition, resistance to P. s. maculicola ES4326 is suppressed in the cpr6-1 npr1-1 double mutant, despite expression of PR-1, BGL2, and PR-5. Resistance to P. s. maculicola ES4326 must therefore be accomplished through unidentified antibacterial gene products that are regulated through NPR1. These results show that CPR6 is an important regulator of multiple signal transduction pathways involved in plant defense.