PT  - JOURNAL ARTICLE
AU  - Mandal, Mihir Kumar
AU  - Chandra-Shekara, A.C.
AU  - Jeong, Rae-Dong
AU  - Yu, Keshun
AU  - Zhu, Shifeng
AU  - Chanda, Bidisha
AU  - Navarre, Duroy
AU  - Kachroo, Aardra
AU  - Kachroo, Pradeep
TI  - Oleic Acid–Dependent Modulation of NITRIC OXIDE ASSOCIATED1 Protein Levels Regulates Nitric Oxide–Mediated Defense Signaling in <em>Arabidopsis</em>
AID  - 10.1105/tpc.112.096768
DP  - 2012 Apr 01
TA  - The Plant Cell
PG  - 1654--1674
VI  - 24
IP  - 4
4099  - http://www.plantcell.org/content/24/4/1654.short
4100  - http://www.plantcell.org/content/24/4/1654.full
SO  - Plant Cell2012 Apr 01; 24
AB  - The conserved cellular metabolites nitric oxide (NO) and oleic acid (18:1) are well-known regulators of disease physiologies in diverse organism. We show that NO production in plants is regulated via 18:1. Reduction in 18:1 levels, via a genetic mutation in the 18:1-synthesizing gene SUPPRESSOR OF SA INSENSITIVITY OF npr1-5 (SSI2) or exogenous application of glycerol, induced NO accumulation. Furthermore, both NO application and reduction in 18:1 induced the expression of similar sets of nuclear genes. The altered defense signaling in the ssi2 mutant was partially restored by a mutation in NITRIC OXIDE ASSOCIATED1 (NOA1) and completely restored by double mutations in NOA1 and either of the nitrate reductases. Biochemical studies showed that 18:1 physically bound NOA1, in turn leading to its degradation in a protease-dependent manner. In concurrence, overexpression of NOA1 did not promote NO-derived defense signaling in wild-type plants unless 18:1 levels were lowered. Subcellular localization showed that NOA1 and the 18:1 synthesizing SSI2 proteins were present in close proximity within the nucleoids of chloroplasts. Indeed, pathogen-induced or low-18:1-induced accumulation of NO was primarily detected in the chloroplasts and their nucleoids. Together, these data suggest that 18:1 levels regulate NO synthesis, and, thereby, NO-mediated signaling, by regulating NOA1 levels.GlossaryFAfatty acid18:1oleic acid18:0stearic acidSACPDstearoyl-ACP desaturaseG3Pglycerol-3-phosphateNOnitric oxideNRnitrate reductaseSNPsodium nitroprussideDAF-FM DA4-amino-5-methylamino-2,7-difluorofluorescein diacetateDEA-NONOate2-(N,N-diethylamino)-diazenolate-2-oxideCol-0Columbia-0SAsalicylic acidH2O2hydrogen peroxideGFPgreen fluorescent proteinDAPI4′,6-diamidino-2-phenylindoleMEPmethylerythritol phosphateGCgas chromatographyCFPcyan fluorescent proteinRFPred fluorescent protein