FIGURE 1.

The impact of nitric oxide on salicylic acid, jasmonate (and ethylene signaling cascades. Schematic versions of salicylic acid (SA), jasmonate (JA), and ethylene (ET) signaling cascade. Biosynthetic enzymes are represented as gray ovals and signaling components are gray rectangles. Abbreviations in the jasmonate biosynthetic pathway are as follows: LOX, lipoxygenase; AOC, allene oxide cyclase; OPR, oxo-phytodienoate reductase; for the ethylene biosynthetic pathway: ACS, 1-aminocyclopropane-1-carboxylic acid synthase; ACO, 1-aminocyclopropane-1-carboxylic acid oxidase. Genes and their regulatory promoters are represented as open boxes. For details of signaling cascades, see main text. The known NO-regulated steps are indicated: green arrows indicating that NO has a promontory effects via induction of gene transcription; S-nitrosylative steps are indicated via a solid black bar and whether this promotes (green arrows) or inhibit a signaling (red bar) step. Note that for and ACO and ACS4, the effect of S-nitrosylation has yet to be determined.