Abstract
Nitric oxide (NO) is a ubiquitous signaling molecule involved in diverse physiological process. Despite the wealth of information gathered over the last decade, the mechanisms of NO action are poorly known. We now assess the possibility that nitrated cGMP (8-nitro-cGMP) functions in guard cell signaling. At previous meeting, we reported that nitrated cGMP induce stomatal closure. At this meeting, to assess the possibility that nitration of cGMP occur in guard cells, immunocytochemical analyses were performed using a monoclonal antibody against 8-nitro-cGMP. We detected strong fluorescence in guard cells treated with ABA and NO donor. Nitric oxide synthase inhibitor diminished ABA-induced immunofluorescence and NO-scavenger diminished the immunofluorescence induced by ABA and NO. Furthermore, guanylate cyclase inhibitor also cause decrease of ABA- and NO-induced immunofluorescence. These results indicate that 8-nitro-cGMP is formed in an NO- and cGMP-dependent manner.
