Involvement of reactive oxygen species and reactive nitrogen species in the wound response of Dasycladus vermicularis.

We investigated the signaling events involved in the wound response of the marine macroalga Dasycladus vermicularis, finding nitric oxide (NO) production in relation to injury. The addition of exogenous H2O2 to aliquots of injured algae accelerated the kinetics of NO production in the wounded region. Similarly, the addition of an NO donor caused an increase in detectable H2O2 around the site of injury. By wounding or incubating uninjured algae with an NO donor, peroxidase activity was enhanced. Based on the use of selected pharmacological probes, our results indicate that H2O2 production involves the upstream activation of signaling events similar to those observed in the physiology of higher plants.