New aspect of h(2)o(2) signaling.

Plant defense is based on a complex response triggered by unfavorable external impacts. The redox state of the cells and its temporal alteration, the oxidative burst, is an important regulatory element of this defense response. Data collected during the last years have caused us to change the previous, strongly simplified theory on signaling which had been based on a speculative, rather sequential mechanism. In the framework of signal transduction, H(2)O(2) signaling pathway(s) is/are only a special part of signal transduction but interacting with other pathways it/they influence the whole transducting system in several points. Our results show that in complexity and in basic regulatory mechanisms (transients, oscillation, tuning, signaling pattern) H(2)O(2) signaling is comparable with other pathways, of which we have more detailed cognition, and our present knowledge makes developing a new theory on this aspect necessary.