Role of conducting systems in the transduction of long-distance stress signals

This review presents recent knowledge concerning integration between the reception of signals about abiotic or biotic stress conditions and the delivery of information to individual, even remote organs. In further consequence - physiological processes are affected e.g. pattern of biomass partitioning and growth. Strategy of optimal distribution of photosynthates increases the acclimation to stresses. Special attention is paid to the role of phloem and xylem as a superhighway, rapidly transmitting signals as well as products of stress gene expression: RNAs, proteins, transcription factors. The regulation of plant responses to adverse conditions is carried from the molecular to the whole organism level, not only by the modulation of gene expression, their Stimulation and silencing. but also by a post-transcriptional control. Various signalling molecules including hormones, salicylic acid and systemin, play a pivotal role in the regulation of plant response to stresses. They are trafficking into conducting bundles. Some physical factors such as hydraulic pressure and electrical signals, with a much his/her transmission velocity than chemical signalling molecules, also regulate the responses of plants to stresses. Both kinds of signals are propagated systemically through the plant body in a controlled way. in many cases by phloem or xylem. Several recent papers present the hypothesis of selective phloem loading and unloading especially of some macromolecular substances and viruses. Their transport may be surveillance also inside the sieve tubes.