Non-coding RNAs' partitioning in the evolution of photosynthetic organisms via energy transduction and redox signaling.

Ars longa, vita brevis -Hippocrates Chloroplasts and mitochondria are genetically semi-autonomous organelles inside the plant cell. These constructions formed after endosymbiosis and keep evolving throughout the history of life. Experimental evidence is provided for active non-coding RNAs (ncRNAs) in these prokaryote-like structures, and a possible functional imprinting on cellular electrophysiology by those RNA entities is described. Furthermore, updated knowledge on RNA metabolism of organellar genomes uncovers novel inter-communication bridges with the nucleus. This class of RNA molecules is considered as a unique ontogeny which transforms their biological role as a genetic rheostat into a synchronous biochemical one that can affect the energetic charge and redox homeostasis inside cells. A hypothesis is proposed where such modulation by non-coding RNAs is integrated with genetic signals regulating gene transfer. The implications of this working hypothesis are discussed, with particular reference to ncRNAs involvement in the organellar and nuclear genomes evolution since their integrity is functionally coupled with redox signals in photosynthetic organisms.