Cryptochrome 1a of tomato mediates long-distance signaling of soil water deficit.

Although the blue light photoreceptors cryptochromes mediate the expression of genes related to reactive oxygen species, whether cryptochrome 1a (cry1a) regulates local and long-distance signaling of water deficit in tomato (Solanum lycopersicum L.) is unknown. Thus the cry1a tomato mutant and its wild-type (WT) were reciprocally grafted (WT/WT; cry1a/cry1a; WT/cry1a; cry1a/WT; as scion/rootstock) or grown on their own roots (WT and cry1a) under irrigated and water deficit conditions. Plant growth, pigmentation, oxidative stress, water relations, stomatal characteristics and leaf gas exchange were measured. WT and cry1a plants grew similarly under irrigated conditions, whereas cry1a plants had less root biomass and length and higher tissue malondialdehyde concentrations under water deficit. Despite greater oxidative stress, cry1a maintained chlorophyll and carotenoid concentrations in drying soil. Lower stomatal density of cry1a likely increased its leaf relative water content (RWC). In grafted plants, scion genotype largely determined shoot and root biomass accumulation irrespective of water deficit. In chimeric plants grown in drying soil, cry1a rootstocks increased RWC while WT rootstocks maintained photosynthesis of cry1a scions. Manipulating tomato CRY1a may enhance plant drought tolerance by altering leaf pigmentation and gas exchange during soil drying via local and long-distance effects.

ROS signaling pathways and biological rhythms: perspectives in crustaceans.

This work reviews concepts regarding the endogenous circadian clock and the relationship between oxidative stress (OS), light and entrainment in different organisms including crustaceans, particularly crayfish. In the first section, the molecular control of circadian rhythms in invertebrates, particularly in Drosophila, is reviewed, and this model is contrasted with recent reports on the circadian genes and proteins in crayfish. Second, the redox mechanisms and signaling pathways that participate in the entrainment of the circadian clock in different organisms are reviewed. Finally, the light signals and transduction pathways involved in the entrainment of the circadian clock, specifically in relation to cryptochromes (CRYs) and their dual role in the circadian clock of different animal groups and their possible relationship to the circadian clock and redox mechanisms in crustaceans is discussed. The relationship between metabolism, ROS signals and transcription factors, such as HIF-1 alpha in crayfish, as well as the possibility that HIF-1 alpha participates in the regulation of circadian control genes (ccgs) in crustaceans is discussed.