Clock and temperature- mediated gene expression in nothofagus pumilio, one of the dominant woody species of the southernmost terrestrial ecosystems of the world.

ESTRAVIS BARCALÁ, M.; MARCHELLI, P; HEER, K.; ZIEGENHAGEN, B; BELLORA, N.; ARANA, M.V.

Santiago

Workshop; Signat workshop on environmental regulation of plant development.; 2017

SIGNAT

In this work, we show data related to the characterization of the circadian clock and the influence ofwarm temperatures (34°C) on global patterns of gene expression in Nothofagus pumilio, the mostabundant tree species of South American Patagonian forests. We report the isolation of centraloscillator genes, and the study of the expression of two of them (TOC1 and LHY) in diurnal andcircadian conditions at different temperatures. Through the analysis of RNA-seq experiments fromplants grown in circadian conditions (entrainment: 12h light/12h darkness, sampling in free runningconditions: continuous light, at 20° or 34°C at two moments of the day: ZT48=subjective dawn,ZT60=subjective dusk), we studied the effect of warm temperatures on the transcriptome of N.pumilio. We found evidence of the existence of at least two pathways by which warm temperaturesaffect gene expression. One would be triggered by an effect on the circadian clock-mediated generegulation, in which warm temperatures down-regulate the clock-mediated promotion of growthrelatedgenes at subjective dawn as well as the clock-mediated promotion of metabolic genes atsubjective dusk. The second pathway would be triggered by the temperature itself ? independentlyof its influence on the clock- and includes the temperature-mediated promotion of genes related tojasmonic acid/stress responses in conjunction with the down-regulation of genes related withphotosynthesis.Given this species? wide distribution range (36° to 55°S), studies related with the analysis of the N.pumilio circadian clock function and its interaction with temperature constitute an interestingstrategy to address adaptation and plasticity of woody plants to different thermic and photoperiodicenvironments, such as those occurring across latitude.Acknowledgements. Agencia Nacional de Promoción Científica y Tecnológica: PICT 2011-2250;CONICET: PIP 11220150100237CO-1; INTA: PNFOR 1104064; MINCYT-DAAD Bilateral ProjectDA13/06; European Union Seventh Framework Program FP7: Trees4Future (P113).