REVEILLE2 is a cold-induced component of the circadian system that regulates how Arabidopsis thaliana responds to night-time chilling (rve2-2 mutant)

Dataset: RNA-seq diel and temperature time series experiment of rve2-2 mutant.All plant material was the Columbia (Col-0) ecotype. The rve2-2 mutant was obtained from GABI-Kat and homozygous mutant lines were selected and characterised. All plants were harvested 5 weeks after sowing. The tissue was immediately frozen in liquid nitrogen and stored at -80 degrees Celsius until further use. Plants were harvested at 3 h intervals over 24 h at 20 degrees Celsius and on days 1 and 4 after transfer to 4 degrees Celsius , with one additional time point at 7.5h after transfer to 4 degrees Celsius on day 1. Transfer to 4 degrees Celsius was initiated at dusk.Project SummarySplicing mediated reversals of the relative abundances of transcript isoforms of the same gene - 'isoform switching' - is a striking feature of plants' rapid response to cooling. We find the flip-flop dynamism of the REVEILLE2 isoform switch particularly striking; it is detectable on the minute-timescale and unusually is an 'off:on' switch with the shift to translatable transcript message evident during the transition to cool nights.The physiological relevance of this circadian clock cold-switch was explored using molecular genetic approaches centred around a newly characterised T-DNA insertion line, rve2-2, that is unable to cold-switch.We demonstrate altered cooling-associated rhythmic behaviour in plants bearing a clock promoter reporter (CCA1::LUC) in the rve2-2 background. RNA-seq experiments with rve2-2 identify potential RVE2 target genes and temporal profiling show they comprise a cascade of gene expression initiated shortly after peak RVE2 expression mid-nocturnal phase extending to the imminent dawn. Surprisingly we find a subset of chloroplast-encoded candidates with modified expression in rve2-2 and consequently we find altered photosynthetic capacity a rve2-2 characteristic.The RVE2 cold switch extends our understanding of plants' rapid response to cooling. We propose that RVE2 integrates nocturnal temperature with priming plants' photosynthetic capacity in anticipation of the break of the day.