GSE123654
Expansion of the circadian transcriptome in Brassica rapa supports genome wide diversification of homeolog gene expression patterns
Following divergence from Arabidopsis thaliana, Brassica rapa underwent a whole genome triplication followed by extensive genome fractionation. Preferential retention of circadian clock genes suggest that expansion of the circadian network may play an important role during B. rapa domestication. To characterize the circadian transcriptome network, RNA-seq was performed in the B. rapa oil-type variety R500 following photocycle and thermocycle circadian time courses. The photocycle (LDHH) time course consisted of growing plants for 15 days at 20°C under a 12h light/12h dark photoperiod and transfering plants to constant light and 20°C 24h prior to harvesting leaf tissue every 2h for 48h starting at ZT24 with 2 biological replicates at every time point. The thermocycle (LLHC) time course consisted of growing plants for 15 days under constant light with a 12h 20°C/12h 10°C thermoperiod and transfering plants to constant light and 20°C 24h prior to harvesting leaf tissue every 2h for 48h starting at ZT24 with 2 biological replicates at every time point. Overall design: Brassica rapa subsp. trilocularis (R500) plants were grown under photocycle (LDHH) 12h light at 20°C/12h dark at 10°C and thermocycle (LLHC) 12h light at 20°C/12h light at 10°C conditions for 15 days after sowing (DAS) before transfering to constant light and 20°C (LLHH). Starting 24h after transfer to LLHH, leaf tissue was collected every 2h for 48h. We collected 2 replicates for every time point.