title: Circadian Oscillation of the Lettuce Transcriptome under Constant Light and Light-Dark Conditions.
abstract: Although, the circadian clock is a universal biological system in plants and it orchestrates important role of plant production such as photosynthesis, floral induction and growth, there are few such studies on cultivated species. Lettuce is one major cultivated species for both open culture and plant factories and there is little information concerning its circadian clock system. In addition, most of the relevant genes have not been identified. In this study, we detected circadian oscillation in the lettuce transcriptome using time-course RNA sequencing (RNA-Seq) data. Constant light (LL) and light-dark (LD) conditions were used to detect circadian oscillation because the circadian clock has some basic properties: one is self-sustaining oscillation under constant light and another is entrainment to environmental cycles such as light and temperature. In the results, 215 contigs were detected as common oscillating contigs under both LL and LD conditions. The 215 common oscillating contigs included clock gene-like contigs CCA1 (CIRCADIAN CLOCK ASSOCIATED 1)-like, TOC1 (TIMING OF CAB EXPRESSION 1)-like and LHY (LATE ELONGATED HYPOCOTYL)-like, and their expression patterns were similar to those of Arabidopsis. Functional enrichment analysis by GO (gene ontology) Slim and GO Fat showed that the GO terms of response to light stimulus, response to stress, photosynthesis and circadian rhythms were enriched in the 215 common oscillating contigs and these terms were actually regulated by circadian clocks in plants. The 215 common oscillating contigs can be used to evaluate whether the gene expression pattern related to photosynthesis and optical response performs normally in lettuce.
authors: Graduate School of Life and Environmental Sciences, Osaka Prefecture University Sakai, Japan.
authors: Takanobu
authors: T
authors: Higashi
authors: Graduate School of Life and Environmental Sciences, Osaka Prefecture University Sakai, Japan.
authors: Koh
authors: K
authors: Aoki
authors: Faculty of Agriculture, Ryukoku UniversityOtsu, Japan; Core Research for Evolutional Science and Technology - Japan Science and Technology AgencyKawaguchi, Japan; Center for Ecological Research, Kyoto UniversityOtsu, Japan.
authors: Atsushi J
authors: AJ
authors: Nagano
authors: Center for Ecological Research, Kyoto University Otsu, Japan.
authors: Mie N
authors: MN
authors: Honjo
authors: Graduate School of Engineering, Osaka Prefecture UniversitySakai, Japan; Precursory Research for Embryonic Science and Technology, Japan Science and Technology AgencyKawaguchi, Japan.
authors: Hirokazu
authors: H
authors: Fukuda
keywords: circadian clocks; enrichment; lettuce; oscillations; plant factories; transcriptome