RT Journal Article SR Electronic T1 Molecular and transcriptional structure of the petal and leaf circadian clock in Petunia hybrida JF bioRxiv FD Cold Spring Harbor Laboratory SP 641639 DO 10.1101/641639 A1 Marta I. Terry A1 Marta Carrera-Alesina A1 Julia Weiss A1 Marcos Egea-Cortines YR 2019 UL http://biorxiv.org/content/early/2019/05/17/641639.abstract AB The plant circadian clock coordinates environmental signals with internal processes. We characterized the genomic and transcriptomic structure of the Petunia hybrida W115 clock in leaves and petals. We found three levels of evolutionary differences. First, PSEUDO-RESPONSE REGULATORS PhPRR5a, PhPRR5b, PhPRR7a, PhPRR7b, and GIGANTEA PhGI1 and PhGI2, differed in gene structure including exon number and deletions including the CCT domain of the PRR family. Second, leaves showed preferential day expression while petals tended to display night expression. Under continuous dark, most genes were delayed in leaves and petals. Importantly, photoperiod sensitivity of gene expression was tissue specific as TIMING OF CAB EXPRESSION PhNTOC1 was affected in leaves but not in petals, and PhPRR5b, PhPRR7b and the ZEITLUPE ortholog CHANEL, PhCHL, were modified in petals but not leaves. Third, we identified a strong transcriptional noise at different times of the day, and high robustness at dawn in leaves and dusk in petals, coinciding with the coordination of photosynthesis and scent emission. Our results indicate multilayered evolution of the Petunia clock including gene structure, number of genes and transcription patterns. The major transcriptional reprogramming of the clock in petals, with night expression may be involved in controlling scent emission in the dark.Highlight The petunia leaf circadian clock shows maxima during the day while petal clock does it during the night. Reaction to dark is organ specific.CCTCONSTANS, CONSTANS-like, and TIMING OF CAB EXPRESSION 1 domainCtCycle thresholdPaxiNPetunia axillarisPhACTACTINPhELF4EARLY FLOWERING 4PhFKFFLAVIN-BINDING KELCH REPEAT F-BOXPhGI1GIGANTEA 1PhGI2GIGANTEA 2PhLHYLATE ELONGATED HYPOCOTYLPhPRRs (PhPRR3, PhPRR5a, PhPRR5b, PhPRR7a, PhPRR7b and PhPRR9)PSEUDO-RESPONSE REGULATORSPhTOC1TIMING OF CAB EXPRESSION 1PhCHLCHANEL (ZEITLUPE)PhPetunia hybridaPinfS6Petunia inflataREGResponse regulatory domainZTZeitgeber time.