title: Identification of PaCOL1 and PaCOL2, two CONSTANS-like genes showing decreased transcript levels preceding short day induced growth cessation in Norway spruce.
abstract: In woody plants of the temperate zone short photoperiod (SD) leads to growth cessation. In angiosperms CONSTANS (CO) or CO-like genes play an important role in the photoperiodic control of flowering, tuberisation and shoot growth. To investigate the role of CO-like genes in photoperiodic control of shoot elongation in gymnosperms, PaCOL1 and PaCOL2 were isolated from Norway spruce. PaCOL1 encodes a 3.9kb gene with a predicted protein of 444 amino acids. PaCOL2 encodes a 1.2kb gene with a predicted protein of 385 amino acids. Both genes consist of two exons and have conserved domains found in other CO-like genes; two zinc finger domains, a CCT and a COOH domain. PaCOL1 and PaCOL2 fall into the group 1c clade of the CO-like genes, and are thus distinct from Arabidopsis CO that belongs to group 1a. Transcript levels of both PaCOL-genes appear to be light regulated, an increasing trend was observed upon transition from darkness to light, and a decreasing trend during darkness. The increasing trend at dawn was observed both in needles and shoot tips, whereas the decreasing trend in darkness was most prominent in shoot tips, and limited to the late part of the dark period in needles. The transcript levels of both genes decreased significantly in both tissues under SD prior to growth cessation and bud formation. This might suggest an involvement in photoperiodic control of shoot elongation or might be a consequence of regulation by light.
authors.affiliation: Norwegian University of Life Sciences, Department of Plant and Environmental Sciences, P.O. Box 5003, N-1432 As, Norway.
authors.forename: Anna
authors.initials: A
authors.lastname: Holefors
authors.forename: Lars
authors.initials: L
authors.lastname: Opseth
authors.forename: Anne Katrine
authors.initials: AK
authors.lastname: Ree Rosnes
authors.forename: Linda
authors.initials: L
authors.lastname: Ripel
authors.forename: Lars
authors.initials: L
authors.lastname: Snipen
authors.forename: Carl Gunnar
authors.initials: CG
authors.lastname: Fossdal
authors.forename: Jorunn E
authors.initials: JE
authors.lastname: Olsen
mesh_terms: D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics; D003624:Darkness; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018745:Genome, Plant; D008027:Light; D008969:Molecular Sequence Data; D017440:Photoperiod; D028222:Picea / Q000235:genetics* / Q000254:growth & development; D010940:Plant Proteins / Q000145:classification / Q000235:genetics*; D016415:Sequence Alignment; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; C092776:CONSTANS protein, Arabidopsis; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D014157:Transcription Factors