Conserved Function of Core Clock Proteins in the Gymnosperm Norway Spruce (Picea Abies L. Karst)

PLoS One. 2013;8(3):e60110. doi: 10.1371/journal.pone.0060110. Epub 2013 Mar 28.

Abstract

From studies of the circadian clock in the plant model species Arabidopsis (Arabidopsis thaliana), a number of important properties and components have emerged. These include the genes CIRCADIAN CLOCK ASSOCIATED 1 (CCA1), GIGANTEA (GI), ZEITLUPE (ZTL) and TIMING OF CAB EXPRESSION 1 (TOC1 also known as PSEUDO-RESPONSE REGULATOR 1 (PRR1)) that via gene expression feedback loops participate in the circadian clock. Here, we present results from ectopic expression of four Norway spruce (Picea abies) putative homologs (PaCCA1, PaGI, PaZTL and PaPRR1) in Arabidopsis, their flowering time, circadian period length, red light response phenotypes and their effect on endogenous clock genes were assessed. For PaCCA1-ox and PaZTL-ox the results were consistent with Arabidopsis lines overexpressing the corresponding Arabidopsis genes. For PaGI consistent results were obtained when expressed in the gi2 mutant, while PaGI and PaPRR1 expressed in wild type did not display the expected phenotypes. These results suggest that protein function of PaCCA1, PaGI and PaZTL are at least partly conserved compared to Arabidopsis homologs, however further studies are needed to reveal the protein function of PaPRR1. Our data suggest that components of the three-loop network typical of the circadian clock in angiosperms were present before the split of gymnosperms and angiosperms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CLOCK Proteins / genetics
  • Cycadopsida / genetics
  • Cycadopsida / metabolism*
  • Gene Expression Regulation, Plant / genetics
  • Gene Expression Regulation, Plant / physiology
  • Phylogeny
  • Picea / classification
  • Picea / genetics
  • Picea / metabolism*
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*

Substances

  • Plant Proteins
  • CLOCK Proteins

Grant support

AK has received financial support from the Royal Swedish Academy of Agriculture and Forestry and NG was supported by the Carl Trygger Foundation. Financial support to UL was provided by the Swedish Research Council and the Swedish Research Council FORMAS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.