Does the core circadian clock in the moss Physcomitrella patens (Bryophyta) comprise a single loop?

BMC Plant Biology

Research Article

Niclas Gyllenstrand¹  Harald Hedman²  Karl Holm²  Ulf Lagercrantz²  Thomas Källman² 

[1] Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden;Program in Evolutionary Functional Genomics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, SE-752 36, Uppsala, Sweden;

关键词: Circadian Clock;    Clock Gene;    Predict Protein Sequence;    Significant Sequence Homology;    Core Clock Gene;   

DOI  :  10.1186/1471-2229-10-109

 received in 2009-10-23, accepted in 2010-06-15,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundThe endogenous circadian clock allows the organism to synchronize processes both to daily and seasonal changes. In plants, many metabolic processes such as photosynthesis, as well as photoperiodic responses, are under the control of a circadian clock. Comparative studies with the moss Physcomitrella patens provide the opportunity to study many aspects of land plant evolution. Here we present a comparative overview of clock-associated components and the circadian network in the moss P. patens.ResultsThe moss P. patens has a set of conserved circadian core components that share genetic relationship and gene expression patterns with clock genes of vascular plants. These genes include Myb-like transcription factors PpCCA1a and PpCCA1b, pseudo-response regulators PpPRR1-4, and regulatory elements PpELF3, PpLUX and possibly PpELF4. However, the moss lacks homologs of AtTOC1, AtGI and the AtZTL-family of genes, which can be found in all vascular plants studied here. These three genes constitute essential components of two of the three integrated feed-back loops in the current model of the Arabidopsis circadian clock mechanism. Consequently, our results suggest instead a single loop circadian clock in the moss. Possibly as a result of this, temperature compensation of core clock gene expression appears to be decreased in P. patens.ConclusionsThis study is the first comparative overview of the circadian clock mechanism in a basal land plant, the moss P. patens. Our results indicate that the moss clock mechanism may represent an ancestral state in contrast to the more complex and partly duplicated structure of subsequent land plants. These findings may provide insights into the understanding of the evolution of circadian network topology.

【 授权许可】

Unknown   
© Holm et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.