Photoperiod-dependent regulation of cell growth by PpCCA1a and PpCCA1b genes encoding single-myb clock proteins in the moss Physcomitrella patens.
The PpCCA1a and PpCCA1b genes of the moss Physcomitrella patens are functional homologs of the Arabidopsis thaliana circadian clock genes CCA1/LHY. We made use of disruptant lines for PpCCA1a and/or PpCCA1b to elucidate the physiological significance of these genes in the growth of moss protonemal tissue under alternating day/night cycles. Protonemal cells of the double disruptant line, carrying neither of the two genes, grew faster than those of the wild-type plant (WT) in long days (LD), whereas no difference in the growth rate was detected between them in short days (SD). The double disruptant line also showed day length-dependent phenotypic changes in the PpCCA1b promoter activity: the diurnal profile of bioluminescence from the P(CCA1b)::LUC+ reporter strain was more significantly affected in LD than in SD. These observations are the first demonstration of a physiological function of the circadian clock in non-angiosperm land plants, and are consistent with recent findings that the clock controls hypocotyl elongation of A. thaliana in a photoperiod-dependent manner.
Okada
Ryo
R
Graduate School of Information Science, Nagoya University, Furo-cho. Chikusa-ku, Nagoya 464-8601, Japan.
Satbhai
Santosh B
SB
Aoki
Setsuyuki
S
D017360:Arabidopsis; D029681:Arabidopsis Proteins; D019068:Bryopsida / Q000235:genetics* / Q000254:growth & development*; D056926:CLOCK Proteins / Q000235:genetics* / Q000378:metabolism; D049109:Cell Proliferation; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D009154:Mutation / Q000235:genetics; D017440:Photoperiod; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D014157:Transcription Factors
D029681:Arabidopsis Proteins; C114425:CCA1 protein, Arabidopsis; D018744:DNA, Plant; D010940:Plant Proteins; D014157:Transcription Factors; D056926:CLOCK Proteins