Evidence for type II phytochrome-induced rapid signalling leading to cab::luciferase gene expression in tobacco cotyledons.
We studied the activation of cab gene expression by phytochrome-induced intercellular signalling and report insights into the mechanism of induction and outspread of a plant internal signal. By micro-beam irradiation techniques and use of a photon-imaging charge-coupled device (CCD) camera system we monitored cab::luciferase reporter gene expression in cotyledons of transgenic tobacco (Nicotiana tabacum L. cv. Xanthi) plants. We found that (i) the photoreceptor triggering intercellular signalling and reporter-gene expression is type II but not type I phytochrome, (ii) phytochrome in its far-red-absorbing (Pfr) form is necessary for the induction but not for the outspread of the signalling, (iii) red/far-red reversibility is restricted to the red-irradiated cells, and (iv) the phytochrome-induced signal spreads rapidly throughout the cotyledon and reaches its target cells within minutes.
Schütz
I
I
Hitachi Advanced Research Laboratory, Hatoyama, Saitama 350-0395, Japan. schuetz@mpiz-koeln.mpg.de
Furuya
M
M
D029681:Arabidopsis Proteins; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D018548:Cotyledon / Q000502:physiology / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D017930:Genes, Reporter; D007259:Infrared Rays; D007700:Kinetics; D008027:Light; D045342:Light-Harvesting Protein Complexes; D008156:Luciferases / Q000235:genetics; D010786:Photoreceptor Cells; D010834:Phytochrome / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D011993:Recombinant Fusion Proteins / Q000235:genetics; D015398:Signal Transduction; D014026:Nicotiana / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects
D029681:Arabidopsis Proteins; C423618:CAB2 protein, Arabidopsis; D002352:Carrier Proteins; D045342:Light-Harvesting Protein Complexes; D011993:Recombinant Fusion Proteins; D010834:Phytochrome; D008156:Luciferases