Light signalling mediated by phytochrome plays an important role in cold-induced gene expression through the C-repeat/dehydration responsive element (C/DRE) in Arabidopsis thaliana.
Low temperature induces a number of genes that encode the proteins promoting tolerance to freezing, mediated by ABA-dependent and ABA-independent pathways in plants. The cis-acting element called C/DRE is known to respond to low temperature independently of ABA action. To investigate the signalling and network of ABA-independent pathways, the transgenic Arabidopsis plants were generated containing several copies of the C/DRE derived from cor15a gene with a minimal promoter fused to a GUS reporter gene. The transgenic plants containing four copies of the C/DRE (4C/DRE-GUS) showed responsiveness to cold and drought treatments and were used for characterization of cold signalling and cross-talk. Cold-induced GUS expression was inhibited by okadaic acid at 1 nM, indicating that protein phosphatase 2A might act as a positive regulator. Light was shown to activate cold- and drought-induced GUS expression. Photo-reversibility of the GUS mRNA by red and far-red light with concomitant cold treatment suggests a role of phytochrome as a photoreceptor in mediating light signalling to activate the cold-induced gene expression through the C/DRE. Furthermore, GUS expression analysis in phyA or phyB or phyAphyB mutant backgrounds showed that phytochrome B is a primary photoreceptor responsible for the activation of cold-stress signalling in response to light. Light enhanced the induction kinetics of CBF1, 2, and 3 encoding the cognate transcription factors, and cor15a, in a consecutive manner compared to the dark condition in the cold, suggesting that the connection point between cold and light signalling mediated by phytochrome is at a higher step than the expression of CBF genes.
Kim
Hyoun-Joung
HJ
Kumho Life and Environmental Science Laboratory, Puk-Gu, Gwang-ju, Korea.
Kim
Yun-Kyoung
YK
Park
Jin-Young
JY
Kim
Jungmook
J
D000040:Abscisic Acid / Q000494:pharmacology; D000064:Acclimatization / Q000187:drug effects / Q000528:radiation effects; D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics; D003080:Cold Temperature; D004268:DNA-Binding Proteins / Q000235:genetics; D003624:Darkness; D004190:Disasters; D004237:Diuron / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects; D008027:Light; D009154:Mutation; D019319:Okadaic Acid / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010786:Photoreceptor Cells; D010834:Phytochrome / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D051939:Phytochrome B; D030821:Plants, Genetically Modified; D054648:Protein Phosphatase 2; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D012965:Sodium Chloride / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology; D015534:Trans-Activators / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics
D029681:Arabidopsis Proteins; C104387:CBF1 protein, Arabidopsis; C116166:COR15 protein, Arabidopsis; D004268:DNA-Binding Proteins; C114578:DREB1A protein, Arabidopsis; C497952:PHYB protein, Arabidopsis; D015534:Trans-Activators; D014157:Transcription Factors; D010834:Phytochrome; D051939:Phytochrome B; D019319:Okadaic Acid; D012965:Sodium Chloride; D000040:Abscisic Acid; D004237:Diuron; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2; D019311:Staurosporine