The regulation of circadian period by phototransduction pathways in Arabidopsis

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Science  24 Feb 1995:
Vol. 267, Issue 5201, pp. 1163-1166
DOI: 10.1126/science.7855596


Transgenic Arabidopsis plants expressing a luciferase gene fused to a circadian-regulated promoter exhibited robust rhythms in bioluminescence. The cyclic luminescence has a 24.7-hour period in white light but 30- to 36-hour periods under constant darkness. Either red or blue light shortened the period of the wild type to 25 hours. A phytochrome-deficient mutation lengthened the period in continuous red light but had little effect in continuous blue light, whereas seedlings carrying mutations that activate light-dependent pathways in darkness maintained shorter periods in constant darkness. These results suggest that both phytochrome- and blue light-responsive photoreceptor pathways control the period of the circadian clock.

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