Circadian Control of Chloroplast Transcription by a Nuclear-Encoded Timing Signal

• Autores: Kenyu Ishii, Jelena Kusakina, Zeenat B. Noordally
• Localización: Science, ISSN 0036-8075, Vol. 339, Nº 6125, 2013, págs. 1317-1319
• Idioma: inglés
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• Resumen

  • Circadian timekeeping in plants increases photosynthesis and productivity. There are circadian oscillations in the abundance of many chloroplast-encoded transcripts, but it is not known how the circadian clock regulates chloroplast transcription or the photosynthetic apparatus. We show that, in Arabidopsis, nuclear-encoded SIGMA FACTOR5 (SIG5) controls circadian rhythms of transcription of several chloroplast genes, revealing one pathway by which the nuclear-encoded circadian oscillator controls rhythms of chloroplast gene expression. We also show that SIG5 mediates the circadian gating of light input to a chloroplast-encoded gene. We have identified an evolutionarily conserved mechanism that communicates circadian timing information between organelles with distinct genetic systems and have established a new level of integration between eukaryotic circadian clocks and organelles of endosymbiotic origin.