9/14
当研究室の研究成果が、研究成果として科学誌のNATURE誌に受理されました。タイトルと要旨は以下の通りです。
-Title-
A blue-light photoreceptor mediates the feedback regulation of photosynthesis
-Authors-
Dimitris Petroutsos*, Ryutaro Tokutsu*, Shinichiro Maruyama, Serena Flori, Andre Greiner, Leonardo Magneschi, Loic Cusant, Tilman Kottke, Maria Mittag, Peter Hegemann, Giovanni Finazzi & Jun Minagawa
*These authors contributed equally to this work.
-Abstract-
In plants and algae, light serves both as the energy source for photosynthesis and a biological signal that triggers cellular responses via specific sensory photoreceptors. Red light is perceived by bilin-containing phytochromes and blue light by the flavin-containing cryptochromes and/or phototropins (PHOTs), the latter containing two photosensory light, oxygen, or voltage (LOV) domains. Photoperception spans several orders of light intensity, ranging from far below the threshold for photosynthesis to values beyond the capacity of photosynthetic CO2 assimilation. Excess light may cause oxidative damage and cell death, processes prevented by enhanced thermal dissipation via high-energy quenching (qE), a key photoprotective response. Here we show the existence of a molecular link between photoreception, photosynthesis, and photoprotection in the green alga Chlamydomonas reinhardtii. We show that PHOT controls qE by inducing the expression of the qE effector protein LHCSR3 (light-harvesting complex stress-related protein 3) in high light intensities. This control requires blue-light perception by LOV domains on PHOT, LHCSR3 induction through PHOT kinase, and light dissipation in photosystem II via LHCSR3. Mutants deficient in the PHOT gene display severely reduced fitness under excessive light conditions, indicating that the sensing, utilization, and dissipation of light is a concerted process that plays a vital role in microalgal acclimation to environments of variable light intensities.
-簡単な解説-
青色光受容体であるフォトトロピンは、これまで光合成にはそこまで関係ないのではと言われていました。しかし、今回の研究で、そのフォトトロピンがqEクエンチングに決定的な役割を果たしていることが明らかになりました。
