Diatom Phytochromes Reveal the Existence of Far-Red-Light-Based Sensing in the Ocean.
Plant Cell
; 28(3): 616-28, 2016 Mar.
Article
em En
| MEDLINE
| ID: mdl-26941092
ABSTRACT
The absorption of visible light in aquatic environments has led to the common assumption that aquatic organisms sense and adapt to penetrative blue/green light wavelengths but show little or no response to the more attenuated red/far-red wavelengths. Here, we show that two marine diatom species, Phaeodactylum tricornutum and Thalassiosira pseudonana, possess a bona fide red/far-red light sensing phytochrome (DPH) that uses biliverdin as a chromophore and displays accentuated red-shifted absorbance peaks compared with other characterized plant and algal phytochromes. Exposure to both red and far-red light causes changes in gene expression in P. tricornutum, and the responses to far-red light disappear in DPH knockout cells, demonstrating that P. tricornutum DPH mediates far-red light signaling. The identification of DPH genes in diverse diatom species widely distributed along the water column further emphasizes the ecological significance of far-red light sensing, raising questions about the sources of far-red light. Our analyses indicate that, although far-red wavelengths from sunlight are only detectable at the ocean surface, chlorophyll fluorescence and Raman scattering can generate red/far-red photons in deeper layers. This study opens up novel perspectives on phytochrome-mediated far-red light signaling in the ocean and on the light sensing and adaptive capabilities of marine phototrophs.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Fitocromo
/
Plantas
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Diatomáceas
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Transdução de Sinal Luminoso
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article