Identification of a dual orange/far-red and blue light photoreceptor from an oceanic green picoplankton

Abstract

Photoreceptors are conserved in green algae to land plants and regulate various developmental stages. In the ocean, blue light penetrates deeper than red light, and blue-light sensing is key to adapting to marine environments. Here, a search for blue-light photoreceptors in the marine metagenome uncover a chimeric gene composed of a phytochrome and a cryptochrome (Dualchrome1, DUC1) in a prasinophyte, Pycnococcus provasolii. DUC1 detects light within the orange/far-red and blue spectra, and acts as a dual photoreceptor. Analyses of its genome reveal the possible mechanisms of light adaptation. Genes for the light-harvesting complex (LHC) are duplicated and transcriptionally regulated under monochromatic orange/blue light, suggesting P. provasolii has acquired environmental adaptability to a wide range of light spectra and intensities.

The World of Algae Reveals a Broad Variety of Cryptochrome Properties and Functions

“…Recently, a new type of photoreceptor from the marine picoalga Pp was discovered in metagenome data of ocean picoplankton, named dualchrome (DUC1, Figures 2 , 3 ). DUC1 bears a fusion of a phytochrome and a plant CRY ( Makita et al, 2021 ) and was not found in any other alga or other organisms so far.…”

“… Cryptochrome categories in algae ( Juhas et al, 2014 ; Kottke et al, 2017 ; Makita et al, 2021 ; Rredhi et al, 2021 ). A representative member of each of the five known categories is shown, starting with the classical plant cryptochrome of the green flagellate alga Chlamydomonas reinhardtii (Cr pCRY) and its long C-terminal extension.…”

“…Colored circles indicate the numbers (presented in each circle) and representatives of different types of CRYs within the presented species (green, plant CRY; blue, plant-like CRY; orange, animal-like CRY/CPF1; purple, CRY-DASH and CRY-DASH-like; magenta, dualchrome; gray, CRY(s) that are currently not assigned to the former groups; “?,” indicating that there may be further potential CRY(s) in this organism that have not been identified so far). Information for the presented data was taken from the following references: Cyanidioschyzon merolae (Cm; Brawley et al, 2017 ), Porphyra umbilicalis (Pum; Brawley et al, 2017 ), Saccharina japonica (Sj; Deng et al, 2012 ; Yang et al, 2020 ), Phaeodactylum tricornutum (Pt; Juhas et al, 2014 ; Oliveri et al, 2014 ; Fortunato et al, 2015 ), Karenia brevis (Kb; Brunelle et al, 2007 ), Ostreococcus tauri (Ot; Heijde et al, 2010 ; Kottke et al, 2017 ), Pycnococcus provasolii (Pp; Makita et al, 2021 ), Chlamydomonas reinhardtii (Cr; Beel et al, 2012 ; Kottke et al, 2017 ), Volvox carteri (Vc; Kottke et al, 2017 ) and Arabidopsis thaliana (At; Chaves et al, 2011 ). Please note that three putative CRY-DASHs are predicted for Cm in the analysis of Asimgil and Kavakli (2012) .…”

“…Localization of the novel type dualchrome was analyzed heterologously in tobacco cells in fusion with GFP. It was primarily found in the nucleus and its localization was not changed by light treatment ( Makita et al, 2021 ).…”

“…For example, LOV domains were found within one protein together with different DNA-binding domains such as a homeobox or a heat shock factor domain or with signal-transduction motifs (e.g., an EF-hand; Coesel et al, 2021 ). A new type of dual cryptochrome that is fused to another photoreceptor was also found in these genomes ( Makita et al, 2021 ) and is included in this review.…”