pubmed.ncbi.nlm.nih.gov

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

  • ️Fri Jan 01 2021

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

Yuko Makita et al. Nat Commun. 2021.

Erratum in

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.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1. Chimeric photoreceptor PpDUC1 and phylogeny of its host P. provasolii.

a Domain conservation between PpDUC1 and Arabidopsis CRY2 and PHYB. Domain structure of PpDUC1 constructed with PAS: Per-Arnt-Sim, GAF: cGMP-specific phosphodiesterases, adenylyl cyclases and FhlA. PHY: phytochrome, His: histidine kinase domain, PHR: photolyase-homologous region, and FAD: flavin adenine dinucleotide. b Light microscopic image of coccoid cells of P. provasolii NIES-2893. Scale bar = 5 µm. Observations were repeated more than three times and representative cells are shown. c Phylogeny of P. provasolii and genome statistics of the main lineages of Viridiplantae. Maximum likelihood (ML) tree of 105 orthologous proteins. The dataset was composed of 41,023 amino acids from 21 species that have genomes available, including P. provasolii. Bootstrap percentages (BPs) and Bayesian posterior probabilities (BPP) are shown above and below the lines, respectively. Bold lines show BP = 100 and BPP = 1.00.

Fig. 2
Fig. 2. Photoconversion of PpPHY and PpCRY.

a Domain structure of PpDUC. PpPHY (magenta) and PpCRY (cyan) regions are shown with their molecular sizes and amino acid positions. b Absorption spectra of the dark state (15Z–PCB, Po form) and the photoproduct state (15E–PCB, Pfr form) of PpPHY expressed in C41_pKT271 (harboring the PCB-synthetic system). The normalized difference spectrum (dark state—photoproduct state) was calculated from these absorption spectra. c Absorption spectra of the dark state (FADOX, Pb form) and the photoproduct state (FAD⋅–, Puv form) of PpCRY expressed in C41_pG-KJE8 (harboring the chaperone expression system). The normalized difference spectrum (dark state— photoproduct state) was calculated from these absorption spectra. The absorption maxima of PpPHY and PpCRY are reported in Supplementary Table 1. Assignment of chromophores incorporated in PpPHY and PpCRY was performed by comparison with each standard, which are reported in Supplementary Fig. 5.

Fig. 3
Fig. 3. Subcellular localization of PpDUC1 in tobacco leaves.

a Schematic diagrams of the domains in the PpPHY, PpCRY and PpDUC1 constructs used in the N. benthamiana leaf injection assay. b Immunoblot images of protein extract from N. benthamiana leaf tissue. Each protein was detected using an α-GFP antibody. Mock, non-injected leaf. Black arrows denote non-specific bands. Dot indicates the dye front. Experiments were repeated two times, and the results of one representative experiment are shown. c Leaf injection assay in N. benthamiana pavement cells transiently expressing PpPHY-GFP, PpCRY-GFP and PpDUC1-GFP with HY5-mCherry to indicate the nucleus. Observations were performed three times with similar results. DIC, differential interference contrast images; GFP, GFP fluorescence images; Merged, merged images of GFP and mCherry fluorescence images. Scale bar = 20 μm. The source data underlying Fig. 3b are provided as a Source Data file.

Fig. 4
Fig. 4. Evolutionary scenario of PHY and pCRY in chlorophytes.

The phylogenetic relationships of representative chlorophytes and the domain structures of their PHYs and pCRYs are shown. The tree topology is based on this study. The NCBI-nr database or MMETSP assemblies were searched for PHYs and pCRYs. Each domain is depicted by a different color.

Fig. 5
Fig. 5. Transcriptome analysis under monochromatic blue, orange, and far-red light.

a Number of DEGs under each monochromatic light (blue, orange, far-red) against dark conditions. Right: samples were treated with DCMU; left: no DCMU treatment. The DEG is defined as >1.5-fold for gene expression with a q-value < 0.05. b Venn-diagram of number of DEGs in Fig. 5a. c GO enrichment analysis for 686 co-regulated DEGs under blue and orange light. d Expression values for DUC1 and light-signaling genes. The source data underlying Fig. 5b, d are provided as a Source Data file.

Similar articles

Cited by

References

    1. Li FW, et al. Phytochrome diversity in green plants and the origin of canonical plant phytochromes. Nat. Commun. 2015;6:7852. - PMC - PubMed
    1. Rockwell NC, et al. Eukaryotic algal phytochromes span the visible spectrum. Proc. Natl Acad. Sci. USA. 2014;111:3871–3876. - PMC - PubMed
    1. Rockwell NC, Su YS, Lagarias JC. Phytochrome structure and signaling mechanisms. Annu. Rev. Plant Biol. 2006;57:837–858. - PMC - PubMed
    1. Lemieux C, Otis C, Turmel M. Six newly sequenced chloroplast genomes from prasinophyte green algae provide insights into the relationships among prasinophyte lineages and the diversity of streamlined genome architecture in picoplanktonic species. BMC Genomics. 2014;15:857. - PMC - PubMed
    1. Guillard RRL, Keller MD, O’Kelly CJ, Floyd GL. Pycnococcus provasolii gen. et sp. nov., a coccoid prasinoxanthin-containing phytoplankter from the Western North Atlantic and Gulf of Mexico. J. Phycol. 1991;27:39–47.

Publication types

MeSH terms

Substances