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Miyagishima SY. Taming the perils of photosynthesis by eukaryotes: constraints on endosymbiotic evolution in aquatic ecosystems. Commun Biol 2023; 6:1150. [PMID: 37952050 PMCID: PMC10640588 DOI: 10.1038/s42003-023-05544-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 11/03/2023] [Indexed: 11/14/2023] Open
Abstract
An ancestral eukaryote acquired photosynthesis by genetically integrating a cyanobacterial endosymbiont as the chloroplast. The chloroplast was then further integrated into many other eukaryotic lineages through secondary endosymbiotic events of unicellular eukaryotic algae. While photosynthesis enables autotrophy, it also generates reactive oxygen species that can cause oxidative stress. To mitigate the stress, photosynthetic eukaryotes employ various mechanisms, including regulating chloroplast light absorption and repairing or removing damaged chloroplasts by sensing light and photosynthetic status. Recent studies have shown that, besides algae and plants with innate chloroplasts, several lineages of numerous unicellular eukaryotes engage in acquired phototrophy by hosting algal endosymbionts or by transiently utilizing chloroplasts sequestrated from algal prey in aquatic ecosystems. In addition, it has become evident that unicellular organisms engaged in acquired phototrophy, as well as those that feed on algae, have also developed mechanisms to cope with photosynthetic oxidative stress. These mechanisms are limited but similar to those employed by algae and plants. Thus, there appear to be constraints on the evolution of those mechanisms, which likely began by incorporating photosynthetic cells before the establishment of chloroplasts by extending preexisting mechanisms to cope with oxidative stress originating from mitochondrial respiration and acquiring new mechanisms.
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Affiliation(s)
- Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan.
- The Graduate University for Advanced Studies, SOKENDAI, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan.
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Cooney EC, Holt CC, Jacko-Reynolds VKL, Leander BS, Keeling PJ. Photosystems in the eye-like organelles of heterotrophic warnowiid dinoflagellates. Curr Biol 2023; 33:4252-4260.e3. [PMID: 37703877 DOI: 10.1016/j.cub.2023.08.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/03/2023] [Accepted: 08/16/2023] [Indexed: 09/15/2023]
Abstract
Warnowiid dinoflagellates contain a highly complex camera-eye-like structure called the ocelloid that is composed of different organelles resembling parts of metazoan eyes, including a modified plastid that serves as the retinal body.1 The overall structure of the ocelloid has been investigated by microscopy; because warnowiids are not in culture and are rare in nature, we know little about their function.1,2 Here, we generate single-cell transcriptomes from 18 warnowiid cells collected directly from the marine environment representing all 4 known genera and 1 previously undescribed genus, as well as 8 cells from a related lineage, the polykrikoids. Phylogenomic analyses show that photosynthesis was independently lost twice in warnowiids. Interestingly, the non-photosynthetic taxa still express a variety of photosynthesis-related proteins. Nematodinium and Warnowia (known or suspected to be photosynthetic1,3) unsurprisingly express a full complement of photosynthetic pathway components. However, non-photosynthetic genera with ocelloids were also found to express light-harvesting complexes, photosystem I, photosynthetic electron transport (PET), cytochrome b6f, and, in Erythropsidinium, plastid ATPase, representing all major complexes except photosystem II and the Calvin cycle. This suggests that the non-photosynthetic retinal body has retained a reduced but still substantial photosynthetic apparatus that perhaps functions using cyclic electron flow (CEF). This may support ATP synthesis in a reduced capacity, but it is also possible that the photosystem has been co-opted to function as a light-driven proton pump at the heart of the sensory mechanism within the complex architecture of ocelloids.
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Affiliation(s)
- Elizabeth C Cooney
- Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Hakai Institute, Heriot Bay, BC V9W 5E3, Canada.
| | - Corey C Holt
- Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Hakai Institute, Heriot Bay, BC V9W 5E3, Canada
| | | | - Brian S Leander
- Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Patrick J Keeling
- Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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Onuma R, Hirooka S, Kanesaki Y, Fujiwara T, Yoshikawa H, Miyagishima SY. Changes in the transcriptome, ploidy, and optimal light intensity of a cryptomonad upon integration into a kleptoplastic dinoflagellate. THE ISME JOURNAL 2020; 14:2407-2423. [PMID: 32514116 PMCID: PMC7490267 DOI: 10.1038/s41396-020-0693-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/19/2020] [Accepted: 05/27/2020] [Indexed: 11/30/2022]
Abstract
Endosymbiosis of unicellular eukaryotic algae into previously nonphotosynthetic eukaryotes has established chloroplasts in several eukaryotic lineages. In addition, certain unicellular organisms in several different lineages ingest algae and utilize them as temporal chloroplasts (kleptoplasts) for weeks to months before digesting them. Among these organisms, the dinoflagellate Nusuttodinium aeruginosum ingests the cryptomonad Chroomonas sp. and enlarges the kleptoplast with the aid of the cryptomonad nucleus. To understand how the cryptomonad nucleus is remodeled in the dinoflagellate, here we examined changes in the transcriptome and ploidy of the ingested nucleus. We show that, after ingestion, genes involved in metabolism, translation, and DNA replication are upregulated while those involved in sensory systems and cell motility are downregulated. In the dinoflagellate cell, the cryptomonad nucleus undergoes polyploidization that correlates with an increase in the mRNA levels of upregulated genes. In addition, the ingested nucleus almost loses transcriptional responses to light. Because polyploidization and loss of transcriptional regulation are also known to have occurred during the establishment of endosymbiotic organelles, these changes are probably a common trend in endosymbiotic evolution. Furthermore, we show that the kleptoplast and dinoflagellate are more susceptible to high light than the free-living cryptomonad but that the ingested nucleus reduces this damage.
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Affiliation(s)
- Ryo Onuma
- Department of Gene Function and Phenomics, National Institute of Genetics, Yata 1111, Mishima, Shizuoka, 411-8540, Japan.
| | - Shunsuke Hirooka
- Department of Gene Function and Phenomics, National Institute of Genetics, Yata 1111, Mishima, Shizuoka, 411-8540, Japan
| | - Yu Kanesaki
- Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya, Suruga, Shizuoka, 422-8529, Japan
| | - Takayuki Fujiwara
- Department of Gene Function and Phenomics, National Institute of Genetics, Yata 1111, Mishima, Shizuoka, 411-8540, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Yata 1111, Mishima, Shizuoka, 411-8540, Japan
| | - Hirofumi Yoshikawa
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo, 156-8502, Japan
| | - Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, Yata 1111, Mishima, Shizuoka, 411-8540, Japan.
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Yata 1111, Mishima, Shizuoka, 411-8540, Japan.
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A kleptoplastidic dinoflagellate and the tipping point between transient and fully integrated plastid endosymbiosis. Proc Natl Acad Sci U S A 2019; 116:17934-17942. [PMID: 31427512 DOI: 10.1073/pnas.1910121116] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Plastid endosymbiosis has been a major force in the evolution of eukaryotic cellular complexity, but how endosymbionts are integrated is still poorly understood at a mechanistic level. Dinoflagellates, an ecologically important protist lineage, represent a unique model to study this process because dinoflagellate plastids have repeatedly been reduced, lost, and replaced by new plastids, leading to a spectrum of ages and integration levels. Here we describe deep-transcriptomic analyses of the Antarctic Ross Sea dinoflagellate (RSD), which harbors long-term but temporary kleptoplasts stolen from haptophyte prey, and is closely related to dinoflagellates with fully integrated plastids derived from different haptophytes. In some members of this lineage, called the Kareniaceae, their tertiary haptophyte plastids have crossed a tipping point to stable integration, but RSD has not, and may therefore reveal the order of events leading up to endosymbiotic integration. We show that RSD has retained its ancestral secondary plastid and has partitioned functions between this plastid and the kleptoplast. It has also obtained genes for kleptoplast-targeted proteins via horizontal gene transfer (HGT) that are not derived from the kleptoplast lineage. Importantly, many of these HGTs are also found in the related species with fully integrated plastids, which provides direct evidence that genetic integration preceded organelle fixation. Finally, we find that expression of kleptoplast-targeted genes is unaffected by environmental parameters, unlike prey-encoded homologs, suggesting that kleptoplast-targeted HGTs have adapted to posttranscriptional regulation mechanisms of the host.
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Stamatakis K, Broussos PI, Panagiotopoulou A, Gast RJ, Pelecanou M, Papageorgiou GC. Light-adaptive state transitions in the Ross Sea haptophyte Phaeocystis antarctica and in dinoflagellate cells hosting kleptoplasts derived from it. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1860:102-110. [PMID: 30414926 DOI: 10.1016/j.bbabio.2018.11.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 09/11/2018] [Accepted: 11/07/2018] [Indexed: 11/19/2022]
Abstract
Light state transitions (STs) is a reversible physiological process that oxygenic photosynthetic organisms use in order to minimize imbalances in the electronic excitation delivery to the reaction centers of Photosystems I and II, and thus to optimize photosynthesis. STs have been studied extensively in plants, green algae, red algae and cyanobacteria, but sparsely in algae with secondary red algal plastids, such as diatoms and haptophytes, despite their immense ecological significance. In the present work, we examine whether the haptophyte alga Phaeocystis antarctica, and dinoflagellate cells that host kleptoplasts derived from P. antarctica, both endemic in the Ross Sea, Antarctica, are capable of light adaptive STs. In these organisms, Chl a fluorescence can be excited either by direct light absorption, or indirectly by electronic excitation (EE) transfer from ultraviolet light absorbing mycosporine-like amino acids (MAAs) to Chl a (Stamatakis et al., Biochim. Biophys. Acta 1858 [2017] 189-195). Here we show that, on adaptation to PS II-selective light, dark-adapted P. antarctica cells shift from light state 1 (ST1; more EE ending up in PS II) to light state 2 (ST2; more EE ending up in PS I), as revealed by the spectral distribution of directly-excited Chl a fluorescence and by changes in the macro-organization of pigment-protein complexes evidenced by circular dichroism (CD) spectroscopy. In contrast, no STs are clearly detected in the case of the kleptoplast-hosting dinoflagellate cells, and in the case of indirectly excited Chls a, via MAAs, in P. antarctica cells.
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Affiliation(s)
- Kostas Stamatakis
- Institute of Biosciences and Applications, NCSR "Demokritos", 15310, Aghia Paraskevi Attikis, Greece.
| | - Panayiotis-Ilias Broussos
- Institute of Biosciences and Applications, NCSR "Demokritos", 15310, Aghia Paraskevi Attikis, Greece
| | - Angeliki Panagiotopoulou
- Institute of Biosciences and Applications, NCSR "Demokritos", 15310, Aghia Paraskevi Attikis, Greece
| | - Rebecca J Gast
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Maria Pelecanou
- Institute of Biosciences and Applications, NCSR "Demokritos", 15310, Aghia Paraskevi Attikis, Greece
| | - George C Papageorgiou
- Institute of Biosciences and Applications, NCSR "Demokritos", 15310, Aghia Paraskevi Attikis, Greece
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Orallo DE, Fangio MF, Poblet M, Carignan MO, Bernal L, Carreto JI, Bertolotti SG, Churio MS. Photochemistry and Photophysics of Shinorine Dimethyl Ester. Photochem Photobiol 2018; 94:829-833. [PMID: 29315606 DOI: 10.1111/php.12884] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 12/05/2017] [Indexed: 01/25/2023]
Abstract
The photostability and photophysical properties of the dimethyl ester of the mycosporine-like amino acid shinorine have been experimentally evaluated in aqueous solution and in the presence of direct micelles prepared with a cationic or an anionic detergent, respectively. In comparison with shinorine, the ester molecule increases the photostability, the fluorescence quantum yield and the fluorescence lifetime in water as well as in the micellar solutions. The effects are more pronounced in sodium dodecyl sulfate solutions and suggest that the electrostatic attractions with the micellar interface contribute to limit the movement of the molecules and influence the relative rate of their deactivation channels. However, the predominance of the nonradiative decay is maintained together with the UV photoprotective ability of this atypical mycosporine species.
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Affiliation(s)
- Dalila E Orallo
- Departamento de Química, Facultad de Ciencias Exactas y Naturales, Instituto de Investigaciones Físicas de Mar del Plata (CONICET-UNMDP), Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
| | - María Florencia Fangio
- Departamento de Química, Facultad de Ciencias Exactas y Naturales, Instituto de Investigaciones Físicas de Mar del Plata (CONICET-UNMDP), Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
| | - Martin Poblet
- Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
| | - Mario O Carignan
- Instituto Nacional de Investigación y Desarrollo Pesquero, Mar del Plata, Argentina
| | - Luis Bernal
- Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
| | - José I Carreto
- Instituto Nacional de Investigación y Desarrollo Pesquero, Mar del Plata, Argentina
| | - Sonia G Bertolotti
- Departamento de Química, Universidad Nacional de Río Cuarto, CONICET, Río Cuarto, Argentina
| | - María Sandra Churio
- Departamento de Química, Facultad de Ciencias Exactas y Naturales, Instituto de Investigaciones Físicas de Mar del Plata (CONICET-UNMDP), Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
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Osborn AR, Kean KM, Karplus PA, Mahmud T. The sedoheptulose 7-phosphate cyclases and their emerging roles in biology and ecology. Nat Prod Rep 2017; 34:945-956. [PMID: 28497152 DOI: 10.1039/c7np00017k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering up to: 1999-2016This highlight covers a family of enzymes of growing importance, the sedoheptulose 7-phosphate cyclases, initially of interest due to their involvement in the biosynthesis of pharmaceutically relevant secondary metabolites. More recently, these enzymes have been found throughout Prokarya and Eukarya, suggesting their broad potential biological roles in nature.
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Affiliation(s)
- Andrew R Osborn
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331-3507, USA.
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