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Santin A, Collura F, Singh G, Morlino MS, Bizzotto E, Bellan A, Gupte AP, Favaro L, Campanaro S, Treu L, Morosinotto T. Deciphering the genetic landscape of enhanced poly-3-hydroxybutyrate production in Synechocystis sp. B12. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:101. [PMID: 39014484 PMCID: PMC11253406 DOI: 10.1186/s13068-024-02548-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 07/03/2024] [Indexed: 07/18/2024]
Abstract
BACKGROUND Microbial biopolymers such as poly-3-hydroxybutyrate (PHB) are emerging as promising alternatives for sustainable production of biodegradable bioplastics. Their promise is heightened by the potential utilisation of photosynthetic organisms, thus exploiting sunlight and carbon dioxide as source of energy and carbon, respectively. The cyanobacterium Synechocystis sp. B12 is an attractive candidate for its superior ability to accumulate high amounts of PHB as well as for its high-light tolerance, which makes it extremely suitable for large-scale cultivation. Beyond its practical applications, B12 serves as an intriguing model for unravelling the molecular mechanisms behind PHB accumulation. RESULTS Through a multifaceted approach, integrating physiological, genomic and transcriptomic analyses, this work identified genes involved in the upregulation of chlorophyll biosynthesis and phycobilisome degradation as the possible candidates providing Synechocystis sp. B12 an advantage in growth under high-light conditions. Gene expression differences in pentose phosphate pathway and acetyl-CoA metabolism were instead recognised as mainly responsible for the increased Synechocystis sp. B12 PHB production during nitrogen starvation. In both response to strong illumination and PHB accumulation, Synechocystis sp. B12 showed a metabolic modulation similar but more pronounced than the reference strain, yielding in better performances. CONCLUSIONS Our findings shed light on the molecular mechanisms of PHB biosynthesis, providing valuable insights for optimising the use of Synechocystis in economically viable and sustainable PHB production. In addition, this work supplies crucial knowledge about the metabolic processes involved in production and accumulation of these molecules, which can be seminal for the application to other microorganisms as well.
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Grants
- 691712 Horizon 2020 Framework Programme
- 691712 Horizon 2020 Framework Programme
- 691712 Horizon 2020 Framework Programme
- 691712 Horizon 2020 Framework Programme
- 691712 Horizon 2020 Framework Programme
- 691712 Horizon 2020 Framework Programme
- 691712 Horizon 2020 Framework Programme
- 691712 Horizon 2020 Framework Programme
- 327331 Ministero dell'Istruzione, dell'Università e della Ricerca
- 327331 Ministero dell'Istruzione, dell'Università e della Ricerca
- 327331 Ministero dell'Istruzione, dell'Università e della Ricerca
- 327331 Ministero dell'Istruzione, dell'Università e della Ricerca
- 327331 Ministero dell'Istruzione, dell'Università e della Ricerca
- 327331 Ministero dell'Istruzione, dell'Università e della Ricerca
- 327331 Ministero dell'Istruzione, dell'Università e della Ricerca
- 327331 Ministero dell'Istruzione, dell'Università e della Ricerca
- 327331 Ministero dell'Istruzione, dell'Università e della Ricerca
- Ministero dell’Istruzione, dell’Università e della Ricerca
- Università degli Studi di Padova
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Affiliation(s)
- Anna Santin
- Department of Biology, University of Padova, 35131, Padua, Italy.
| | - Flavio Collura
- Department of Biology, University of Padova, 35131, Padua, Italy
| | - Garima Singh
- Department of Biology, University of Padova, 35131, Padua, Italy
| | | | - Edoardo Bizzotto
- Department of Biology, University of Padova, 35131, Padua, Italy
| | | | - Ameya Pankaj Gupte
- Waste to Bioproducts Lab, Department of Agronomy Food Natural Resources Animals and Environment, University of Padova - Agripolis, 35020, Legnaro, PD, Italy
| | - Lorenzo Favaro
- Waste to Bioproducts Lab, Department of Agronomy Food Natural Resources Animals and Environment, University of Padova - Agripolis, 35020, Legnaro, PD, Italy
- Department of Microbiology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | | | - Laura Treu
- Department of Biology, University of Padova, 35131, Padua, Italy
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Espinoza-Corral R, Iwai M, Zavřel T, Lechno-Yossef S, Sutter M, Červený J, Niyogi KK, Kerfeld CA. Phycobilisome protein ApcG interacts with PSII and regulates energy transfer in Synechocystis. PLANT PHYSIOLOGY 2024; 194:1383-1396. [PMID: 37972281 PMCID: PMC10904348 DOI: 10.1093/plphys/kiad615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/25/2023] [Accepted: 10/25/2023] [Indexed: 11/19/2023]
Abstract
Photosynthetic organisms harvest light using pigment-protein complexes. In cyanobacteria, these are water-soluble antennae known as phycobilisomes (PBSs). The light absorbed by PBS is transferred to the photosystems in the thylakoid membrane to drive photosynthesis. The energy transfer between these complexes implies that protein-protein interactions allow the association of PBS with the photosystems. However, the specific proteins involved in the interaction of PBS with the photosystems are not fully characterized. Here, we show in Synechocystis sp. PCC 6803 that the recently discovered PBS linker protein ApcG (sll1873) interacts specifically with PSII through its N-terminal region. Growth of cyanobacteria is impaired in apcG deletion strains under light-limiting conditions. Furthermore, complementation of these strains using a phospho-mimicking version of ApcG causes reduced growth under normal growth conditions. Interestingly, the interaction of ApcG with PSII is affected when a phospho-mimicking version of ApcG is used, targeting the positively charged residues interacting with the thylakoid membrane, suggesting a regulatory role mediated by phosphorylation of ApcG. Low-temperature fluorescence measurements showed decreased PSI fluorescence in apcG deletion and complementation strains. The PSI fluorescence was the lowest in the phospho-mimicking complementation strain, while the pull-down experiment showed no interaction of ApcG with PSI under any tested condition. Our results highlight the importance of ApcG for selectively directing energy harvested by the PBS and imply that the phosphorylation status of ApcG plays a role in regulating energy transfer from PSII to PSI.
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Affiliation(s)
- Roberto Espinoza-Corral
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Masakazu Iwai
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Tomáš Zavřel
- Department of Adaptive Biotechnologies, Global Change Research Institute of the Czech Academy of Sciences, Drásov 470, CZ-66424 Drásov, Czech Republic
| | - Sigal Lechno-Yossef
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Markus Sutter
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jan Červený
- Department of Adaptive Biotechnologies, Global Change Research Institute of the Czech Academy of Sciences, Drásov 470, CZ-66424 Drásov, Czech Republic
| | - Krishna K Niyogi
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA
| | - Cheryl A Kerfeld
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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Yan F, Li M, Zang S, Xu Z, Bao M, Wu H. UV radiation and temperature increase alter the PSII function and defense mechanisms in a bloom-forming cyanobacterium Microcystis aeruginosa. Front Microbiol 2024; 15:1351796. [PMID: 38292251 PMCID: PMC10825000 DOI: 10.3389/fmicb.2024.1351796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/04/2024] [Indexed: 02/01/2024] Open
Abstract
The aim was to determine the response of a bloom-forming Microcystis aeruginosa to climatic changes. Cultures of M. aeruginosa FACHB 905 were grown at two temperatures (25°C, 30°C) and exposed to high photosynthetically active radiation (PAR: 400-700 nm) alone or combined with UVR (PAR + UVR: 295-700 nm) for specified times. It was found that increased temperature enhanced M. aeruginosa sensitivity to both PAR and PAR + UVR as shown by reduced PSII quantum yields (Fv/Fm) in comparison with that at growth temperature (25°C), the presence of UVR significantly exacerbated the photoinhibition. M. aeruginosa cells grown at high temperature exhibited lower PSII repair rate (Krec) and sustained nonphotochemical quenching (NPQs) induction during the radiation exposure, particularly for PAR + UVR. Although high temperature alone or worked with UVR induced higher SOD and CAT activity and promoted the removal rate of PsbA, it seemed not enough to prevent the damage effect from them showing by the increased value of photoinactivation rate constant (Kpi). In addition, the energetic cost of microcystin synthesis at high temperature probably led to reduced materials and energy available for PsbA turnover, thus may partly account for the lower Krec and the declination of photosynthetic activity in cells following PAR and PAR + UVR exposure. Our findings suggest that increased temperature modulates the sensitivity of M. aeruginosa to UVR by affecting the PSII repair and defense capacity, thus influencing competitiveness and abundance in the future water environment.
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Affiliation(s)
- Fang Yan
- School of Life Science, Ludong University, Yantai, China
- Key Laboratory of Marine Biotechnology in Universities of Shandong, Ludong University, Yantai, China
| | - Mingze Li
- School of Life Science, Ludong University, Yantai, China
- Key Laboratory of Marine Biotechnology in Universities of Shandong, Ludong University, Yantai, China
| | - Shasha Zang
- School of Life Science, Ludong University, Yantai, China
- Key Laboratory of Marine Biotechnology in Universities of Shandong, Ludong University, Yantai, China
| | - Zhiguang Xu
- School of Life Science, Ludong University, Yantai, China
- Key Laboratory of Marine Biotechnology in Universities of Shandong, Ludong University, Yantai, China
| | - Menglin Bao
- School of Life Science, Ludong University, Yantai, China
- Key Laboratory of Marine Biotechnology in Universities of Shandong, Ludong University, Yantai, China
| | - Hongyan Wu
- School of Life Science, Ludong University, Yantai, China
- Key Laboratory of Marine Biotechnology in Universities of Shandong, Ludong University, Yantai, China
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Park Y, Kim W, Kim M, Park W. The β-Lactamase Activity at the Community Level Confers β-Lactam Resistance to Bloom-Forming Microcystis aeruginosa Cells. J Microbiol 2023; 61:807-820. [PMID: 37851310 DOI: 10.1007/s12275-023-00082-0] [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: 08/28/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 10/19/2023]
Abstract
Many freshwater cyanobacteria, including Microcystis aeruginosa, lack several known antibiotic resistance genes; however, both axenic and xenic M. aeruginosa strains exhibited high antibiotic resistance against many antibiotics under our tested concentrations, including colistin, trimethoprim, and kanamycin. Interestingly, axenic PCC7806, although not the xenic NIBR18 and NIBR452 strains, displayed susceptibility to ampicillin and amoxicillin, indicating that the associated bacteria in the phycosphere could confer such antibiotic resistance to xenic strains. Fluorescence and scanning electron microscopic observations revealed their tight association, leading to possible community-level β-lactamase activity. Combinatory treatment of ampicillin with a β-lactamase inhibitor, sulbactam, abolished the ampicillin resistance in the xenic stains. The nitrocefin-based assay confirmed the presence of significant community-level β-lactamase activity. Our tested low ampicillin concentration and high β-lactamase activity could potentially balance the competitive advantage of these dominant species and provide opportunities for the less competitive species, thereby resulting in higher bacterial diversity under ampicillin treatment conditions. Non-PCR-based metagenome data from xenic NIBR18 cultures revealed the dominance of blaOXA-related antibiotic resistance genes followed by other class A β-lactamase genes (AST-1 and FAR-1). Alleviation of ampicillin toxicity could be observed only in axenic PCC7806, which had been cocultured with β-lactamase from other freshwater bacteria. Our study suggested M. aeruginosa develops resistance to old-class β-lactam antibiotics through altruism, where associated bacteria protect axenic M. aeruginosa cells.
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Affiliation(s)
- Yerim Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Wonjae Kim
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Minkyung Kim
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Woojun Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
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Whitman BT, Wang Y, Murray CRA, Glover MJN, Owttrim GW. Liquid-Liquid Phase Separation of the DEAD-Box Cyanobacterial RNA Helicase Redox (CrhR) into Dynamic Membraneless Organelles in Synechocystis sp. Strain PCC 6803. Appl Environ Microbiol 2023; 89:e0001523. [PMID: 36920190 PMCID: PMC10132119 DOI: 10.1128/aem.00015-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 02/17/2023] [Indexed: 03/16/2023] Open
Abstract
Compartmentalization of macromolecules into discrete non-lipid-bound bodies by liquid-liquid phase separation (LLPS) is a well-characterized regulatory mechanism frequently associated with the cellular stress response in eukaryotes. In contrast, the formation and importance of similar complexes is just becoming evident in bacteria. Here, we identify LLPS as the mechanism by which the DEAD-box RNA helicase, cyanobacterial RNA helicase redox (CrhR), compartmentalizes into dynamic membraneless organelles in a temporal and spatial manner in response to abiotic stress in the cyanobacterium Synechocystis sp. strain PCC 6803. Stress conditions induced CrhR to form a single crescent localized exterior to the thylakoid membrane, indicating that this region is a crucial domain in the cyanobacterial stress response. These crescents rapidly dissipate upon alleviation of the stress conditions. Furthermore, CrhR aggregation was mediated by LLPS in an RNA-dependent reaction. We propose that dynamic CrhR condensation performs crucial roles in RNA metabolism, enabling rapid adaptation of the photosynthetic apparatus to environmental stresses. These results expand our understanding of the role that functional compartmentalization of RNA helicases and thus RNA processing in membraneless organelles by LLPS-mediated protein condensation performs in the bacterial response to environmental stress. IMPORTANCE Oxygen-evolving photosynthetic cyanobacteria evolved ~3 billion years ago, performing fundamental roles in the biogeochemical evolution of the early Earth and continue to perform fundamental roles in nutrient cycling and primary productivity today. The phylum consists of diverse species that flourish in heterogeneous environments. A prime driver for survival is the ability to alter photosynthetic performance in response to the shifting environmental conditions these organisms continuously encounter. This study demonstrated that diverse abiotic stresses elicit dramatic changes in localization and structural organization of the RNA helicase CrhR associated with the photosynthetic thylakoid membrane. These dynamic changes, mediated by a liquid-liquid phase separation (LLPS)-mediated mechanism, reveal a novel mechanism by which cyanobacteria can compartmentalize the activity of ribonucleoprotein complexes in membraneless organelles. The results have significant consequences for understanding bacterial adaptation and survival in response to changing environmental conditions.
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Affiliation(s)
- Brendan T. Whitman
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Yixiong Wang
- Department of Oncology, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Cameron R. A. Murray
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Mark J. N. Glover
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - George W. Owttrim
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
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