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Huang C, Duan X, Ge H, Xiao Z, Zheng L, Wang G, Dong J, Wang Y, Zhang Y, Huang X, An H, Xu W, Wang Y. Parallel Proteomic Comparison of Mutants With Altered Carbon Metabolism Reveals Hik8 Regulation of P II Phosphorylation and Glycogen Accumulation in a Cyanobacterium. Mol Cell Proteomics 2023; 22:100582. [PMID: 37225018 PMCID: PMC10315926 DOI: 10.1016/j.mcpro.2023.100582] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 05/26/2023] Open
Abstract
Carbon metabolism is central to photosynthetic organisms and involves the coordinated operation and regulation of numerous proteins. In cyanobacteria, proteins involved in carbon metabolism are regulated by multiple regulators including the RNA polymerase sigma factor SigE, the histidine kinases Hik8, Hik31 and its plasmid-borne paralog Slr6041, and the response regulator Rre37. To understand the specificity and the cross-talk of such regulations, we simultaneously and quantitatively compared the proteomes of the gene knockout mutants for the regulators. A number of proteins showing differential expression in one or more mutants were identified, including four proteins that are unanimously upregulated or downregulated in all five mutants. These represent the important nodes of the intricate and elegant regulatory network for carbon metabolism. Moreover, serine phosphorylation of PII, a key signaling protein sensing and regulating in vivo carbon/nitrogen (C/N) homeostasis through reversible phosphorylation, is massively increased with a concomitant significant decrease in glycogen content only in the hik8-knockout mutant, which also displays impaired dark viability. An unphosphorylatable PII S49A substitution restored the glycogen content and rescued the dark viability of the mutant. Together, our study not only establishes the quantitative relationship between the targets and the corresponding regulators and elucidated their specificity and cross-talk but also unveils that Hik8 regulates glycogen accumulation through negative regulation of PII phosphorylation, providing the first line of evidence that links the two-component system with PII-mediated signal transduction and implicates them in the regulation of carbon metabolism.
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Affiliation(s)
- Chengcheng Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoxiao Duan
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Haitao Ge
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Zhen Xiao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Limin Zheng
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Gaojie Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Jinghui Dong
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yan Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yuanya Zhang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Xiahe Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Hongyu An
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Wu Xu
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, Louisiana, USA
| | - Yingchun Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
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He X, Liu H, Long L, Dong J, Huang S. Acclimation and stress response of Prochlorococcus to low salinity. Front Microbiol 2022; 13:1038136. [PMID: 36312958 PMCID: PMC9606707 DOI: 10.3389/fmicb.2022.1038136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 09/27/2022] [Indexed: 12/02/2022] Open
Abstract
Prochlorococcus is an obligate marine microorganism and the dominant autotroph in tropical and subtropical open ocean. However, the salinity range for growing and response to low salinity exposure of Prochlorococcus are still unknown. In this study, we found that low-light adapted Prochlorococcus stain NATL1A and high-light adapted strain MED4 could be acclimated in the lowest salinity of 25 and 28 psu, respectively. Analysis of the effective quantum yield of PSII photochemistry (Fv/Fm) indicated that both strains were stressed when growing in salinity lower than 34 psu. We then compared the global transcriptome of low salinity (28 psu) acclimated cells and cells growing in normal seawater salinity (34 psu). The transcriptomic responses of NATL1A and MED4 were approximately different, with more differentially expressed genes in NATL1A (525 genes) than in MED4 (277 genes). To cope with low salinity, NATL1A down-regulated the transcript of genes involved in translation, ribosomal structure and biogenesis and ATP-production, and up-regulated photosynthesis-related genes, while MED4 regulated these genes in an opposite way. In addition, both strains up-regulated an iron ABC transporter gene, idiA, suggesting low salinity acclimated cells could be iron limited. This study demonstrated the growing salinity range of Prochlorococcus cells and their global gene expression changes due to low salinity stress.
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Affiliation(s)
- Xiayu He
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Huairou, Beijing, China
| | - Huan Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Huairou, Beijing, China
| | - Lijuan Long
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Junde Dong
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Sijun Huang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
- *Correspondence: Sijun Huang,
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Klähn S, Mikkat S, Riediger M, Georg J, Hess WR, Hagemann M. Integrative analysis of the salt stress response in cyanobacteria. Biol Direct 2021; 16:26. [PMID: 34906211 PMCID: PMC8670252 DOI: 10.1186/s13062-021-00316-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 11/29/2021] [Indexed: 12/24/2022] Open
Abstract
Microorganisms evolved specific acclimation strategies to thrive in environments of high or fluctuating salinities. Here, salt acclimation in the model cyanobacterium Synechocystis sp. PCC 6803 was analyzed by integrating transcriptomic, proteomic and metabolomic data. A dynamic reorganization of the transcriptome occurred during the first hours after salt shock, e.g. involving the upregulation of genes to activate compatible solute biochemistry balancing osmotic pressure. The massive accumulation of glucosylglycerol then had a measurable impact on the overall carbon and nitrogen metabolism. In addition, we observed the coordinated induction of putative regulatory RNAs and of several proteins known for their involvement in other stress responses. Overall, salt-induced changes in the proteome and transcriptome showed good correlations, especially among the stably up-regulated proteins and their transcripts. We define an extended salt stimulon comprising proteins directly or indirectly related to compatible solute metabolism, ion and water movements, and a distinct set of regulatory RNAs involved in post-transcriptional regulation. Our comprehensive data set provides the basis for engineering cyanobacterial salt tolerance and to further understand its regulation.
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Affiliation(s)
- Stephan Klähn
- Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Leipzig, Germany
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Stefan Mikkat
- Core Facility Proteome Analysis, Rostock University Medical Center, Rostock, Germany
| | - Matthias Riediger
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Jens Georg
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Wolfgang R. Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, A.-Einstein-Str. 3, 18059 Rostock, Germany
- Department Life, Light and Matter, University of Rostock, Rostock, Germany
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Oeser S, Wallner T, Schuergers N, Bučinská L, Sivabalasarma S, Bähre H, Albers SV, Wilde A. Minor pilins are involved in motility and natural competence in the cyanobacterium Synechocystis sp. PCC 6803. Mol Microbiol 2021; 116:743-765. [PMID: 34115422 DOI: 10.1111/mmi.14768] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 06/04/2021] [Accepted: 06/05/2021] [Indexed: 11/28/2022]
Abstract
Cyanobacteria synthesize type IV pili, which are known to be essential for motility, adhesion and natural competence. They consist of long flexible fibers that are primarily composed of the major pilin PilA1 in Synechocystis sp. PCC 6803. In addition, Synechocystis encodes less abundant pilin-like proteins, which are known as minor pilins. In this study, we show that the minor pilin PilA5 is essential for natural transformation but is dispensable for motility and flocculation. In contrast, a set of minor pilins encoded by the pilA9-slr2019 transcriptional unit are necessary for motility but are dispensable for natural transformation. Neither pilA5-pilA6 nor pilA9-slr2019 are essential for pilus assembly as mutant strains showed type IV pili on the cell surface. Three further gene products with similarity to PilX-like minor pilins have a function in flocculation of Synechocystis. The results of our study indicate that different minor pilins facilitate distinct pilus functions. Further, our microarray analysis demonstrated that the transcription levels of the minor pilin genes change in response to surface contact. A total of 122 genes were determined to have altered transcription between planktonic and surface growth, including several plasmid genes which are involved exopolysaccharide synthesis and the formation of bloom-like aggregates.
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Affiliation(s)
- Sabrina Oeser
- Molecular Genetics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Thomas Wallner
- Molecular Genetics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Nils Schuergers
- Molecular Genetics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Lenka Bučinská
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Trebon, Czech Republic
| | - Shamphavi Sivabalasarma
- Molecular Biology of Archaea, Institute of Biology II, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Heike Bähre
- Research Core Unit Metabolomics, Medical School Hannover, Hannover, Germany
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology II, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Annegret Wilde
- Molecular Genetics, Institute of Biology III, University of Freiburg, Freiburg, Germany
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5
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New insights into the function of the proteins IsiC and IsiD from Synechocystis sp. PCC 6803 under iron limitation. Appl Microbiol Biotechnol 2021; 105:4693-4707. [PMID: 34019114 DOI: 10.1007/s00253-021-11347-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 04/30/2021] [Accepted: 05/09/2021] [Indexed: 10/25/2022]
Abstract
Iron is a common cofactor in biological processes such as respiration, photosynthesis, and nitrogen fixation. The genes isiC and isiD encode unknown proteins, and the growth of ΔisiC and ΔisiD mutants is inhibited under iron-deficient conditions. To study the regulatory mechanisms of IsiC and IsiD during iron starvation, we carried out transcriptome and metabolome sequencing. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the photosynthesis, nitrogen metabolism, and ABC transporter pathways play a vital role in regulating iron deficiency. Upon iron repletion, IsiC and IsiD also have a regulatory effect on these pathways. Additionally, KEGG analysis of the differential metabolites of wild type (WT) and mutants showed that they were all enriched in starch and sucrose metabolism after iron limitation. Weighted gene co-expression network analysis (WGCNA) constructed a co-expression network of differentially expressed genes with phenotypes and metabolites, and finally identified five modules. The turquoise module was positively correlated with iron deficiency. In contrast, the WT and blue module exhibited a negative correlation, and the mutants ΔisiC and ΔisiD were positively correlated with the gray and brown modules, respectively. WGCNA also analyzed the relationship between metabolites and phenotypes, and the green module was related to iron starvation. The co-expression network determined the hub genes and metabolites of each module. This study lays a foundation for a better understanding of cyanobacteria in response to iron deficiency. KEY POINTS: • Nitrogen metabolism and ABC transporters are involved in iron regulation. • Starch and sucrose metabolism is related to the regulation of iron deficiency. • WGCNA analyzes the correlation between genes and metabolites.
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6
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Takashima K, Nagao S, Kizawa A, Suzuki T, Dohmae N, Hihara Y. The role of transcriptional repressor activity of LexA in salt-stress responses of the cyanobacterium Synechocystis sp. PCC 6803. Sci Rep 2020; 10:17393. [PMID: 33060671 PMCID: PMC7567884 DOI: 10.1038/s41598-020-74534-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 10/05/2020] [Indexed: 12/24/2022] Open
Abstract
Different from typical LexA repressors in heterotrophic bacteria exerting SOS response by auto-cleavage, cyanobacterial LexAs, especially that of Synechocystis sp. PCC 6803 (S.6803), have been suggested be involved in regulation of a number of genes related to various cellular processes, rather than the typical SOS regulon. When and how cyanobacterial LexAs are triggered to regulate its target genes have remained unknown. In this study, we found the profound repressing effect of LexA on salt-stress inducible genes in S.6803. The repressing activity of LexA was likely to persist during salt stress and the salt response of these genes was mainly achieved by other regulators than LexA, suggesting that the physiological role of LexA is fine-tuning of gene expression in response to environmental changes. Although the amount and oligomeric state of LexA were unchanged upon salt stress, two-dimensional electrophoresis and liquid chromatography-tandem mass spectrometry analyses detected a change in posttranslational modification in a small fraction of LexA molecules, possibly dephosphorylation of Ser173, after 30 min upon the upshift in salt concentration. Activity of LexA in S.6803 may be under gradual control by posttranslational modification to fine-tune gene expression, which is contrasted with the digital switching-off regulation by auto-cleavage in heterotrophic bacteria.
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Affiliation(s)
- Kosuke Takashima
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama, 338-8570, Japan
| | - Syota Nagao
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama, 338-8570, Japan
| | - Ayumi Kizawa
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama, 338-8570, Japan.,Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Takehiro Suzuki
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Yukako Hihara
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama, 338-8570, Japan.
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7
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Grattieri M, Beaver K, Gaffney EM, Dong F, Minteer SD. Advancing the fundamental understanding and practical applications of photo-bioelectrocatalysis. Chem Commun (Camb) 2020; 56:8553-8568. [PMID: 32578607 DOI: 10.1039/d0cc02672g] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Photo-bioelectrocatalysis combines the natural and highly sophisticated process of photosynthesis in biological entities with an abiotic electrode surface, to perform semi-artificial photosynthesis. However, challenges must be overcome, from the establishment and understanding of the photoexcited electron harvesting process at the electrode to the electrochemical characterization of these biotic/abiotic systems, and their subsequent tuning for enhancing energy generation (chemical and/or electrical). This Feature Article discusses the various approaches utilized to tackle these challenges, particularly focusing on powerful multi-disciplinary approaches for understanding and improving photo-bioelectrocatalysis. Among them is the combination of experimental evidence and quantum mechanical calculations, the use of bioinformatics to understand photo-bioelectrocatalysis at a metabolic level, or bioengineering to improve and facilitate photo-bioelectrocatalysis. Key aspects for the future development of photo-bioelectrocatalysis are presented alongside future research needs and promising applications of semi-artificial photosynthesis.
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Affiliation(s)
- Matteo Grattieri
- Department of Chemistry, University of Utah, 315 S 1400 E Rm 2020, Salt Lake City, UT 84112, USA.
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8
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González Plaza JJ. Small RNAs as Fundamental Players in the Transference of Information During Bacterial Infectious Diseases. Front Mol Biosci 2020; 7:101. [PMID: 32613006 PMCID: PMC7308464 DOI: 10.3389/fmolb.2020.00101] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 05/04/2020] [Indexed: 12/24/2022] Open
Abstract
Communication shapes life on Earth. Transference of information has played a paramount role on the evolution of all living or extinct organisms since the appearance of life. Success or failure in this process will determine the prevalence or disappearance of a certain set of genes, the basis of Darwinian paradigm. Among different molecules used for transmission or reception of information, RNA plays a key role. For instance, the early precursors of life were information molecules based in primitive RNA forms. A growing field of research has focused on the contribution of small non-coding RNA forms due to its role on infectious diseases. These are short RNA species that carry out regulatory tasks in cis or trans. Small RNAs have shown their relevance in fine tuning the expression and activity of important regulators of essential genes for bacteria. Regulation of targets occurs through a plethora of mechanisms, including mRNA stabilization/destabilization, driving target mRNAs to degradation, or direct binding to regulatory proteins. Different studies have been conducted during the interplay of pathogenic bacteria with several hosts, including humans, animals, or plants. The sRNAs help the invader to quickly adapt to the change in environmental conditions when it enters in the host, or passes to a free state. The adaptation is achieved by direct targeting of the pathogen genes, or subversion of the host immune system. Pathogens trigger also an immune response in the host, which has been shown as well to be regulated by a wide range of sRNAs. This review focuses on the most recent host-pathogen interaction studies during bacterial infectious diseases, providing the perspective of the pathogen.
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Affiliation(s)
- Juan José González Plaza
- Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czechia
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9
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Engineering salt tolerance of photosynthetic cyanobacteria for seawater utilization. Biotechnol Adv 2020; 43:107578. [PMID: 32553809 DOI: 10.1016/j.biotechadv.2020.107578] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/17/2020] [Accepted: 06/05/2020] [Indexed: 02/04/2023]
Abstract
Photosynthetic cyanobacteria are capable of utilizing sunlight and CO2 as sole energy and carbon sources, respectively. With genetically modified cyanobacteria being used as a promising chassis to produce various biofuels and chemicals in recent years, future large-scale cultivation of cyanobacteria would have to be performed in seawater, since freshwater supplies of the earth are very limiting. However, high concentration of salt is known to inhibit the growth of cyanobacteria. This review aims at comparing the mechanisms that different cyanobacteria respond to salt stress, and then summarizing various strategies of developing salt-tolerant cyanobacteria for seawater cultivation, including the utilization of halotolerant cyanobacteria and the engineering of salt-tolerant freshwater cyanobacteria. In addition, the challenges and potential strategies related to further improving salt tolerance in cyanobacteria are also discussed.
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Thairu MW, Hansen AK. It's a small, small world: unravelling the role and evolution of small RNAs in organelle and endosymbiont genomes. FEMS Microbiol Lett 2019; 366:5371121. [PMID: 30844054 DOI: 10.1093/femsle/fnz049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 03/05/2019] [Indexed: 12/19/2022] Open
Abstract
Organelles and host-restricted bacterial symbionts are characterized by having highly reduced genomes that lack many key regulatory genes and elements. Thus, it has been hypothesized that the eukaryotic nuclear genome is primarily responsible for regulating these symbioses. However, with the discovery of organelle- and symbiont-expressed small RNAs (sRNAs) there is emerging evidence that these sRNAs may play a role in gene regulation as well. Here, we compare the diversity of organelle and bacterial symbiont sRNAs recently identified using genome-enabled '-omic' technologies and discuss their potential role in gene regulation. We also discuss how the genome architecture of small genomes may influence the evolution of these sRNAs and their potential function. Additionally, these new studies suggest that some sRNAs are conserved within organelle and symbiont taxa and respond to changes in the environment and/or their hosts. In summary, these results suggest that organelle and symbiont sRNAs may play a role in gene regulation in addition to nuclear-encoded host mechanisms.
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Affiliation(s)
- Margaret W Thairu
- Department of Entomology, University of California, Riverside, Riverside, CA, USA
| | - Allison K Hansen
- Department of Entomology, University of California, Riverside, Riverside, CA, USA
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11
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Muro-Pastor AM, Hess WR. Regulatory RNA at the crossroads of carbon and nitrogen metabolism in photosynthetic cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1863:194477. [PMID: 31884117 DOI: 10.1016/j.bbagrm.2019.194477] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 12/16/2019] [Accepted: 12/22/2019] [Indexed: 12/17/2022]
Abstract
Cyanobacteria are photosynthetic bacteria that populate widely different habitats. Accordingly, cyanobacteria exhibit a wide spectrum of lifestyles, physiologies, and morphologies and possess genome sizes and gene numbers which may vary by up to a factor of ten within the phylum. Consequently, large differences exist between individual species in the size and complexity of their regulatory networks. Several non-coding RNAs have been identified that play crucial roles in the acclimation responses of cyanobacteria to changes in the environment. Some of these regulatory RNAs are conserved throughout the cyanobacterial phylum, while others exist only in a few taxa. Here we give an overview on characterized regulatory RNAs in cyanobacteria, with a focus on regulators of photosynthesis, carbon and nitrogen metabolism. However, chances are high that these regulators represent just the tip of the iceberg.
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Affiliation(s)
- Alicia M Muro-Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, E-41092 Sevilla, Spain
| | - Wolfgang R Hess
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, D-79104 Freiburg, Germany; University of Freiburg, Freiburg Institute for Advanced Studies, Albertstr. 19, D-79104 Freiburg, Germany.
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12
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Kirsch F, Klähn S, Hagemann M. Salt-Regulated Accumulation of the Compatible Solutes Sucrose and Glucosylglycerol in Cyanobacteria and Its Biotechnological Potential. Front Microbiol 2019; 10:2139. [PMID: 31572343 PMCID: PMC6753628 DOI: 10.3389/fmicb.2019.02139] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 08/30/2019] [Indexed: 12/11/2022] Open
Abstract
Cyanobacteria are prokaryotes that can assimilate inorganic carbon via oxygenic photosynthesis, which results in the formation of organic compounds essentially from CO2, water, and light. Increasing concerns regarding the increase in atmospheric CO2 due to fossil energy usage fueled the idea of a photosynthesis-driven and CO2-neutral, i.e., cyanobacteria-based biotechnology. The ability of various cyanobacteria to tolerate high and/or fluctuating salinities attenuates the requirement of freshwater for their cultivation, which makes these organisms even more interesting regarding a sustainable utilization of natural resources. However, those applications require a detailed knowledge of the processes involved in salt acclimation. Here, we review the current state of our knowledge on the regulation of compatible solute accumulation in cyanobacteria. The model organism Synechocystis sp. PCC 6803 responds to increasing salinities mainly by the accumulation of glucosylglycerol (GG) and sucrose. After exposure toward increased salt concentrations, the accumulation of the main compatible solute GG is achieved by de novo synthesis. The key target of regulation is the enzyme GG-phosphate synthase (GgpS) and involves transcriptional, posttranscriptional, and biochemical mechanisms. Recently, the GG-degrading enzyme GG hydrolase A (GghA) was identified, which is particularly important for GG degradation during exposure to decreasing salinities. The inversely ion-regulated activities of GgpS and GghA could represent the main model for effectively tuning GG steady state levels according to external salinities. Similar to GG, the intracellular amount of sucrose is also salt-regulated and seems to be determined by the balance of sucrose synthesis via sucrose-phosphate synthase (Sps) and its degradation via invertase (Inv). In addition to their role as stress protectants, both compatible solutes also represent promising targets for biotechnology. Hence, the increasing knowledge on the regulation of compatible solute accumulation not only improves our understanding of the stress physiology of cyanobacteria but will also support their future biotechnological applications.
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Affiliation(s)
- Friedrich Kirsch
- Department of Plant Physiology, Institute for Biosciences, University of Rostock, Rostock, Germany
| | - Stephan Klähn
- Department of Solar Materials, Helmholtz-Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute for Biosciences, University of Rostock, Rostock, Germany
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