Synthesis, Regulation and Degradation of Carotenoids Under Low Level UV-B Radiation in the Filamentous Cyanobacterium Chlorogloeopsis fritschii PCC 6912

Llewellyn, Carole A.; Airs, Ruth L.; Farnham, Garry; Greig, Carolyn

doi:10.3389/fmicb.2020.00163

Cited by 32 publications

(15 citation statements)

References 62 publications

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“…Furthermore, metabolic feedback regulation probably plays an important role, both within the isoprenoid biosynthetic pathway and the carotenoid pathway ( Cazzonelli and Pogson, 2010 ). Since carotenoids are heavily involved in the response to light stress ( Llewellyn et al, 2020 ; Steiger et al, 1999 ), reduced carotenoid content could lead to the accumulation of ROS, thereby possibly triggering increased flux towards GGPP.…”

Section: Resultsmentioning

confidence: 99%

Metabolic engineering of Synechocystis sp. PCC 6803 for the photoproduction of the sesquiterpene valencene

Dietsch

Behle

Westhoff

et al. 2021

Metabolic Engineering Communications

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Cyanobacteria are extremely adaptable, fast-growing, solar-powered cell factories that, like plants, are able to convert carbon dioxide into sugar and oxygen and thereby produce a large number of important compounds. Due to their unique phototrophy-associated physiological properties, i.e. naturally occurring isoprenoid metabolic pathway, they represent a highly promising platform for terpenoid biosynthesis. Here, we implemented a carefully devised engineering strategy to boost the biosynthesis of commercially attractive plant sequiterpenes, in particular valencene. Sesquiterpenes are a diverse group of bioactive metabolites, mainly produced in higher plants, but with often low concentrations and expensive downstream extraction. In this work we successfully demonstrate a multi-component engineering approach towards the photosynthetic production of valencene in the cyanobacterium Synechocystis sp. PCC 6803. First, we improved the flux towards valencene by markerless genomic deletions of shc and sqs . Secondly, we downregulated the formation of carotenoids, which are essential for viability of the cell, using CRISPRi on crtE . Finally, we intended to increase the spatial proximity of the two enzymes, ispA and CnVS , involved in valencene formation by creating an operon construct, as well as a fusion protein. Combining the most successful strategies resulted in a valencene production of 19 mg/g DCW in Synechocystis . In this work, we have devised a useful platform for future engineering steps.

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Section: Resultsmentioning

confidence: 99%

Metabolic engineering of Synechocystis sp. PCC 6803 for the photoproduction of the sesquiterpene valencene

Dietsch

Behle

Westhoff

et al. 2021

Metabolic Engineering Communications

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show abstract

“…Our results highlight the complex finely tuned Methods UV-B light exposure experiment. Experimental set up for the low level UV-B light exposure was as previously reported 44 . Chlorogloeopsis fritschii (Mitra) PCC 6912 was inoculated at 1:50 dilution from a master culture and cultivated in 5 L Erlenmeyer flasks containing 2 L BG11 media with 10 mM HEPES buffer at pH 7.5.…”

Section: Resultsmentioning

confidence: 99%

Mycosporine-like amino acid and aromatic amino acid transcriptome response to UV and far-red light in the cyanobacterium Chlorogloeopsis fritschii PCC 6912

Llewellyn

Greig

Silkina

et al. 2020

Sci Rep

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The “UV sunscreen” compounds, the mycosporine-like amino acids (MAAs) are widely reported in cyanobacteria and are known to be induced under ultra-violet (UV) light. However, the impact of far red (FR) light on MAA biosynthesis has not been studied. We report results from two experiments measuring transcriptional regulation of MAA and aromatic amino acid pathways in the filamentous cyanobacterium Chlorogloeopsis fritschii PCC 6912. The first experiment, comparing UV with white light, shows the expected upregulation of the characteristic MAA mys gene cluster. The second experiment, comparing FR with white light, shows that three genes of the four mys gene cluster encoding up to mycosporine-glycine are also upregulated under FR light. This is a new discovery. We observed corresponding increases in MAAs under FR light using HPLC analysis. The tryptophan pathway was upregulated under UV, with no change under FR. The tyrosine and phenylalanine pathways were unaltered under both conditions. However, nitrate ABC transporter genes were upregulated under UV and FR light indicating increased nitrogen requirement under both light conditions. The discovery that MAAs are upregulated under FR light supports MAAs playing a role in photon dissipation and thermoregulation with a possible role in contributing to Earth surface temperature regulation.

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“…Moreover, the exposition to UV-B and UV-C radiation are also demonstrated to affect the expression of genes directly related to carotenogenesis. For instance, UV-B has shown a regulator effect of the initial steps of carotenoid synthesis, stimulating the PSY and lycopene biosynthesis in filamentous cyanobacterium Chlorogloeopsis fritschii PCC 6912 after 9.5 kJ m −2 (4 h) and 37.8 kJ m −2 (4 h/d during 4 d) [40]. Similarly, this positive effect of UV-B radiation on carotenoid accumulation has been reported in tobacco leaves after 9.75 kJ m −2 for 8 d [41].…”

Section: Discussionmentioning

confidence: 99%

Postharvest UV-B and Photoperiod with Blue + Red LEDs as Strategies to Stimulate Carotenogenesis in Bell Peppers

2021

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Background: Our objective was to evaluate carotenoid accumulation in bell peppers during shelf life under different light conditions. Methods: Fruit stored for 6 d at 7 °C received a 9 kJ m−2 UV-B treatment, while non-UV-treated were used as control (CTRL). Subsequently, all peppers were disposed for a retail sale period of 4 d at 20 °C with a photoperiod of 14 h under fluorescent light (FL) + 10 h under darkness (D), FL, or blue + red LEDs (BR LED). Results: Total antioxidant capacity (TAC) was increased by the UV-B treatment and the photoperiods supplemented with FL and BR LED, which was directly related to the carotenoid content. In fact, CTRL peppers (225 mg β-carotene kg−1) under FL+BR LED showed an increase of ~33% of 13-cis-β-carotene, ~24% of all-trans-β-carotene, and ~27.5% of 9-cis-β-carotene compared to FL + D and FL + FL. Capsaicinoids showed an increase by ~22%, ~38%, and ~27% in the content of capsanthin, capsanthin laurate, and capsanthin esters, respectively, after the UV-B treatment, which was even enhanced after the LED-supplemented photoperiod by ~18% compared to FL+D. Conclusions: Illumination with BR LEDs + UV-B during the retail sale period nights is recommended to increase the bioactive content of bell peppers via carotenoid accumulation to 270 mg β-carotene kg−1.

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Synthesis, Regulation and Degradation of Carotenoids Under Low Level UV-B Radiation in the Filamentous Cyanobacterium Chlorogloeopsis fritschii PCC 6912

Cited by 32 publications

References 62 publications

Metabolic engineering of Synechocystis sp. PCC 6803 for the photoproduction of the sesquiterpene valencene

Metabolic engineering of Synechocystis sp. PCC 6803 for the photoproduction of the sesquiterpene valencene

Mycosporine-like amino acid and aromatic amino acid transcriptome response to UV and far-red light in the cyanobacterium Chlorogloeopsis fritschii PCC 6912

Postharvest UV-B and Photoperiod with Blue + Red LEDs as Strategies to Stimulate Carotenogenesis in Bell Peppers

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