• Journal of Applied Biological Chemistry
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• v.42 no.2
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• pp.92-96
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• 1999

To study the regulatory mechanism of isoprenoid (carotenoid) biosynthesis, we have compared the expression patterns of nine isoprenoid biosynthetic genes in Korean red pepper (Capsicum. annuum cv. NocKaung). The expression of geranylgeranyl pyrophosphate synthase gene was initially induced at early ripening stage (I1) and was rather slightly decreased during pepper fruit ripening. The ex-pression of phytoene synthase gene was strongly induced at semi-ripening stage (I2) and the phytoene desaturase transcript was maximally induced at the fully ripened stage (R). Our results suggest that genes encoding two 3-hydroxy-3-methylglutaryl-CoA reductase isozymes (HMGR1 and HMGR2) and farnesyl pyrophosphate synthase might be not so critical in pepper carotenoid biosynthesis but three genes encoding geranylgeranyl pyrophosphate synthase, phytoene synthase and phytoene desaturase were induced in a sequential manner and coordinately regulated during the ripening of pepper fruit.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.226-235
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• 2017

Carotenoids such as phytoene, lycopene, and ${\beta}-carotene$ are used as food colorants, animal feed supplements, and for human nutrition and cosmetic purposes. Previously, we reported the isolation of a novel marine bacterium, Kocuria gwangalliensis, which produces a pink-orange pigment. Phytoene desaturase (CrtI), encoded by the gene crtI, catalyzes lycopene formation from phytoene and is an essential enzyme in the early steps of carotenoid biosynthesis. CrtI is one of the key enzymes regulating carotenoid biosynthesis and has been implicated as a rate-limiting enzyme of the pathway in various carotenoid synthesizing organisms. Here, we report the cloning of the crtI gene responsible for lycopene biosynthesis from K. gwangalliensis. The gene consisted of 1,584 bases encoding 527 amino acid residues. The nucleotide sequence of the crtI gene was compared with that of other species, including Kocuria rhizophila and Myxococcus xanthus, and was found to be well conserved during evolution. An expression plasmid containing the crtI gene was constructed (pCcrt1), and Escherichia coli cells were transformed with this plasmid to produce a recombinant protein of approximately 57 kDa, corresponding to the molecular weight of phytoene desaturase. Lycopene biosynthesis was confirmed when the plasmid pCcrtI was co-transformed into E. coli containing the plasmid pRScrtEB carrying the crtE and crtB genes required for lycopene biosynthesis. The results from this study will provide valuable information on the primary structure of K. gwangalliensis CrtI at the molecular level.

• Korean Journal of Microbiology
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• v.53 no.4
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• pp.347-350
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• 2017

We sequenced the genome of the Sphingobacteriaceae bacterium SH-48 isolated from the Sohan stream in Republic of Korea by using a dilution-to-extinction culturing method. The sequences were assembled into a draft genome containing 5,650,162 bp with a G + C content of 35.4% and 4,856 protein-coding genes in 2 contigs. This strain contains the carotenoid biosynthesis genes crtY, crtZ, crtD, crtI, crtB, and crtH as gene clusters. This genomic information provides new insights into the carotenoid biosynthesis pathway.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2004.06a
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• pp.292-296
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• 2004

• Journal of Microbiology and Biotechnology
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• v.32 no.12
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• pp.1622-1631
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• 2022

Carotenoids, which are natural pigments found abundantly in wide-ranging species, have diverse functions and high industrial potential. The carotenoid biosynthesis pathway is very complex and has multiple branches, while the accumulation of certain metabolites often affects other metabolites in this pathway. The DsLCYB gene that encodes lycopene cyclase was selected in this study to evaluate β-carotene production and the accumulation of β-carotene in the alga Dunaliella salina. Compared with the wild type, the transgenic algal species overexpressed the DsLCYB gene, resulting in a significant enhancement of the total carotenoid content, with the total amount reaching 8.46 mg/g for an increase of up to 1.26-fold. Interestingly, the production of α-carotene in the transformant was not significantly reduced. This result indicated that the regulation of DsLCYB on the metabolic flux distribution of carotenoid biosynthesis is directional. Moreover, the effects of different light-quality conditions on β-carotene production in D. salina strains were investigated. The results showed that the carotenoid components of β-carotene and β-cryptoxanthin were 1.8-fold and 1.23-fold higher than that in the wild type under red light stress, respectively. This suggests that the accumulation of β-carotene under red light conditions is potentially more profitable.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.05a
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• pp.179-180
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• 2002

• Plant Biotechnology Reports
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• v.4 no.2
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• pp.149-155
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• 2010

Expression of the genes for carotenoid bio-synthesis (crt) is dependent on light, but little is known about the underlying mechanism of light sensing and signalling in the cyanobacterium Synechocystis sp. PCC 6803 (hereafter, Synechocystis). In the present study, we investigated the light-induced increase in the transcript levels of Synechocystis crt genes, including phytoene synthase (crtB), phytoene desaturase (crtP), ${\zeta}$-carotene desaturase (crtQ), and ${\beta}$-carotene hydroxylase (crtR), during a darkto-light transition period. During the dark-to-light shift, the increase in the crt transcript levels was not affected by mutations in cyanobacterial photoreceptors, such as phytochromes (cph1, cph2 and cph3) and a cryptochrome-type photoreceptor (ccry), or respiratory electron transport components NDH and Cyd/CtaI. However, treatment with photosynthetic electron transport inhibitors significantly diminished the accumulation of crt gene transcripts. Therefore, the light induction of the Synechocystis crt gene expression is most likely mediated by photosynthetic electron transport rather than by cyanobacterial photoreceptors during the dark-to-light transition.

• Molecules and Cells
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• v.45 no.9
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• pp.660-672
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• 2022

The target of rapamycin complex (TORC) plays a key role in plant cell growth and survival by regulating the gene expression and metabolism according to environmental information. TORC activates transcription, mRNA translation, and anabolic processes under favorable conditions, thereby promoting plant growth and development. Tomato fruit ripening is a complex developmental process promoted by ethylene and specific transcription factors. TORC is known to modulate leaf senescence in tomato. In this study, we investigated the function of TORC in tomato fruit ripening using virus-induced gene silencing (VIGS) of the TORC genes, TOR, lethal with SEC13 protein 8 (LST8), and regulatory-associated protein of TOR (RAPTOR). Quantitative reverse transcription-polymerase chain reaction showed that the expression levels of tomato TORC genes were the highest in the orange stage during fruit development in Micro-Tom tomato. VIGS of these TORC genes using stage 2 tomato accelerated fruit ripening with premature orange/red coloring and decreased fruit growth, when control tobacco rattle virus 2 (TRV2)-myc fruits reached the mature green stage. TORC-deficient fruits showed early accumulation of carotenoid lycopene and reduced cellulose deposition in pericarp cell walls. The early ripening fruits had higher levels of transcripts related to fruit ripening transcription factors, ethylene biosynthesis, carotenoid synthesis, and cell wall modification. Finally, the early ripening phenotype in Micro-Tom tomato was reproduced in the commercial cultivar Moneymaker tomato by VIGS of the TORC genes. Collectively, these results demonstrate that TORC plays an important role in tomato fruit ripening by modulating the transcription of various ripening-related genes.

• Plant Biotechnology Reports
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• v.4 no.4
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• pp.269-280
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• 2010

Lilium ${\times}$ formolongi was genetically engineered by Agrobacterium-mediated transformation with the plasmid pCrtZW-N8idi-crtEBIY, which contains seven enzyme genes under the regulation of the CaMV 35S promoter. In the transformants, ketocarotenoids were detected in both calli and leaves, which showed a strong orange color. In transgenic calli, the total amount of carotenoids [133.3 ${\mu}g/g$ fresh weight (FW)] was 26.1-fold higher than in wild-type calli. The chlorophyll content and photosynthetic efficiency in transgenic orange plantlets were significantly lowered; however, after several months of subculture, they had turned into plantlets with green leaves that showed significant increases in chlorophyll and photosynthetic efficiency. The total carotenoid contents in leaves of transgenic orange and green plantlets were quantified at 102.9 and 135.2 ${\mu}g/g$ FW, respectively, corresponding to 5.6- and 7.4-fold increases over the levels in the wild-type. Ketocarotenoids such as echinenone, canthaxanthin, 3'-hydroxyechinenone, 3-hydroxyechinenone, and astaxanthin were detected in both transgenic calli and orange leaves. A significant change in the type and composition of ketocarotenoids was observed during the transition from orange transgenic plantlets to green plantlets. Although 3'-hydroxyechinenone, 3-hydroxyechinenone, astaxanthin, and adonirubin were absent, and echinenone and canthaxanthin were present at lower levels, interestingly, the upregulation of carotenoid biosynthesis led to an increase in the total carotenoid concentration (+31.4%) in leaves of the transgenic green plantlets.

• Microbiology and Biotechnology Letters
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• v.46 no.2
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• pp.145-153
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• 2018

Among the carotenoid biosynthesis genes, crtI gene encodes the phytoene desaturase (CrtI) enzyme, and phytoene desaturase convert phytoene to lycopene. Phytoene desaturase is involved in the dehydrogenation reaction, in which four single bonds in the phytoene are introduced into a double bond, eliminating eight hydrogen atoms in the process. Phytoene desaturase is one of the key regulating enzyme in carotenoid biosynthetic pathway of various carotenoid biosynthetic organisms. The crtI gene in genomic DNA of Paracoccus haeundaensis was amplified and cloned into a T-vector to analyze the nucleotide sequence. As a result, the crtI gene coding for phytoene desaturase from P. haeundaensis consists of 1,503 base pairs encoding 501 amino acids residues. An expression plasmid containing the crtI gene was constructed, and Escherichia coli cells containing this plasmid produced the recombinant protein of approximately 55 kDa, equivalent to the molecular weight of phytoene desaturase. The expressed protein in cell lysate showed enzymatic activity similar to phytoene desaturase. Phytoene and lycopene were analyzed by HPLC and measured at wavelength of 280 nm and 470 nm, respectively. The $K_m$ values for phytoene and NADPH were $11.1{\mu}M$ and $129.3{\mu}M$, respectively.