Overexpression of squalene synthase in Eleutherococcus senticosus increases phytosterol and triterpene accumulation

Seo, Jinwook; Jeong, Jae−Hun; Shin, Cha‐Gyun; Lo, Seog-Cho; Han, Seong-Soo; Yu, Kee-Won; Harada, Emiko; Han, Jeong-Yeon; Choi, Yoon E.

doi:10.1016/j.phytochem.2005.02.016

Cited by 140 publications

(79 citation statements)

References 29 publications

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“…This result is consistent with the increases in the total phytosterols including -sitosterol and stigmasterol reported in SS-overexpressed P. ginseng (Lee et al 2004) and Eleutherococcus senticosus (Seo et al 2005). In the EtSS-overexpressed calli SS103 and SS104, the amount of stigmasterol increased, while those of cycloartenol and 24-methylenecycloartanol decreased (Table 1).…”

Section: Discussionsupporting

confidence: 90%

Cloning and characterization of a squalene synthase gene from a petroleum plant, Euphorbia tirucalli L.

Uchida

Yamashita

Kajikawa

et al. 2009

Planta

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Euphorbia tirucalli L., which is also known as a petroleum plant, produces a large amount of phytosterols and triterpenes. During their biosynthesis, squalene synthase converts two molecules of the hydrophilic substrate farnesyl diphosphate into a hydrophobic product, squalene. An E. tirucalli cDNA clone of a putative squalene synthase gene (EtSS) was isolated by RT-PCR followed by 5'- and 3'-RACE. The restriction fragment polymorphisms revealed by Southern blot analysis suggest that EtSS is a single copy gene. The glycine at the 287th residue from the N-terminal end of domain C has replaced alanine, which is conserved among all the other SS sequences deposited in the Genbank database. The N-terminal 380 residues of the hydrophilic sequence was expressed as a peptide-tagged protein in E. coli, and the resultant bacterial crude extract was incubated with farnesyl diphosphate and NADPH. GC-MS analysis showed that squalene was detected in the in vitro reaction mixture. E. tirucalli transgenic callus lines, in which EtSS was overexpressed, accumulated increased amounts of phytosterols as compared with that of wild type callus. RT-PCR analysis of wild type E. tirucalli plants revealed that the EtSS transcript accumulated in almost equal amounts in the stems and the leaves with a stalk, while a lower amount was detected in the roots. In situ hybridization analysis revealed that prominent antisense-probe signal was detected in the cambia within bundle sheathes. These results indicate that EtSS functions prominently in cambia, which are located adjacent to conductive tubes, and that this gene plays important roles in phytosterol accumulation in petroleum plants.

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Section: Discussionsupporting

confidence: 90%

Cloning and characterization of a squalene synthase gene from a petroleum plant, Euphorbia tirucalli L.

Uchida

Yamashita

Kajikawa

et al. 2009

Planta

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“…An enhancement of phytosterol and saponin accumulation by SS gene overexpression has been reported in some species, including P. ginseng (Lee et al 2004), Eleutherococcus senticosus (Seo et al 2005). In sense transgenic lines overexpressing the BfSS1 gene, accumulation of b-AS mRNA and CAS mRNA was suppressed and slightly increased, respectively (Fig.…”

Section: Discussionmentioning

confidence: 69%

Gene regulation patterns in triterpene biosynthetic pathway driven by overexpression of squalene synthase and methyl jasmonate elicitation in Bupleurum falcatum

Kim

Cho

Park

et al. 2010

Planta

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The root of Bupleurum falcatum L. (Apiaceae) has long been one of the most important traditional herbal medicines in Asian countries. A group of triterpene saponins (saikosaponins) are the major constituents of this plant. Squalene synthase (SS) may play a regulatory role in directing triterpene intermediates and sterol pathways. Here, we investigated the regulatory role of the squalene synthase (BfSS1) gene in the biosynthesis of phytosterol and triterpene in B. falcatum. BfSS1 mRNA accumulated ubiquitously in plant organs and markedly increased in roots after treatment with methyl jasmonate (MeJA), ABA and ethephon. Transgenic B. falcatum constructs overexpressing BfSS1 in the sense and antisense orientations were assembled using the Agrobacterium-mediated method. Transgenic roots overexpressing BfSS1 in the sense orientation resulted in enhanced production of both phytosterol and saikosaponins. Overexpression of the BfSS1 gene in the sense orientation increased the mRNA accumulation of downstream genes such as squalene epoxidase and cycloartenol synthase but unexpectedly decreased the mRNA levels of β-amyrin synthase (β-AS), a triterpene synthase mRNA. MeJA treatment of wild-type roots strongly stimulated β-AS mRNA accumulation and saikosaponin production but suppressed phytosterol production. MeJA treatment of transgenic roots overexpressing BfSS1 in the sense orientation failed to stimulate β-AS mRNA accumulation but still enhanced saikosaponin and phytosterol production. These results indicate that overexpression of BfSS1 in B. falcatum regulates more powerfully the downstream genes than elicitor (MeJA) treatment in triterpene and phytosterol biosynthesis.

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“…The transgenic periwinkle (Catharanthus roseus) cell culture, expressing an alkaloid biosynthetic gene with re-engineered substrate specificity, acquired the capacity to produce various exogenous alkaloids when co-cultured with the substrates [60]. Overexpression of squalene synthase genes in Panax ginseng [61] and Eleutherococcus senticosus [62] led to the enhanced accumulation of phytosterols and triterpenes. Moreover, overexpressing squalene synthase in Bupleurum falcatum resulted in enhanced production of both phytosterol and saikosaponins and increased the expression of downstream genes including squalene epoxidase and cycloartenol synthase [63].…”

Section: Metabolic Engineeringmentioning

confidence: 99%

A comprehensive review on the phytochemical and pharmacological aspects of Podophyllum hexandrum: a high value medicinal plant

Rather¹

2016

Adv Biomed Pharma

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Podophyllum hexandrum Royle, a rhizomatous perennial herb from the Berberidaceae family, is a highly reputed medicinal plant known for its lignan, podophyllotoxin. Podophyllotoxin and its semisynthetic derivativatives are potent anticancer agents. The semisynthetic analogues of podophyllotoxin are also used in the treatment of lung cancer, testicular cancer, neuroblastoma, hepatoma and other tumor diseases. While Podophyllotoxin acts as an inhibitor of the microtubule assembly, the cytotoxic action of its derevatives is based on the inhibition of topoisomerase. Owing to the ever-increasing demand of Podophyllum hexandrum for podophyllotoxin, it has been subjected to heavy collection from the wild. The anti-cancer lignan derivative podophyllotoxin is biosynthesized at very low quantities in intact Podophyllum hexandrum plant and the whole plant is harvested to isolate the bioactive lignan adding to the threats that the plant is currently facing. Therefore, biotechnological production of podophyllotoxin has been considered essential. The present review gives a brief introduction about the phytochemistry, pharmacology and biosynthesis of podophyllotoxin and also discusses the potential of biotechnology for production of podophyllotoxin to meet the increasing demand of this highly valued plant metabolite.

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Overexpression of squalene synthase in Eleutherococcus senticosus increases phytosterol and triterpene accumulation

Cited by 140 publications

References 29 publications

Cloning and characterization of a squalene synthase gene from a petroleum plant, Euphorbia tirucalli L.

Cloning and characterization of a squalene synthase gene from a petroleum plant, Euphorbia tirucalli L.

Gene regulation patterns in triterpene biosynthetic pathway driven by overexpression of squalene synthase and methyl jasmonate elicitation in Bupleurum falcatum

A comprehensive review on the phytochemical and pharmacological aspects of Podophyllum hexandrum: a high value medicinal plant

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