“…By combining the genetic manipulation of the ectopic expression of AtPAP1 and co-suppression of the cinnamoyl-CoA reductase and caffeic acid O-methyltransferase genes in S . miltiorrhiza , a 2.49-fold increase of RA was obtained 66 . Our data showed that overexpression of the PvTAT in hairy roots increased TAT expression, followed by increased enzyme activity, and and 31–83% increases in RA accumulation (Fig.…”
Rosmarinic acid (RA) and its derivants are medicinal compounds that comprise the active components of several therapeutics. We isolated and characterised a tyrosine aminotransferase of Prunella vulgaris (PvTAT). Deduced PvTAT was markedly homologous to other known/putative plant TATs. Cytoplasmic localisation of PvTAT was observed in tobacco protoplasts. Recombinantly expressed and purified PvTAT had substrates preference for L-tyrosine and phenylpyruvate, with apparent K
m of 0.40 and 0.48 mM, and favoured the conversion of tyrosine to 4-hydroxyphenylpyruvate. In vivo activity was confirmed by functional restoration of the Escherichia coli tyrosine auxotrophic mutant DL39. Agrobacterium rhizogenes-mediated antisense/sense expression of PvTAT in hairy roots was used to evaluate the contribution of PvTAT to RA synthesis. PvTAT were reduced by 46–95% and RA were decreased by 36–91% with low catalytic activity in antisense transgenic hairy root lines; furthermore, PvTAT were increased 0.77–2.6-fold with increased 1.3–1.8-fold RA and strong catalytic activity in sense transgenic hairy root lines compared with wild-type counterparts. The comprehensive physiological and catalytic evidence fills in the gap in RA-producing plants which didn’t provide evidence for TAT expression and catalytic activities in vitro and in vivo. That also highlights RA biosynthesis pathway in P. vulgaris and provides useful information to engineer natural products.
“…By combining the genetic manipulation of the ectopic expression of AtPAP1 and co-suppression of the cinnamoyl-CoA reductase and caffeic acid O-methyltransferase genes in S . miltiorrhiza , a 2.49-fold increase of RA was obtained 66 . Our data showed that overexpression of the PvTAT in hairy roots increased TAT expression, followed by increased enzyme activity, and and 31–83% increases in RA accumulation (Fig.…”
Rosmarinic acid (RA) and its derivants are medicinal compounds that comprise the active components of several therapeutics. We isolated and characterised a tyrosine aminotransferase of Prunella vulgaris (PvTAT). Deduced PvTAT was markedly homologous to other known/putative plant TATs. Cytoplasmic localisation of PvTAT was observed in tobacco protoplasts. Recombinantly expressed and purified PvTAT had substrates preference for L-tyrosine and phenylpyruvate, with apparent K
m of 0.40 and 0.48 mM, and favoured the conversion of tyrosine to 4-hydroxyphenylpyruvate. In vivo activity was confirmed by functional restoration of the Escherichia coli tyrosine auxotrophic mutant DL39. Agrobacterium rhizogenes-mediated antisense/sense expression of PvTAT in hairy roots was used to evaluate the contribution of PvTAT to RA synthesis. PvTAT were reduced by 46–95% and RA were decreased by 36–91% with low catalytic activity in antisense transgenic hairy root lines; furthermore, PvTAT were increased 0.77–2.6-fold with increased 1.3–1.8-fold RA and strong catalytic activity in sense transgenic hairy root lines compared with wild-type counterparts. The comprehensive physiological and catalytic evidence fills in the gap in RA-producing plants which didn’t provide evidence for TAT expression and catalytic activities in vitro and in vivo. That also highlights RA biosynthesis pathway in P. vulgaris and provides useful information to engineer natural products.
“…The altered transcription of SmMYB36 leads to changed expression of biosynthetic pathway genes and modulated the metabolic flux shift from phenolic acid accumulation to tanshinone accumulation. The regulation of metabolic flux has been achieved by the altered expression of secondary metabolic pathway genes 21–24 and transcription factors 8, 13, 58–60 in S. miltiorrhiza . The regulation of transcription factors is thought to function by interacting with cis -elements of secondary metabolic pathway genes.…”
Section: Discussionmentioning
confidence: 99%
“…Next, IPP is transformed into diterpenoids as catalysed by geranylgeranyl diphosphate synthase (GGPPS), copalyl diphosphate synthase (CPS), kaurene synthase-like (KSL), CYP and other unknown enzymes 15, 19, 20 . According to the stated pathway, the content of the aimed metabolites was increased through key enzyme gene overexpression of the biosynthetic pathways 21–23 and gene expression suppression of competitive pathways 23, 24 in S. miltiorrhiza hairy roots or plants.Figure 1The model for tanshinone and phenolic acid biosynthesis regulation by SmMYB36.
…”
Phenolic acids and tanshinones are two major bioactive components in Salvia miltiorrhiza Bunge. A novel endogenous R2R3-MYB transcription factor, SmMYB36, was identified in this research. This transcript factor can simultaneously influence the content of two types of components in SmMYB36 overexpression hairy roots. SmMYB36 was mainly localized in the nucleus of onion epidermis and it has transactivation activity. The overexpression of SmMYB36 promoted tanshinone accumulation but inhibited phenolic acid and flavonoid biosynthesis in Salvia miltiorrhiza hairy roots. The altered metabolite content was due to changed metabolic flow which was regulated by transcript expression of metabolic pathway genes. The gene transcription levels of the phenylpropanoid general pathway, tyrosine derived pathway, methylerythritol phosphate pathway and downstream tanshinone biosynthetic pathway changed significantly due to the overexpression of SmMYB36. The wide distribution of MYB binding elements (MBS, MRE, MBSI and MBSII) and electrophoretic mobility shift assay results indicated that SmMYB36 may be an effective tool to regulate metabolic flux shifts.
“…Therefore, it is important to improve the stress resistance and adaptability of this plant. However, to date, efforts to improve this plant by genetic engineering have mainly focused on increasing the contents of active ingredients such as tanshinone and phenolic acids (Zhang Y. et al, 2014; Zhao et al, 2015). By contrast, few studies have focused on improving the stress tolerance of S. miltiorrhiza using transgenic methods (Wang et al, 2012; Wu et al, 2014).…”
Dehydration responsive element binding proteins are transcription factors of the plant-specific AP2 family, many of which contribute to abiotic stress responses in several plant species. We investigated the possibility of increasing drought tolerance in the traditional Chinese medicinal herb, Salvia miltiorrhiza, through modulating the transcriptional regulation of AtDREB1C in transgenic plants under the control of a constitutive (35S) or drought-inducible (RD29A) promoter. AtDREB1C transgenic S. miltiorrhiza plants showed increased survival under severe drought conditions compared to the non-transgenic wild-type (WT) control. However, transgenic plants with constitutive overexpression of AtDREB1C showed considerable dwarfing relative to WT. Physiological tests suggested that the higher chlorophyll content, photosynthetic capacity, and superoxide dismutase, peroxidase, and catalase activity in the transgenic plants enhanced plant drought stress resistance compared to WT. Transcriptome analysis of S. miltiorrhiza following drought stress identified a number of differentially expressed genes (DEGs) between the AtDREB1C transgenic lines and WT. These DEGs are involved in photosynthesis, plant hormone signal transduction, phenylpropanoid biosynthesis, ribosome, starch and sucrose metabolism, and other metabolic pathways. The modified pathways involved in plant hormone signaling are thought to be one of the main causes of the increased drought tolerance of AtDREB1C transgenic S. miltiorrhiza plants.
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