Enhancement of tropane alkaloids biosynthesis in Atropa belladonna hariy root by overexpression of HnCYP82M3 and DsTRI genes / 药学学报

Tropane alkaloids (TAs) are a class of anticholinergic drugs widely used in clinical practice and mainly extracted from plant, among which Atopa belladonna is the main commercial drug source. It is of great industrial value to obtain TAs in large quantities by plant metabolic engineering. In TAs pathway, cytochrome oxidase CYP82M3 catalyze the synthesis of tropinone and then tropinone reductase I (TRI) compete with TRII for tropinone to form tropine leading to the TAs synthesis (drainage). In this study, based on the "increasing flow and drainage" metabolic engineering strategy, two genes, namely HnCYP82M3 and DsTRI from Hyoscyamus niger and Datura stramonium, respectively, were overexpressed in the hair roots of A. belladonna, with a view to promote the TAs accumulation. The HnCYP82M3 gene was cloned from the root of H. niger, and it encoded amino acid with 91.7% sequence identity with AbCYP82M3 from A. belladonna. Overexpression of HnCYP82M3 alone did not affect the content of TAs in hair roots of A. belladonna, indicating that CYP82M3 was not a key enzyme in TAs biosynthesis. Simultaneous overexpression of HnCYP82M3 and DsTRI greatly promoted the accumulation of the three TAs, and the contents of hyoscyamine, anisodamine and scopolamine were 4.97 times, 2.83 times and 2.19 times that of the control, respectively, and the increase amplitude was greater than that of single overexpression of DsTRI. This study showed that the "increasing flow and drainage" strategy of enzyme genes co-expression at branch points was a promising metabolic engineering method to effectively improve the biosynthesis of TAs in A. belladonna, and laid a theoretical and technical foundation for the large-scale industrial acquisition of TAs.

Effect of the rolB gene on phenotypic development and tropane alkaloids biosynthesis in Atropa belladonna / 药学学报

The rol genes on pRiA4 plasmid of Agrobacterium rhizogenes are potent genes that promote secondary metabolism. Molecular breeding of Atropa belladonna can be conducted by introducing rol genes to increase tropane alkaloids (TAs) content in A. belladonna. In this study, the rolB gene was overexpressed in A. belladonna plants to study the effect of rolB gene on the biosynthesis of TAs. The phenotype, TAs content and expression levels of key enzyme genes in the pathway of TAs biosynthesis of transgenic A. belladonna were analyzed. The results showed that transgenic A. belladonna had developed root system, enlarged leaves, increased leaf fresh weight, deepened leaf color, enlarged flowers, changed flower shape, reduced pistil height and decreased pollen vitality. The content of TAs in the stems of transgenic A. belladonna was significantly higher than that of the control, and the contents of scopolamine, anisodamine, hyoscyamine can reach 2.11-2.91, 1.23-2.37 and 4.88-5.20 times of the control, respectively. Compared with the control group, the expressions of key enzymes putrescine N-methyltransferase (PMT), type III polyketide synthase (PYKS), tropinone reductase I (TRI), aromatic amino acid aminotransferase 4 (ArAT4), UDP-glycosyltransferase 1 (UGT1) and hyoscyamine 6-β-hydroxylase (H6H) in the TAs biosynthesis pathway were up-regulated, and the expression of tropinone reductase II (TRII) as a metabolic shunting gene was down-regulated. The results indicated that rolB gene enhanced TAs synthesis ability in roots and accumulation in stems of A. belladonna by enhancing metabolic flow of TAs synthesis pathway and weakening the metabolic shunt of competing pathway. This study laid a foundation for molecular breeding of A. belladonna with high-yield TAs content using rolB gene.

Effect of the rolC gene on biosynthesis of tropane alkaloids in Atropa belladonna / 药学学报

Hair roots induced by Agrobacterium rhizogene produce higher levels of secondary metabolites than non-induced plants, and the enhanced metabolic capacity is driven by the rol gene. We hypothesized that rol genes can be utilized to improve the biosynthesis of tropane alkaloids (TAs) in Atropa belladonna. In this study, the rolC gene from Agrobacterium rhizogene pRiA4 plasmid, driven by a CaMV35S promoter, was overexpressed in A. belladonna. The phenotypes, TAs content and transcriptional expression of key genes in TAs biosynthesis were analyzed in transgenic A. belladonna plants. Results show that transgenic A. belladonna exhibited a well-developed root system, male sterility, higher stamen column length than pistil, early flowering, internode shortening, smaller but more flowers, increased axillary buds and lateral buds, decreased apical dominance, and long and narrow leaves as compared to wild-type plants. Transgenic A. belladonna produced more TAs than wild-type plants, with the content of hyoscyamine, anisodamine and scopolamine reaching 2.58, 3.59 and 15.77-fold that of the control group, respectively. The gene expression of putrescine N-methyltransferase (PMT), tropinone reductase I (TRⅠ) and hyoscyamine 6-β-hydroxylase (H6H), key enzymes in TAs biosynthesis, were up-regulated compared with the control group. The above results indicate that the rolC gene enhances TAs biosynthesis in A. belladonna by up-regulating the expression of key enzymes in the TAs biosynthesis pathway, laying a foundation for genetic manipulation of A. belladonna to increase TAs content by increasing rolC gene expression.

Atropa belladonna (Deadly Nightshade) Poisoning in Childhood

ABSTRACT Objective: A very small amount of Atropa belladonna (AB) can lead to serious symptoms of poisoning and can cause death in children. In this study, demographic, clinic and laboratory results of AB poisoning were evaluated. Methods: A total of 108 cases with belladonna poisoning were retrospectively evaluated. At time of admission, age, age groups, gender, signs and symptoms caused by poisoning, duration of stay in hospital, laboratory data, intensive care needs, and applied treatments were recorded. Results: Approximately 44.4% were females and 55.6% were males. While the most common symptoms were xeroderma and flushing, the most frequent findings were tachycardia and mydriasis. Eight patients complained about astasis and five of them were taken into the intensive care unit. Astasis complaint was relatively higher (p < 0.01) in the patients who needed intensive care than those who did not. Creatine kinase levels were relatively higher (p = 0.06) in the intensive care patients as compared to non-intensive care patients. Neostigmine was given to all patients. Five patients, who failed to respond to therapy, were taken into the intensive care and respond to treatment successfully with physostigmine. Conclusion: Atropa belladonna poisoning may seriously progress in the act of late diagnosis and treatment in childhood. Thus, it is crucial to realize that AB poisoning should be taken into consideration in the patients with flushing, xeroderma with mydriasis, tachycardia, tremor, abdominal pain, and fever symptoms. Patients with astasis complaints should be evaluated carefully in terms of intensive care need. Patients with a Glasgow Coma Scale lower than 12 should be observed in the intensive care.

Nitrogen metabolism and secondary metabolism regulation of Atropa belladonna by exogenous NO under NaCl stress / 中国中药杂志

Atropa belladonna seedlings were used as experimental materials and cultivated by soil culture method. Different concentrations(0,0.05,0.1,0.2,0.5 mmol·L~(-1))of NO donor sodium nitroprusside(SNP) were sprayed on the leaves. The effects of different concentrations of SNP and different treatment time(4,8,12,16 d) on nitrogen metabolism, secondary metabolite content, precursor content of tropane alkaloid synthesis pathway and expression of key enzyme genes under 100 mmol·L~(-1) NaCl stress were studied. The results showed that with the prolongation of salt stress, the nitrogen metabolism and the accumulation of secondary metabolites of A. belladonna were inhibited to some extent. After treatment with different concentrations of exogenous SNP, the ammonium nitrogen content decreased dramatically, and the contents of nitrate nitrogen, free amino acid, soluble protein and the activities of key enzymes of nitrogen metabolism(NR, GS, GDH) were all greatly improved; the contents of precursor amino acids(ornithine, arginine) and polyamines(Put, Spd, Spm) in the secondary metabolic pathway have increased to varying degrees. The qRT-PCR analysis showed that exogenous SNP treatment can effectively promote the high expression of key enzyme genes PMT, TRⅠ and H6H in the secondary metabolic pathway of A. belladonna, and the production of hyoscyamine and scopolamine were increased notably. In summary, the application of appropriate concentration of SNP can effectively alleviate the inhibition of salt stress on the nitrogen metabolism and secondary metabolism of Atropa belladonna, and enhance its salt tolerance. Overall, 0.1 mmol·L~(-1) and 0.2 mmol·L~(-1) SNP treatment achieved the most remarkable effect.

Cloning and functional analysis of AbCYP80F1 gene in Atropa belladonna / 中草药

Objective: To clone AbCYP80F1 gene and its promoter, analyze the Cis-acting elements related to control signals and transcription factors in AbCYP80F1 gene promoter and study the effect of AbCYP80F1 overexpression on scopolamine accumulation in Atropa belladonna. Methods: CYP80F1cDNA from Hyoscyamus niger was used as query sequence to do blastn search in A. belladonna transcriptome database to retrieve homologous unigenes. Full-length of AbCYP80F1 cDNA and gene promoter were acquired by RACE and hiTAIL-PCR, respectively. Agrobacterium rhizogenes-dipping method was adopted to induce AbCYP80F1- overexpressed A. belladonna hairy roots, and scopolamine content in hairy roots was detected by HPLC. Results: A full-length of 1 675 bp of AbCYP80F1 gene was obtained and the deduced protein had a closed homology with CYP80F1 from Anisodus luridus. A length of 2 000 bp promoter contained Cis-acting elements related to light, anaerobic induction, auxin, MeJA, gibberellins and low temperature, as well as recognition sites of transcription factor of MYB, AP2/ERF, WRKY and bHLH. Overexpression of AbCYP80F1 gene increased the scopolamine content in hairy roots of A. belladonna by an average of 1.8 times. Conclusion: AbCYP80F1 is a secondary root-specific gene in scopolamine biosynthetic pathway and its overexpression can enhance scopolamine accumulation. Expression of AbCYP80F1 may be regulated by WRKY and bHLH transcription factors.

Effects of methyl jasmonate on metabolism of topical alkaloids and expression of relate genes in Atropa belladonna / 中国中药杂志

Hyoscyamine and scopolamine are important secondary metabolites of tropane alkaloid in Atropa belladonna with pharmacological values in many aspects.In this study, the seedlings of A.belladonna were planted by soil culture and treated with different concentrations of methyl jasmonate (MeJA). The contents of hyoscyamine and scopolamine,the upstream products in alkaloid synthesis,and the expression levels of key enzyme genes PMT, TR Ⅰ and H6H in secondary metabolites of A. belladonna seedlings were measured to clarify the mechanism of MeJA regulating alkaloids synthesis.The results showed that MeJA(200 μmol·L⁻¹) treatment was more favorable for the accumulation of alkaloids.The content of putrescine was almost consistent with the change of key enzymes activities in the synthesis of putrescine,the both increased first and then decreased with the increased MeJA concentration and the content of putrescine reached the highest at 200 μmol·L⁻¹ MeJA.Further detection of gene expression of PMT, TR Ⅰ and H6H in TAs synthesis pathway showed that no significant trend in PMT gene expression levels.The expression levels of TR Ⅰ and H6H in leaves and roots under 200 μmol·L⁻¹ MeJA were the highest.It can be speculated that the regulation of the formation of hyoscyamine and scopolamine by MeJA mainly through affecting the expression of key enzyme genes.Appropriate concentration of MeJA increased the gene expression of TR Ⅰ in both leaves and roots as well as H6H in roots,promoting the accumulation of alkaloids and the conversion of hyoscyamine to scopolamine.

Mechanism exploration on nitrogen metabolism and secondary metabolism in Atropa belladonna hairy roots treated with yeast extract / 中国中药杂志

In order to study the mechanism of nitrogen metabolism and secondary metabolism in Atropa belladonna hairy roots treated with yeast extract, yeast extract（YE） was added to the culture medium. Then the changes of physiological and biochemical indexes of A. belladonna hairy roots after treatment with YE were detected. The results are as follows，the activity of key enzymes of nitrogen metabolism changed differently. Compared with the control group (CK), the activity of nitrate reductase (NR) and glutamine synthetase (GS) were significantly increased, while the activity of glutamate dehydrogenase (GDH) was not changed significantly. The content of nitrate nitrogen, ammonium nitrogen had a significant decrease,but the content of soluble protein, free amino acid, total nitrogen are significantly more than CK. Moreover, YE treatment led to the increase of the content precursor amino acids (ornithine and arginine) and precursor putrescine in secondary metabolic pathways of A. belladonna. The expression level of gene putrescine N-methyl transferase (pmt), tropinone reductase-I (trI) and hyoscyamine 6-β-hydroxylase(h6h) all increased in a different rate caused by YE treatment, which eventually led to the increase of the yield of tropane alkaloids. The yield of hyoscyamine and scopolamine were 3.09 and 1.85 folds than that of CK after 16 days treatment time. The results indicated that YE can induce more synthesis of tropane alkaloids by increasing the activity of key enzymes in nitrogen metabolism to provide more synthetic materials for secondary metabolism, meanwhile it regulated the expression level of some genes of key metabolic enzyme to accelerate secondary metabolism.

Effects of nitrogen form on accumulation of alkaloids and expression of relative genes in Atropa belladonna / 中国中药杂志

Hyoscyamine and scopolamine are two main alkaloids in Atropa belladonna with great medicinal value. In this paper, the contents of hyoscyamine and scopolamine, the upstream products in alkaloid synthesis, and the expression levels of key enzyme genes PMT, TRⅠ and H6H in secondary metabolism of A. belladonna seedlings were measured to clarify the mechanism of nitrogen forms regulating alkaloids synthesis.The results showed that the 50/50 (NH⁺₄/NO⁻₃) treatment was more favorable for the accumulation of alkaloids and the conversion of hyoscyamine to scopolamine. The content of putrescine was almost consistent with the change of key enzymes activities in the synthesis of putrescine, they both increased with the rise of ammonium ratio, reaching the highest at 75/25 (NH⁺₄/NO⁻₃). The detection of signaling molecule nitric oxide (NO) showed that the NO concentration decreased with the decrease of nitrate proportion. Further detection of gene expression levels of PMT, TRⅠ and H6H in TAs synthesis pathway showed that a certain amount of ammonium promoted the expression of PMT and H6H in roots. When the ratio of ammonium to nitrate was 50/50, PMT, TRⅠ and H6H in leaves and roots had higher expression levels. It can be speculated that the regulation of the formation of hyoscyamine to scopolamine by nitrogen forms mainly through affecting the expression of key enzyme genes. 50/50 (NH⁺₄/NO⁻₃) treatment increased the gene expression of TRⅠ in both leaves and roots as well as PMT and H6H in roots, promoting the synthesis of putrescine to hyoscyamine and the conversion of hyoscyamine to scopolamine.

Influence of elicitors on effective constituents and expression of key metabolic enzyme genes in hairy roots of Atropa belladonna / 中草药

Objective To improve the yield of the effective medicinal ingredients of Atropa belladonna, to provide economic and efficient method for the actual production of A. belladonna, therefore to provide a basic reference for the related research on the mechanism of secondary metabolism of medicinal plants. Methods In this study, the influences of four kinds of elicitors, including methyl jasmonate (MJ), AgNO3, salicylic acid (SA), yeast extract (YE), on the accumulation of active components and the expression level of key metabolic enzyme genes, including putrescine N-methyl transferase (pmt), tropinone reductase-I (trI), and hyoscyamine-6-β-hydroxylase (h6h), were studied in hairy roots of A. belladonna. 0.5 g fresh hairy roots of A. belladonna were cultivated in B5 liquid medium. 12 d later, these mediums were replaced with the new medium containing one kind of four elicitors. Hairy roots were taken samples after 2 d to mensurate the fresh weight, dry weight, the content of tropane alkaloids, some physiological indexes, and three key genes expression level. Results MJ inhibited the growth and tropane alkaloids accumulation of hairy roots. The gene expression level of pmt and trI also decreased compared with control group (CK). The contents of tropane alkaloids and the expression level of pmt, trI and h6h were all increased compared with CK by the treatment of AgNO3, while the growth of hairy rootswas inhibited; SA contributed to the increased content of hyoscyamine, but with no obvious influence on growth of hairy roots. As to YE, the content of tropane alkaloids and the expression level of pmt, trI, h6h were all increased correspondingly. Further more, YE was benefit for the growth of hairy roots. Conclusion Elicitors had selective influence on growth and tropane alkaloids accumulation in hairy roots of A. belladonna. The best elicitor on accumulation of tropane alkaloids was AgNO3. YE could effectively improve of the growth of hairy and contents of tropane alkaloids. This study concluded that these elicitors influence the secondary metabolism of A. belladonna by regulating and controlling the expression level of some genes of key metabolic Enzyme, which could provide an effective method to enhance the medicinal composition in the culture of hairy roots of A. belladonna.

Overexpression of NtPMT and HnH6H changed hyoscyamine-rich Atropa belladonna to scopolamine-rich varieties / 药学学报

Atropa belladonna L. is the commercial plant material for production of tropane alkaloids, including hyoscyamine and scopolamine. The wild-type Atropa belladonna is characterized by the hyoscyaminerich chemotype, in which the hyoscyamine content is much higher than the scopolamine content. It is the common goal for the pharmaceutical industry to increase the content of scopolamine in A. belladonna. Based on the T0 progeny of transgenic A. belladonna with NtPMT and HnH6H overexpression, T1 progeny of transgenic A. belladonna were obtained through self-pollination and used in a field trial. The 461 bp fragment of NtPMT and the 1 077 bp HnH6H were simultaneously expressed from T1 progeny of transgenic A. belladonna, but were not obtained from the wild-type A. belladonna. At the transcription level, the expression of NtPMT and HnH6H were detected in T1 progeny of transgenic A. belladonna, but were not detected in the wild-type plants. Further, the alkaloids were analyzed by HPLC. In the stems and leaves of T1 progeny of transgenic A. belladonna, hyoscyamine was not detected and scopolamine was detected at very high levels; in the stems and leaves of wild-type A. belladonna, hyoscyamine was detected at much higher levels. In the leaves of T1 progeny of transgenic A. belladonna, the content of scopolamine was 15-36 folds higher than that of wildtype leaves; in the stems of T1 progeny of transgenic A. belladonna, the scopolamine content was 37-108 folds higher than that of wild-type stems. In conclusion, overexpression of NtPMT and HnH6H greatly enhanced conversion of hyoscyamine into high-value scopolamine and improved the commercial value of A. belladonna.

Cloning and expression analysis on arginine decarboxylase genes in Atropa belladonna / 中草药

Objective: To clone the full-length cDNAs encoding arginine decarboxylase (ADC) from Atropa belladonna, and to characterize the genes at the bioinformatics and expression levels. Methods: cDNAs were used as templates, the full-length cDNAs of ADC in A. belladonna was cloned through rapid amplification of cDNA ends (RACE) technique; Bioinformatics analysis of AbADC genes was performed by BLAST and PBIL on line. The expression levels of the two AbADC genes in different tissues as well as under two different types of stresses were detected based on qPCR analysis. Results: Two ADC genes, namely AbADC1 and AbADC2, were cloned from A. belladonna. AbADC1 was 2 817 bp in length that encoded 712 amino acids with the highest identity of 89% with ADC from Solanum tuberosum; The full-length cDNA of AbADC2 was 2 992 bp in length that encoded 715 amino acids with the highest identity of 90% with ADC from Datura stramonium. The expression level of AbADC1 was significantly higher in secondary roots than that in any other organ, while the AbADC2 expression level was higher in main roots than that in other detected organs. The transcriptional levels of both AbADC1 and AbADC2 were not affected under salinity stress; AbADC2 expression decreased under cold stress, while AbADC1 did not. Conclusion: The cloning and characterization of the cDNAs encoding ADC from A. belladonna are reported for the first time, which provides the new candidate genes for engineering biosynthetic pathway of tropane alkaloids.

Increasing Scopolamine content in Hairy Roots of Atropa belladonna using Bioreactor

The aim of this study was to use the, hairy root system for increasing the scopolamine content in Atropa belladonna. Agrobacterium rhizogenes ATCC15834 was utilized to produce hairy roots. The culture was carried out in a 1.5-l bioreactor using the inoculum size of 0.5 g fr. wt of 10-day-old hairy roots and various parameters, including agitation, aeration, conductivity and the consumption of sucrose were evaluated. Results revealed that the highest amount of scopolamine production (1.59 mg/g-1 dry wt) occurred in the bioreactor with aeration and agitation 1.25 vvm (volume per volume per minute) and 70 rpm, respectively. Study of conductivity and the consumption of sucrose showed that the highest amount of sucrose consumption and the highest amount of minerals consumption also was at 1.25 vvm and 70 rpm. Transgenic hairy root lines were confirmed by polymerase chain reaction (PCR).