Cloning and expression analysis of calmodulin gene from Pinellia ternate / 中国中药杂志

According to the data of Pinellia ternate transcriptome,two calmodulin genes were cloned and named as Pt Ca M1 and PtCa M2 respectively. The results of bioinformatics analysis showed that Pt Ca Ms genes contained a 450 bp open reading frame,encoding149 amino acids.The identity of the coding sequences was 80%,and the identity of amino acids sequence was 91%. Pt Ca Ms genes contained EF-hand structure domain,belonging to the Ca M families. The Real-time PCR analysed the expression patterns of Pt Ca Ms in different tissues and different treatments. RESULTS:: showed that Pt Ca M1 and Pt Ca M2 gene were the highest expression level in tuber. Under Ca Cl2 treatment,the expressions of Pt Ca Ms were significantly higher than the control. Under EGTA,La Cl3 and TFP treatments,the expression level of Pt Ca Ms decreased gradually. In this study,the Pt Ca Ms gene were successfully cloned from P. ternate,which laid a foundation for the functional characteristic of Pt Ca Ms gene and the synthesis of alkaloids from P. ternata for further study.

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.

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 Ca2+ on photosynthetic parameters of Pinellia ternata and accumulations of active components in heat stress / 中国中药杂志

<p><b>OBJECTIVE</b>To study the effect of exogenous Ca2+ on photosynthetic parameters of Pinellia ternate and accumulations of active components under high temperature stress.</p><p><b>METHOD</b>The pigment contents of P. ternata leaves, photosynthesis parameters and chlorophyll fluorescence parameters of P. ternata leaves, the contents of guanosine, adenosine and polysaccharide in P. ternata tubers were measured based on different concentrations of exogenous Ca2+ in heat stress when the plant height of P. ternata was around 10 cm.</p><p><b>RESULT</b>The contents of total chlorophyll and ratio of chlorophyll a/b were relatively higher by spaying Ca2+. Compared with the control, spaying 6 mmol x L(-1) Ca2+ significantly enhanced the net photosynthetic rate (Pn), transpiration (Tr) and stomatal limitation (L8), but reduced intercellular CO2 concentration (C) in P. ternata leaves. With the increase of Ca2+ concentration, maximal PS II efficiency (Fv/Fm), actual photosynthetic efficiency (Yield) and photochemical quenching coefficient (qP) initially increased and then decreased, however, minimal fluorescence (Fo) and non-photochemical quenching coefficient (NPQ) went down first and then went up. The contents of guanosine and polysaccharide and dry weight of P. ternata tubers showed a tendency of increase after decrease, and the content of adenosine increased with the increase of Ca2+ concentration. The content of guanosine and polysaccharide in P. ternata tubers and its dry weight reached maximum when spaying 6 mmol x L(-1) Ca2+.</p><p><b>CONCLUSION</b>With the treatment of calcium ion, the inhibition of photosynthesis and the damage of PS II system were relieved in heat stress, which increased the production of P. ternata tubers.</p>

Expression pattern of genes involved in tropane alkaloids biosynthesis and tropane alkaloids accumulation in Atropa belladonna / 中国中药杂志

Atropa belladonna is a medicinal plant and main commercial source of tropane alkaloids (TAs) including scopolamine and hyoscyamine, which are anticholine drugs widely used clinically. Based on the high throughput transcriptome sequencing results, the digital expression patterns of UniGenes representing 9 structural genes (ODC, ADC, AIH, CPA, SPDS, PMT, CYP80F1, H6H, TRII) involved in TAs biosynthesis were constructed, and simultaneously expression analysis of 4 released genes in NCBI (PMT, CYP80F1, H6H, TRII) for verification was performed using qPCR, as well as the TAs contents detection in 8 different tissues. Digital expression patterns results suggested that the 4 genes including ODC, ADC, AIH and CPA involved in the upstream pathway of TAs, and the 2 branch pathway genes including SPDS and TRII were found to be expressed in all the detected tissues with high expression level in secondary root. While the 3 TAs-pathway-specific genes including PMT, CYP80F1, H6H were only expressed in secondary roots and primary roots, mainly in secondary roots. The qPCR detection results of PMT, CYP80F1 and H6H were consistent with the digital expression patterns, but their expression levels in primary root were too low to be detected. The highest content of hyoscyamine was found in tender stems (3.364 mg x g(-1)), followed by tender leaves (1.526 mg x g(-1)), roots (1.598 mg x g(-1)), young fruits (1.271 mg x g(-1)) and fruit sepals (1.413 mg x g(-1)). The highest content of scopolamine was detected in fruit sepals (1.003 mg x g(-1)), then followed by tender stems (0.600 mg x g(-1)) and tender leaves (0.601 mg x g(-1)). Both old stems and old leaves had the lowest content of hyoscyamine and scopolamine. The gene expression profile and TAs accumulation indicated that TAs in Atropa belladonna were mainly biosynthesized in secondary root, and then transported and deposited in tender aerial parts. Screening Atropa belladonna secondary root transcriptome database will facilitate unveiling the unknown enzymatic reactions and the mechanisms of transcriptional control.

Enhanced biosynthesis of scopolamine in transgenic Atropa belladonna by overexpression of h6h gene / 中国中药杂志

Transgenic Atropa belladonna with high levels of scopolamine was developed by metabolic engineering. A functional gene involved in the rate limiting enzyme of h6h involved in the biosynthetic pathway of scopolamine was over expressed in A. belladonna via Agrobacterium-mediation. The transgenic plants were culturing till fruiting through micropropogating and acclimating. The integration of the h6h genes into the genomic DNA of transgenic plants were confirmed by genomic polymerase chain reaction (PCR) analysis. Analysis of the difference of plant height, crown width, stem diameter, leaf length, leaf width, branch number and fresh weight was carried out using SPSS software. The content of hyoscyamine and scopolamine in roots, stems, leaves and fruits was determined by HPLC. The investigation of the expression levels of Hnh6h by qPCR. Both Kan(r) and Hnh6h genes were detected in five transgenic lines of A. belladonna plants (A8, A11, A12, C8 and C19), but were not detected in the controls. The plant height, crown width, stem diameter, leaf length, leaf width, branch number and fresh weight of transgenic plants did not decrease by comparison with the non-transgenic ones, and furthermore some agronomic characters of transgenic plants were better than those of the controls. The highest level of scopolamine was found in leaves of transgenic A. belladonna, and the content of scopolamine was also higher than that of hyoscyamine in leaves. The contents of scopolamine of leaves in different transgenic lines were listed in order: C8 > A12 > C19 > A11 > A8, especially, the content of scopolamine in transgenic line C8 was 2.17 mg x g(-1) DW that was 4.2 folds of the non-transgenic ones (0.42 mg x g(-1) DW). The expression of transgenic Hnh6h was detected in all the transgenic plants but not in the control. The highest level of Hnh6h expression was found in transgenic leaves. Overexpression of Hnh6h is able to break the rate limiting steps involved in the downstream pathway of scopolamine biosynthesis, and thus promotes the metabolic flux flowing toward biosynthesis of scopolamine to improve the capacity of scopolamine biosynthesis in transgenic plants. As a result, transgenic plants of A. belladonna with higher level of scopolamine were developed.