The role of jasmonic acid in stress resistance of plants: a review / 生物工程学报

Jasmonic acid (JA), a plant endogenously synthesized lipid hormone, plays an important role in response to stress. This manuscript summarized the biosynthesis and metabolism of JA and its related regulatory mechanisms, as well as the signal transduction of JA. The mechanism and regulatory network of JA in plant response to biotic and abiotic stresses were systematically reviewed, with the latest advances highlighted. In addition, this review summarized the signal crosstalk between JA and other hormones in regulating plant resistance to various stresses. Finally, the problems to be solved in the study of plant stress resistance mediated by JA were discussed, and the application of new molecular biological technologies in regulating JA signaling to enhance crop resistance was prospected, with the aim to facilitate future research and application of plant stress resistance.

Transcriptional analysis of Rhazya stricta in response to jasmonic acid

BACKGROUND: Jasmonic acid (JA) is a signal transducer molecule that plays an important role in plant development and stress response; it can also efficiently stimulate secondary metabolism in plant cells. RESULTS: RNA-Seq technology was applied to identify differentially expressed genes and study the time course of gene expression in Rhazya stricta in response to JA. Of more than 288 million total reads, approximately 27% were mapped to genes in the reference genome. Genes involved during the secondary metabolite pathways were up- or downregulated when treated with JA in R. stricta. Functional annotation and pathway analysis of all up- and downregulated genes identified many biological processes and molecular functions. Jasmonic acid biosynthetic, cell wall organization, and chlorophyll metabolic processes were upregulated at days 2, 6, and 12, respectively. Similarly, the molecular functions of calcium-transporting ATPase activity, ADP binding, and protein kinase activity were also upregulated at days 2, 6, and 12, respectively. Time-dependent transcriptional gene expression analysis showed that JA can induce signaling in the phenylpropanoid and aromatic acid pathways. These pathways are responsible for the production of secondary metabolites, which are essential for the development and environmental defense mechanism of R. stricta during stress conditions. CONCLUSIONS: Our results suggested that genes involved in flavonoid biosynthesis and aromatic acid synthesis pathways were upregulated during JA stress. However, monoterpenoid indole alkaloid (MIA) was unaffected by JA treatment. Hence, we can postulate that JA plays an important role in R. stricta during plant development and environmental stress conditions.

Cloning and function analysis of promoter of DcCDPK8 from Dendrobium catenatum / 中国中药杂志

DcCDPK8 involved in abiotic stress such as low temperature and signal transduction of hormones ABA and MeJA,but the transcriptional regulation is still unclear. In order to study the core promoter region of DcCDPK8 gene in Dendrobium catenatum and explore its transcriptional regulation mechanism,the DcCDPK8 gene promoter sequence was cloned by PCR from D. catenatum. Promoter sequence function was studied by fusion of 5 'terminal deletion and GUS gene. The results showed that the promoter sequence of DcCDPK8 gene has a low-temperature responsive element( LTR) between~(-1) 749 bp and-614 bp,two MeJA responsive elements between~(-1) 749 bp and-230 bp,and one ABA responsive elements between-614 bp and-230 bp. Three 5'-end different deletion fragments were constructed to fuse the eukaryotic expression vectors p BI121 with GUS,which were transformed into tobacco leaves. The GUS activity under cold stress treatment was DcCDPK8-p1>DcCDPK8-p2>DcCDPK8-p3. GUS activity under exogenous ABA induction was DcCDPK8-p1>DcCDPK8-p2>DcCDPK8-p3,and GUS activity under exogenous MeJA induction was DcCDPK8-p1>DcCDPK8-p2>DcCDPK8-p3. It is speculated that the ABA response element( ARE) in the promoter sequences of DcCDPK8 is positive regulatory role in response to exogenous ABA,the MeJA cis-acting element plays a negative role in response to exogenous MeJA.

Cloning and functional identification of a new NADPH-cytochrome P450 reductase in Andrographis paniculata / 中国中药杂志

Andrographolide is a main active ingredient in traditional Chinese medicine Andrographis paniculata，with a variety of pharmacological activity，widely used in clinical practice. However its biosynthetic pathway has not been resolved. Cytochrome P450 reductase provides electrons for CYP450 and plays an important role in the CYP450 catalytic process. In this study，the coding sequence of A. paniculata CPR was screened and cloned by homologous alignment，named ApCPR4. The ApCPR4 protein was obtained by prokaryotic expression. After isolation and purification，the enzyme activity was identified . The results showed that ApCPR4 could reduce the cytochrome c and ferricyanide in NADPH-dependent manner. In order to verify its function，ApCPR4 and CYP76AH1 were co-transformed into yeast engineering bacteria. The results showed that ApCPR4 could help CYP76AH1 catalyze the formation of rustols in yeast. Real-time quantitative PCR results showed that the expression of ApCPR4 increased gradually in leaves treated with methyl jasmonate (MeJA). The expression pattern was consistent with the trend of induction and accumulation of andrographolide by MeJA，suggesting that ApCPR4 was associated with biosynthesis of andrographolide.

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.

An oriental melon 9-lipoxygenase gene CmLOX09 response to stresses, hormones, and signal substances / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

In plants, lipoxygenases (LOXs) play a crucial role in biotic and abiotic stresses. In our previous study, five 13-LOX genes of oriental melon were regulated by abiotic stress but it is unclear whether the 9-LOX is involved in biotic and abiotic stresses. The promoter analysis revealed that CmLOX09 (type of 9-LOX) has hormone elements, signal substances, and stress elements. We analyzed the expression of CmLOX09 and its downstream genes-CmHPL and CmAOS-in the leaves of four-leaf stage seedlings of the oriental melon cultivar "Yumeiren" under wound, hormone, and signal substances. CmLOX09, CmHPL, and CmAOS were all induced by wounding. CmLOX09 was induced by auxin (indole acetic acid, IAA) and gibberellins (GA3); however, CmHPL and CmAOS showed differential responses to IAA and GA3. CmLOX09, CmHPL, and CmAOS were all induced by hydrogen peroxide (H2O2) and methyl jasmonate (MeJA), while being inhibited by abscisic acid (ABA) and salicylic acid (SA). CmLOX09, CmHPL, and CmAOS were all induced by the powdery mildew pathogen Podosphaera xanthii. The content of 2-hexynol and 2-hexenal in leaves after MeJA treatment was significantly higher than that in the control. After infection with P. xanthii, the diseased leaves of the oriental melon were divided into four levels-levels 1, 2, 3, and 4. The content of jasmonic acid (JA) in the leaves of levels 1 and 3 was significantly higher than that in the level 0 leaves. In summary, the results suggested that CmLOX09 might play a positive role in the response to MeJA through the hydroperoxide lyase (HPL) pathway to produce C6 alcohols and aldehydes, and in the response to P. xanthii through the allene oxide synthase (AOS) pathway to form JA.

Role of jasmonic acid in improving tolerance of rapeseed (Brassica napus L.) to Cd toxicity / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The well-known detrimental effects of cadmium (Cd) on plants are chloroplast destruction, photosynthetic pigment inhibition, imbalance of essential plant nutrients, and membrane damage. Jasmonic acid (JA) is an alleviator against different stresses such as salinity and drought. However, the functional attributes of JA in plants such as the interactive effects of JA application and Cd on rapeseed in response to heavy metal stress remain unclear. JA at 50 µmol/L was observed in literature to have senescence effects in plants. In the present study, 25 µmol/L JA is observed to be a "stress ameliorating molecule" by improving the tolerance of rapeseed plants to Cd toxicity. JA reduces the Cd uptake in the leaves, thereby reducing membrane damage and malondialdehyde content and increasing the essential nutrient uptake. Furthermore, JA shields the chloroplast against the damaging effects of Cd, thereby increasing gas exchange and photosynthetic pigments. Moreover, JA modulates the antioxidant enzyme activity to strengthen the internal defense system. Our results demonstrate the function of JA in alleviating Cd toxicity and its underlying mechanism. Moreover, JA attenuates the damage of Cd to plants. This study enriches our knowledge regarding the use of and protection provided by JA in Cd stress.

[Changes in nepetalactone content and biochemical traits of catnip [nepeta cataria l.] in response to induction of biostimulants compounds]

Background: The use of organic and biological stimulants at different stages of plant growth may increase growth and yield of plants in addition to reducing environmental stresses

Objective: The aim of this study was to determine the induction effect of various formulations of chitosan, humic acid, and nicgtric acid on nepetalactone content and biochemical traits in catnip

Methods: This study, which was based on a completely randomized design [CRBD], was conducted in the research greenhouse of Medicinal Plants Research Institute, ACECR. Treatments consisted of: control, citric acid, different concentrations of humic acid, dual combinatorial formulations of chitosan and citric acid, and triple combinatorial formulations of chitosan, citric acid, and humic acid. First, the roots of the transplants were treated before being transferred to the pot. Then, about 20 days after planting, treatments were sprayed on the plants three times - once everylS days

Results: Results showed that the induction of different formulations of humic acid, citric acid, and chitosan had significant effects on plant height [P<0.05], the number of lateral branches, the number of leaves, dry weight of leaves, stems, and shoot, content of soluble sugar, phenols, tannins, flavonoids, and nepetalactone [P<0.01]. The highest amounts - in most morpho-physiological traits - were observed 400 ppm chitosan + 800 ppm humic acid + 400 ppm citric acid treatment. The maximum content of nepetalactone was obtained at 200 ppm chitosan + 800 ppm humic acid + 400 ppm citric acid

Conclusion: The use of biostimulants formulation including humic acid, citric acid, and chitosan had a significant positive effect on improving vegetative characteristics and especially on phytochemical traits of catnip [Nepeta cataria L.]

Anti-inflammatory and membrane stabilizing properties of methyl jasmonate in rats / 中国天然药物

The present investigation was carried out to evaluate anti-inflammatory and membrane stabilizing properties of methyl jasmonate (MJ) in experimental rat models of acute and chronic inflammation. The effects of MJ on acute inflammation were assessed using carrageenan-induced rat's paw edema model. The granuloma air pouch model was employed to evaluate the effects of MJ on chronic inflammation produced by carrageenan in rats. The number of white blood cells (WBC) in pouch exudates was estimated using light microscopy. The levels of biomarkers of oxidative stress, such as malondialdehyde (MDA), glutathione (GSH) and activity of antioxidant enzymes in the exudates, were determined using spectrophotometry. The membrane stabilizing property of MJ was assessed based on inhibition of hemolysis of rat red blood cells (RBC) exposed to hypotonic medium. Our results indicated that MJ (25-100 mg·kg, i.p.) produced significant anti-inflammatory activity in carrageenan-induced paw edema in rats (P < 0.05). MJ reduced the volume of pouch exudates and the number of WBC in carrageenan-induced granulomatous inflammation. It also exhibited potent antioxidant and membrane stabilizing activities. In conclusion, these findings suggest the therapeutic potentials of methyl jasmonate in disease conditions associated with inflammation and its anti-inflammatory activity may be related to its antioxidant and membrane stabilizing activities.

Effects of elicitors on growth of adventitious roots and contents of secondary metabolites in Tripterygium wilfordii Hook. f / 生物工程学报

To study the effects of the extract of fungal elicitor, AgNO3, MeJA and yeast on the growth and content of secondary metabolites of adventitious roots in Tripterygium wilfordii. The above elicitors were supplemented to the medium, the growth and the content of secondary metabolites were measured. When the medium was supplemented with the elicitor Glomerella cingulata or Collectotrichum gloeosporioides, the content of triptolide was increased by 2.24 and 1.93-fold, the alkaloids content was increased by 2.02 and 2.07-fold, respectively. The optimal concentration of G. cingulata was 50 μg/mL for accumulation of triptolide, alkaloids and for the growth of adventitious roots. AgNO3 inhibited the growth of adventitious roots and the accumulation of the alkaloids, whereas it (at 25 μmol/L) increased the accumulation of triptolide by 1.71-fold compared to the control. The growth of adventitious roots, the contents of triptolide and alkaloids were increased 1.04, 1.64 and 2.12-folds, respectively when MeJA was at 50 μmol/L. When the concentration of yeast reached 2 g/L, the content of triptolide increased 1.48-folds. This research demonstrated that supplementation of AgNO3 and yeast enhanced the biosynthesis of triptolide in adventitious roots and the synergism of G. cingulata and MeJA could promote the biosynthesis of both triptolide and alkaloids.

Absolute bioavailability of ginkgolide compounds in rats / 中国中药杂志

To investigate the pharmacokinetic characteristics and absolute bioavailability of ginkgolide A (GA), ginkgolide B (GB) and bilobalide (BB) in rats. In this experiment, a high-performance liquid chromatography-tandem mass spectrometry (LC-MS/ MS) method was established to determine the plasma concentrations of GA, GB and BB in rats after rats were administrated with the three drugs through ig and iv respectively. The main pharmacokinetic parameters and absolute bioavailability of three ginkgolide compounds were obtained by using pharmacokinetic software DAS 2. 0. After the inject of GA, GB and BB, the results showed Cmax at (513.9 ± 116.9), (701.3 ± 76.0), (5,255.6 ± 476.8) µg · L(-1) and AUC0.24h of (960.9 ± 268.5), (779.5 ± 140.6), (7,409.3 ± 1,181.1) µg · h · L(-1), respectively; after the oral administration, the results showed Cmax at (522.9 ± 39.9), (146.8 ± 31.6), (2,711.9 ± 588.9) µg · L(-1) and AUC0-24 h of (1,760.4 ± 300.7), (636.6 ± 180.3), (16,651.4 ± 1,306.5) µg · h · L(-1), respectively. The absolute bioavailability of GA, GB and BB in rats was (61.1 ± 10.4)%, (27.2 ± 7.7)%, (56.2 ± 4.4)%, respectively. The method established in this experiment has a good specificity and sensitivity and so can be used to study the pharmacokinetics and absolute bioavailability of GA, GB and BB in rats.

Expression analyses of BcUGT3 and BcUGT6, and their in vitro expression in Escherichia coli / 中国中药杂志

The tissue-specific and MeJA-induced transcriptional levels of BcUGT3 and BcUGT6 in Bupleurum chinense were analyzed in the present study. The transcriptional levels of BcUGT3 in root, leaf, flower and fruit were similar and they all were higher than those in stem. The transcriptional level of BcUGT6 was the highest in leaf and the lowest in flower among in all tested tissues. With non-treated adventitious roots as control, BcUGT6's transcriptional levels were elevated to nearly 2 folds for 2 h, 8 h, 24 h, 2 d and 4 d in MeJA-treated adventitious roots of B. chinense. It showed that the transcriptional level of BcUGT6 was slightly affected by MeJA. While, BcUGT3's transcriptional levels were gradually elevated, and till 4 d after MeJA treatment, the expression level was about 7 folds than that of non-treated control. Using pET-28a (+), the expressions of two genes was investigated. Induced by IPTG, the target proteins were expressed in E. coli and then purified. All the results obtained in the present study will be helpful for follow-up bio-function analysis of BcUGT3 and BcUGT6.

Effect of methyl jasmonate on salidroside and polysaccharide accumulation in Rhodiola sachalinensis callus / 中国中药杂志

<p><b>OBJECTIVE</b>To provide a new material for producing the Rhodiolasachalinensis products, the effect of methyl jasmonate (MeJA) on callus biomass and effective compound accumulation of Rhodiolasachalinensis was studied.</p><p><b>METHOD</b>The calluses-cultured in 3 L-air lift balloon type bioreactor were treated with MeJA after 20 d of bioreactor culture and the effect of MeJA concentration and treatment days on callus biomass, salidroside or polysaccharide accumulation and superoxide dismutase (SOD) and peroxidase (POD) activities were investigated.</p><p><b>RESULT</b>The callus biomass was not significantly different after MeJA treatment (125) for 0-6 d but obviously decreased after 6 d treatment. The maximum salidroside or polysaccharide contents and SOD or POD activities were found after 4 d treatment of MeJA. MeJA concentration significantly affected callus biomass and effective compound accumulation, biomass decreased at MeJA concentrations higher than 125 μmol x L(-1). However, the effective compound contents were determined at higher MeJA concentration, and the highest salidroside and polysaccharide accumulation was found at 225 and 275 μmol x L(-1) MeJA, respectively and the maximum SOD and POD activities was found at 225 μmol x L(-1) MeJA. The effective compound contents in callus were compared with field-grown plants. Salidroside contents in calluses were 1.1-fold and 2. 4-fold more than in plant roots and stem or leave, respectively. Polysaccharide content in calluses were 3. 6-fold and 8.0-fold more than in plant roots and stem or leave, respectively.</p><p><b>CONCLUSION</b>Salidorside and polysaccharide in Rhodiolasachalinensiscalluses improved by MeJA treatment, 225 μmol x L(-1) MeJA and 4 d treatment were optimal. The effective compound contents in callus were obviously higher than in field-grown plants. Therefore, bioreactor culture is efficient for obtaining mass effective compounds of Rhodiolasachalinensis by culturing calluses. This method could provide an alternative material source for production of Rhodiolasachalinensis products.</p>

Effects of lovastatin, clomazone and methyl jasmonate treatment on the accumulation of purpurin and mollugin in cell suspension cultures of Rubia cordifolia / 中国天然药物

AIM@#To determine the IPP origin of the naphthoquinones (NQs) in Rubia cordifolia, and to evaluate the effects of methyl jasmonate (MeJA) treatment, MEP, and MVA pathway inhibitor treatment on the accumulation of anthraquinones (AQs) and NQs in cell suspension cultures of R. cordifolia.@*METHODS@#Cell suspension cultures of R. cordifolia were established. Specific inhibitors (lovastatin and clomazone) and MeJA were supplied to the media, respectively. Treated cells were sampled every three days. Content determination of purpurin (AQs) and mollugin (NQs) were carried out using RP-HPLC. The yield of the two compounds was compared with the DMSO-supplied group and the possible mechanism was discussed.@*RESULTS@#Lovastatin treatment increased the yield of purpurin and mollugin significantly. Clomazone treatment resulted in a remarkable decrease of both compounds. In the MeJA-treated cells, the purpurin yield increased, meanwhile, the mollugin yield decreased compared with control.@*CONCLUSION@#The IPP origin of mollugin in R. cordifolia cell suspension cultures was likely from the MEP pathway. To explain the different effects of MeJA on AQs and NQs accumulation, studies on the regulation and expression of the genes, especially after prenylation of 1,4-dihydroxy-2-naphthoic acid should be conducted.

Effects of methyl jasmonate on accumulation and release of main tropane alkaloids in liquid cultures of Datura stramonium hairy root / 中国中药杂志

<p><b>OBJECTIVE</b>To study the effects of methyl jasmonate (MJ) on the accumulation and release of main secondary metabolites i. e. scopolamine and hyoscyamine in liquid cultures of Datura stramonium hairy roots.</p><p><b>METHOD</b>After 18 days liquid culture of D. stramonium hairy roots induced by agrobacterium rhizogenes C58C1, the chemical elicitor methyl jasmonate was added into 1/2 MS liquid cultures and scopolamine and hyoscyamine on the day 0, 3, 6, 9 and 12, after dealing with MJ, was determined by HPLC.</p><p><b>RESULT</b>After dealing with MJ on the day 3, 6, 9 and 12,the concentration of scopolamine reached to 0.419, 0.439, 0.431, 0.374 mg x g(-1), respectively, the increase of scopolamine were 1.36, 1.42, 1.17 and 1.12 fold higher than that of the control, respectively. And hyoscyamine reached 1.493, 0.817, 0.723 and 0.698 mg x g(-1), respectively, the increase of hyoscyamine were 2.28, 1.11, 0.63 and 0.70 fold higher than that of the control, respectively.</p><p><b>CONCLUSION</b>MJ could stimulate the accumulation of scopolamine and hyoscyamine (3,6 d) in D. stramonium hairy root and have released them into the culture medium.</p>

Research on the adipose-derived stem cells combined with the extract of Eucommiol scaffold material to repair the rabbit mandible defect / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of Eucommiol on osteogenic differentiation of adipose-derived stem cells (ADSCs), and the feasibility of applying in mandibular defects repair using ADSCs combined with the extract of Eucommiol scaffold material.</p><p><b>METHODS</b>Forty-eight New Zealand rabbits were randomly divided into four groups and bilateral mandibular defect was prepared. Group A: Implanted the ADSCs combined with the extract of Eucommiol scaffold, group B: Implanted the ADSCs combined with hydroxyapatite materials, group C: Implanted hydroxyapatite materials, group D: The control group. All the experimental animals were sacrificed after 2, 4, 8, 12 weeks. Tissue samples were observed by gross observation, radiographic analysis, hematoxylin-eosin (HE) staining, scanning electron microscope (SEM). The value of imaging analysis and osteogenesis were evaluated. The results were analyzed by SPSS 17.0 statistical software.</p><p><b>RESULTS</b>In vivo imaging and histological staining showed that the healing of bone defect and bone quality in group A was significantly better than those in the other groups. SEM showed well biocompatibility between composite material and tissue without inflammation reaction. By measuring and analyzing the dental CT data and new bone area, the bone in group A was obviously better than those in other groups (P < 0.05).</p><p><b>CONCLUSION</b>The extract of Eucommiol can promote ADSCs into bone cells. The role of ADSCs combined with extract of Eucommiol scaffold materials has significant bone induction. It is expected that this material could become a new composite material and be used to fix the jaw bone defects.</p>

Study on effect of weinaokang and bilobalide on autophagy and neurogenesis induced by focal cerebral ischemia reperfusion / 中国中药杂志

<p><b>OBJECTIVE</b>To observe the protective effect of the Weinaokang (WNK) and its active compound bilobalide on focal cerebral ischemia reperfusion, and their mechanisms.</p><p><b>METHOD</b>The 60-minute middle cerebral artery occlusion (MCAO) was adopted to establish the 24 h-14 d reperfusion model. The expression of Beclin-1 was detected by the Western blotting technique. The transmission electron microscopy was used to observe ultrastructural changes. Neurogenesis was detected by the immunofluorescence staining.</p><p><b>RESULT</b>WNK (20, 10 mg x kg(-1), ig) or its active compound bilobalide (10, 5 mg x kg(-1), ig) could promote the generation of mature neurons (BrdU(+) -MAP-2+) at the ischemic side, and inhibit expression of autophagy-related gene Beclin-1, so as to reduce the neuron injury induced by focal cerebral ischemia reperfusion.</p><p><b>CONCLUSION</b>WNK and its active compound bilobalide can inhibit neuron autophagy and improve neurogenesis in ischemic peripheral area, suggesting that neurogenesis may be the intervention target for WNK to promote self-repairing of ischemic area.</p>

Development of the devices for synthetic biology of triterpene saponins at an early stage: cloning and expression profiling of squalene epoxidase genes in panax notoginseng / 药学学报

Synthetic biology of traditional Chinese medicine (TCM) is a new and developing subject based on the research of secondary metabolite biosynthesis for nature products. The early development of synthetic biology focused on the screening and modification of parts or devices, and establishment of standardized device libraries. Panax notoginseng (Burk.) F.H.Chen is one of the most famous medicinal plants in Panax species. Triterpene saponins have important pharmacological activities in P. notoginseng. Squalene epoxidase (SE) has been considered as a key rate-limiting enzyme in biosynthetic pathways of triterpene saponins and phytosterols. SE acts as one of necessary devices for biosynthesis of triterpene saponins and phytosterols in vitro via synthetic biology approach. Here we cloned two genes encoding squalene epoxidase (PnSE1 and PnSE2) and analyzed the predict amino acid sequences by bioinformatic analysis. Further, we detected the gene expression profiling in different organs and the expression level of SEs in leaves elicited by methyl jasmonate (MeJA) treatment in 4-year-old P notoginseng using real-time quantitative PCR (real-time PCR). The study will provide a foundation for discovery and modification of devices in previous research by TCM synthetic biology. PnSE1 and PnSE2 encoded predicted proteins of 537 and 545 amino acids, respectively. Two amino acid sequences predicted from PnSEs shared strong similarity (79%), but were highly divergent in N-terminal regions (the first 70 amino acids). The genes expression profiling detected by real-time PCR, PnSE1 mRNA abundantly accumulated in all organs, especially in flower. PnSE2 was only weakly expressed and preferentially in flower. MeJA treatment enhanced the accumulation of PnSEI mRNA expression level in leaves, while there is no obvious enhancement of PnSE2 in same condition. Results indicated that the gene expressions of PnSE1 and PnSE2 were differently transcribed in four organs, and two PnSEs differently responded to MeJA stimuli. It was strongly suggested that PnSEs play different roles in secondary metabolite biosynthesis in P. notoginseng. PnSE1 might be involved in triterpenoid biosynthesis and PnSE2 might be involved in phytosterol biosynthesis.

Stimulation of trans-resveratrol biosynthesis in Vitis vinifera cv. Kyoho cell suspension cultures by 2, 3-dihydroxypropyl jasmonate elicitation

Background: Plant cell suspension culture of Vitis vinifera is a promising technology for investigating different factors that are able to induce and/or modify stilbenes biosynthesis. Jasmonates have been reported to play an important role in a signal transduction pathway that regulates defence responses as well as the production of secondary metabolites. In this study, 2, 3-dihydroxypropyl jasmonate (DHPJA) was used to investigate its effect on stimulating trans-resveratrol (t-R) accumulation and the plant defence responses in Vitis vinifera cv. Kyoho cell suspension cultures for the first time. Results: It demonstrated that DHPJA had superior effects on stilbenoids accumulation over methyl jasmonate (MeJA). The optimal condition was 150 uM DHPJA added on day 15 of cultivation period, with the highest level of t-R accumulation which was increased 1.8-fold and 1.3-fold compared with the control and 150 uM MeJA respectively. DHPJA induced stronger plant defence responses, including oxidative burst and activation of L-phenylalanine ammonia lyase (PAL) than MeJA. H2O2 generation induced by DHPJA played a significant role in enhancing t-R accumulation. Adding a specific inhibitor of H2O2 signalling pathway inhibited DHPJA-induced t-R accumulation, but had no effects on DHPJA-induced other metabolites accumulation, which resulted in regulations of product diversity. Conclusions: This study demonstrated that DHPJA was an efficient elicitor to enhance t-R accumulation by activating stronger oxidative burst, and H2O2 signalling pathway could regulate product diversity in DHPJA-induced V. vinifera cv. Kyoho cell suspension cultures.

Induction of the expression of defence genes in Carica papaya fruit by methyl jasmonate and low temperature treatments

The defence mechanisms that are activated by methyl jasmonate (MJ) in fruits are not well understood. In this work, we studied the expression of defence genes in papaya fruit that are induced by the exposure to MJ and/or low temperatures. The papaya fruits ‘Maradol’ were randomly divided into two groups: one group was the untreated control and the other was treated with 10-4 M of MJ. Half of the fruits from each of the two groups were stored after treatment for 5 days at 5ºC and 2 days at 20ºC. We studied the expression levels of the pdf1.1 and pdf1.2 genes by amplification from expression libraries created from the pulp and skin tissues of the papaya fruit. As a reference, the mRNA level of the 18s ribosomal gene was used. In the skin tissue, the expression levels of the pdf1.1 and pdf1.2 genes were higher immediately after MJ treatment compared to the control. Furthermore, the expression of pdf1.2 remained high after MJ treatment and subsequent storage compared to the control. It was therefore concluded that the activation of the pdf1.1 and pdf1.2 genes forms part of the molecular defence mechanism in fruits that is activated by exposure to MJ. To our knowledge, this is the first study that analyzes the gene expression in papaya fruit that is induced by the exogenous application of methyl jasmonate and cold treatment.