Involvement of Pyochelin and Pyoverdin in Suppression of Pythium-Induced Damping-Off of Tomato by Pseudomonas aeruginosa 7NSK2

The plant growth-promoting rhizobacterium Pseudomonas aeruginosa 7NSK2 produces three siderophores when iron is limited: the yellow-green fluorescent pyoverdin, the salicylate derivative pyochelin, and salicylic acid. This Pseudomonas strain was shown to be an efficient antagonist of Pythium-induced damping-off. The role of pyoverdin and pyochelin in the suppression of Pythium splendens was investigated by using various siderophore-deficient mutants derived from P. aeruginosa 7NSK2 in a bioassay with tomato (Lycopersicon esculentum). To provide more insight into the role of pyochelin in antagonism, mutant KMPCH, deficient in the production of pyoverdin and pyochelin, was complemented for pyochelin production. The complementing clone was further characterized by subcloning and transposon mutagenesis and used to generate a pyochelin-negative, pyoverdin-positive mutant by marker exchange. All mutants were able to reduce Pythium-induced preemergence damping-off to some extent. Production of either pyoverdin or pyochelin proved to be necessary to achieve wild-type levels of protection against Pythium-induced postemergence damping-off. Mutant KMPCH inhibited P. splendens but was less active than the parental strain. This residual protection could be due to the production of salicylic acid. Since pyoverdin and pyochelin are both siderophores, siderophore-mediated iron competition could explain the observed antagonism and the apparent interchangeability of the two compounds. We cannot, however, exclude the possibility that both siderophores act in an indirect way.     

Isolation and characterization of Burkholderia cenocepacia mutants deficient in pyochelin production: pyochelin biosynthesis is sensitive to sulfur availability

The opportunistic pathogen Burkholderia cenocepacia produces the yellow-green fluorescent siderophore, pyochelin. To isolate mutants which do not produce this siderophore, we mutagenized B. cenocepacia with the transposon mini-Tn5Tp. Two nonfluorescent mutants were identified which were unable to produce pyochelin. In both mutants, the transposon had integrated into a gene encoding an orthologue of CysW, a component of the sulfate/thiosulfate transporter. The cysW gene was located within a putative operon encoding other components of the transporter and a polypeptide exhibiting high homology to the LysR-type regulators CysB and Cbl. Sulfate uptake assays confirmed that both mutants were defective in sulfate transport. Growth in the presence of cysteine, but not methionine, restored the ability of the mutants to produce pyochelin, suggesting that the failure to produce the siderophore was the result of a depleted intracellular pool of cysteine, a biosynthetic precursor of pyochelin. Consistent with this, the wild-type strain did not produce pyochelin when grown in the presence of lower concentrations of sulfate that still supported efficient growth. We also showed that whereas methionine and certain organosulfonates can serve as sole sulfur sources for this bacterium, they do not facilitate pyochelin biosynthesis. These observations suggest that, under conditions of sulfur depletion, cysteine cannot be spared for production of pyochelin even under iron starvation conditions.     

Heat stress phenotypes of Arabidopsis mutants implicate multiple signaling pathways in the acquisition of thermotolerance

To investigate the importance of different processes to heat stress tolerance, 45 Arabidopsis (Arabidopsis thaliana) mutants and one transgenic line were tested for basal and acquired thermotolerance at different stages of growth. Plants tested were defective in signaling pathways (abscisic acid, salicylic acid, ethylene, and oxidative burst signaling) and in reactive oxygen metabolism (ascorbic acid or glutathione production, catalase) or had previously been found to have temperature-related phenotypes (e.g. fatty acid desaturase mutants, uvh6). Mutants were assessed for thermotolerance defects in seed germination, hypocotyl elongation, root growth, and seedling survival. To assess oxidative damage and alterations in the heat shock response, thiobarbituric acid reactive substances, heat shock protein 101, and small heat shock protein levels were determined. Fifteen mutants showed significant phenotypes. Abscisic acid (ABA) signaling mutants (abi1 and abi2) and the UV-sensitive mutant, uvh6, showed the strongest defects in acquired thermotolerance of root growth and seedling survival. Mutations in nicotinamide adenine dinucleotide phosphate oxidase homolog genes (atrbohB and D), ABA biosynthesis mutants (aba1, aba2, and aba3), and NahG transgenic lines (salicylic acid deficient) showed weaker defects. Ethylene signaling mutants (ein2 and etr1) and reactive oxygen metabolism mutants (vtc1, vtc2, npq1, and cad2) were more defective in basal than acquired thermotolerance, especially under high light. All mutants accumulated wild-type levels of heat shock protein 101 and small heat shock proteins. These data indicate that, separate from heat shock protein induction, ABA, active oxygen species, and salicylic acid pathways are involved in acquired thermotolerance and that UVH6 plays a significant role in temperature responses in addition to its role in UV stress.     

Ethylene and salicylic acid control glutathione biosynthesis in ozone‐exposed Arabidopsis thaliana

Ozone produces reactive oxygen species and induces the synthesis of phytohormones, including ethylene and salicylic acid. These phytohormones act as signal molecules that enhance cell death in response to ozone exposure. However, some studies have shown that ethylene and salicylic acid can instead decrease the magnitude of ozone‐induced cell death. Therefore, we studied the defensive roles of ethylene and salicylic acid against ozone. Unlike the wild‐type, Col‐0, Arabidopsis mutants deficient in ethylene signaling (ein2) or salicylic acid biosynthesis (sid2) generated high levels of superoxide and exhibited visible leaf injury, indicating that ethylene and salicylic acid can reduce ozone damage. Macroarray analysis suggested that the ethylene and salicylic acid defects influenced glutathione (GSH) metabolism. Increases in the reduced form of GSH occurred in Col‐0 6 h after ozone exposure, but little GSH was detected in ein2 and sid2 mutants, suggesting that GSH levels were affected by ethylene or salicylic acid signaling. We performed gene expression analysis by real‐time polymerase chain reaction using genes involved in GSH metabolism. Induction of γ‐glutamylcysteine synthetase (GSH1), glutathione synthetase (GSH2), and glutathione reductase 1 (GR1) expression occurred normally in Col‐0, but at much lower levels in ein2 and sid2. Enzymatic activities of GSH1 and GSH2 in ein2 and sid2 were significantly lower than in Col‐0. Moreover, ozone‐induced leaf damage observed in ein2 and sid2 was mitigated by artificial elevation of GSH content. Our results suggest that ethylene and salicylic acid protect against ozone‐induced leaf injury by increasing de novo biosynthesis of GSH.     

Essential PchG-dependent reduction in pyochelin biosynthesis of Pseudomonas aeruginosa

The biosynthetic genes pchDCBA and pchEF, which are known to be required for the formation of the siderophore pyochelin and its precursors salicylate and dihydroaeruginoate (Dha), are clustered with the pchR regulatory gene on the chromosome of Pseudomonas aeruginosa. The 4.6-kb region located downstream of the pchEF genes was found to contain three additional, contiguous genes, pchG, pchH, and pchI, probably forming a pchEFGHI operon. The deduced amino acid sequences of PchH and PchI are similar to those of ATP binding cassette transport proteins with an export function. PchG is a homolog of the Yersinia pestis and Y. enterocolitica proteins YbtU and Irp3, which are involved in the biosynthesis of yersiniabactin. A null mutation in pchG abolished pyochelin formation, whereas mutations in pchH and pchI did not affect the amounts of salicylate, Dha, and pyochelin produced. The pyochelin biosynthetic genes were expressed from a vector promoter, uncoupling them from Fur-mediated repression by iron and PchR-dependent induction by pyochelin. In a P. aeruginosa mutant lacking the entire pyochelin biosynthetic gene cluster, the expressed pchDCBA and pchEFG genes were sufficient for salicylate, Dha, and pyochelin production. Pyochelin formation was also obtained in the heterologous host Escherichia coli expressing pchDCBA and pchEFG together with the E. coli entD gene, which provides a phosphopantetheinyl transferase necessary for PchE and PchF activation. The PchG protein was purified and used in combination with PchD and phosphopantetheinylated PchE and PchF in vitro to produce pyochelin from salicylate, L-cysteine, ATP, NADPH, and S-adenosylmethionine. Based on this assay, a reductase function was attributed to PchG. In summary, this study completes the identification of the biosynthetic genes required for pyochelin formation from chorismate in P. aeruginosa.     

The role of phytohormone signaling in ozone-induced cell death in plants

Ozone is the main photochemical oxidant that causes leaf damage in many plant species, and can thereby significantly decrease the productivity of crops and forests. When ozone is incorporated into plants, it produces reactive oxygen species (ROS), such as superoxide radicals and hydrogen peroxide. These ROS induce the synthesis of several plant hormones, such as ethylene, salicylic acid, and jasmonic acid. These phytohormones are required for plant growth, development, and defense responses, and regulate the extent of leaf injury in ozone-fumigated plants. Recently, responses to ozone have been studied using genetically modified plants and mutants with altered hormone levels or signaling pathways. These researches have clarified the roles of phytohormones and the complexity of their signaling pathways. The present paper reviews the biosynthesis of the phytohormones ethylene, salicylic acid, and jasmonic acid, their roles in plant responses to ozone, and multiple interactions between these phytohormones in ozone-exposed plants.Key words: cross-talk, ethylene, jasmonic acid, ozone, phytohormones, programmed cell death, salicylic acid, signaling pathways     

Environmental factors modulating antibiotic and siderophore biosynthesis by Pseudomonas fluorescens biocontrol strains.

Understanding the environmental factors that regulate the biosynthesis of antimicrobial compounds by disease-suppressive strains of Pseudomonas fluorescens is an essential step toward improving the level and reliability of their biocontrol activity. We used liquid culture assays to identify several minerals and carbon sources which had a differential influence on the production of the antibiotics 2,4-diacetylphloroglucinol (PHL), pyoluteorin (PLT), and pyrrolnitrin and the siderophores salicylic acid and pyochelin by the model strain CHA0, which was isolated from a natural disease-suppressive soil in Switzerland. Production of PHL was stimulated by Zn2+, NH4Mo2+, and glucose; the precursor compound mono-acetylphloroglucinol was stimulated by the same factors as PHL. Production of PLT was stimulated by Zn2+, Co2+, and glycerol but was repressed by glucose. Pyrrolnitrin production was increased by fructose, mannitol, and a mixture of Zn2+ and NH4Mo2+. Pyochelin production was increased by Co2+, fructose, mannitol, and glucose. Interestingly, production of its precursor salicylic acid was increased by different factors, i.e., NH4Mo2+, glycerol, and glucose. The mixture of Zn2+ and NH4Mo2+ with fructose, mannitol, or glycerol further enhanced the production of PHL and PLT compared with either the minerals or the carbon sources used alone, but it did not improve siderophore production. Extending fermentation time from 2 to 5 days increased the accumulation of PLT, pyrrolnitrin, and pyochelin but not of PHL. When findings with CHA0 were extended to an ecologically and genetically diverse collection of 41 P. fluorescens biocontrol strains, the effect of certain factors was strain dependent, while others had a general effect. Stimulation of PHL by Zn2+ and glucose was strain dependent, whereas PLT production by all strains that can produce this compound was stimulated by Zn2+ and transiently repressed by glucose. Inorganic phosphate reduced PHL production by CHA0 and seven other strains tested but to various degrees. Production of PLT but not pyrrolnitrin by CHA0 was also reduced by 100 mM phosphate. The use of 1/10-strength nutrient broth-yeast extract, compared with standard nutrient broth-yeast extract, amended with glucose and/or glycerol resulted in dramatically increased accumulations of PHL (but not PLT), pyochelin, and salicylic acid, indicating that the ratio of carbon source to nutrient concentration played a key role in the metabolic flow. The results of this study (i) provide insight into the biosynthetic regulation of antimicrobial compounds, (ii) limit the number of factors for intensive study in situ, and (iii) indicate factors that can be manipulated to improve bacterial inoculants.     

PchR-box recognition by the AraC-type regulator PchR of Pseudomonas aeruginosa requires the siderophore pyochelin as an effector

Under iron limitation, the opportunistic human pathogen Pseudomonas aeruginosa produces the siderophore pyochelin. When secreted into the extracellular environment, pyochelin complexes ferric ions and delivers them, via the outer membrane receptor FptA, to the bacterial cytoplasm. Extracellular pyochelin also acts as a signalling molecule, inducing the expression of pyochelin biosynthesis and uptake genes by a mechanism involving the AraC-type regulator PchR. We have identified a 32 bp conserved sequence element (PchR-box) in promoter regions of pyochelin-controlled genes and we show that the PchR-box in the pchR-pchDCBA intergenic region is essential for the induction of the pyochelin biosynthetic operon pchDCBA and the repression of the divergently transcribed pchR gene. PchR was purified as a fusion with maltose-binding protein (MBP). Mobility shift assays demonstrated specific binding of MBP-PchR to the PchR-box in the presence, but not in the absence of pyochelin and iron. PchR-box mutations that interfered with pyochelin-dependent regulation in vivo, also affected pyochelin-dependent PchR-box recognition in vitro. We conclude that pyochelin, probably in its iron-loaded state, is the intracellular effector required for PchR-mediated regulation. The fact that extracellular pyochelin triggers this regulation suggests that the siderophore can enter the cytoplasm.     

Catecholate Siderophores Protect Bacteria from Pyochelin Toxicity

Background

Bacteria produce small molecule iron chelators, known as siderophores, to facilitate the acquisition of iron from the environment. The synthesis of more than one siderophore and the production of multiple siderophore uptake systems by a single bacterial species are common place. The selective advantages conferred by the multiplicity of siderophore synthesis remains poorly understood. However, there is growing evidence suggesting that siderophores may have other physiological roles besides their involvement in iron acquisition.

Methods and Principal Findings

Here we provide the first report that pyochelin displays antibiotic activity against some bacterial strains. Observation of differential sensitivity to pyochelin against a panel of bacteria provided the first indications that catecholate siderophores, produced by some bacteria, may have roles other than iron acquisition. A pattern emerged where only those strains able to make catecholate-type siderophores were resistant to pyochelin. We were able to associate pyochelin resistance to catecholate production by showing that pyochelin-resistant Escherichia coli became sensitive when biosynthesis of its catecholate siderophore enterobactin was impaired. As expected, supplementation with enterobactin conferred pyochelin resistance to the entE mutant. We observed that pyochelin-induced growth inhibition was independent of iron availability and was prevented by addition of the reducing agent ascorbic acid or by anaerobic incubation. Addition of pyochelin to E. coli increased the levels of reactive oxygen species (ROS) while addition of ascorbic acid or enterobactin reduced them. In contrast, addition of the carboxylate-type siderophore, citrate, did not prevent pyochelin-induced ROS increases and their associated toxicity.

Conclusions

We have shown that the catecholate siderophore enterobactin protects E. coli against the toxic effects of pyochelin by reducing ROS. Thus, it appears that catecholate siderophores can behave as protectors of oxidative stress. These results support the idea that siderophores can have physiological roles aside from those in iron acquisition.     

水杨酸对细胞培养生产紫杉烷的影响

研究了水杨酸对中国红豆杉细胞培养生产紫杉烷的影响。结果表明 ,适宜浓度的水杨酸对不同的紫杉烷的合成均有明显的促进作用     

Pleiotropic changes in Arabidopsis <Emphasis Type="Italic">f5h</Emphasis> and <Emphasis Type="Italic">sct</Emphasis> mutants revealed by large-scale gene expression and metabolite analysis

Hydrocinnamic acid esters, lignin, flavonoids, glucosinolates, and salicylic acid protect plants against UV exposure, oxidative stress, diseases, and herbivores. Through the phenylpropanoid pathway, certain Brassicaceae family members, including Arabidopsis thaliana and Brassica napus, accumulate large amounts of the anti-nutritive sinapoylcholine (sinapine) in the seed. We successfully down-regulated activities of key enzymes in the pathway including F5H and SCT and achieved reduction of sinapine and lignin in B. napus seeds. Despite this success, it was unclear how multiple agronomic traits were affected in the transgenic plants. Here, we report altered large-scale gene expression of new alleles of f5h and sct mutants of A. thaliana and resultant accumulation of sinapoylglucose, disinapoylglucose, quercetin-3-O-rhamnoside, salicylic acid glucoside, and total indolyl glucosinolates in the two mutants. Expression of several flowering genes was altered in these mutants when grown under drought and NaCl treatments. Furthermore, both mutants were more susceptible to fungal infection than the wild type. Microarray experiments identified distinctive spatial and temporal expression patterns of gene clusters involved in silique/seed developmental processes and metabolite biosynthesis in these mutants. Taken together, these findings suggest that both f5h and sct mutants exhibit major differences in accumulation of diverse metabolites in the seed and profound changes in global large-scale gene expression, resulting in differential pleiotropic responses to environmental cues.     

Characterization of Arabidopsis mur3 mutations that result in constitutive activation of defence in petioles, but not leaves

A screen was established for mutants in which the plant defence response is de-repressed. The pathogen-inducible isochorismate synthase (ICS1) promoter was fused to firefly luciferase (luc) and a homozygous transgenic line generated in which the ICS1:luc fusion is co-regulated with ICS1. This line was mutagenized and M(2) seedlings screened for constitutive ICS1:luc expression (cie). The cie mutants fall into distinct phenotypic classes based on tissue-specific localization of luciferase activity. One mutant, cie1, that shows constitutive luciferase activity specifically in petioles, was chosen for further analysis. In addition to ICS1, PR and other defence-related genes are constitutively expressed in cie1 plants. The cie1 mutant is also characterized by an increased production of conjugated salicylic acid and reactive oxygen intermediates, as well as spontaneous lesion formation, all confined to petiole tissue. Significantly, defences activated in cie1 are sufficient to prevent infection by a virulent isolate of Hyaloperonospora parasitica, and this enhanced resistance response protects petiole tissue alone. Furthermore, cie1-mediated resistance, along with PR gene expression, is abolished in a sid2-1 mutant background, consistent with a requirement for salicylic acid. A positional cloning approach was used to identify cie1, which carries two point mutations in a gene required for cell wall biosynthesis and actin organization, MUR3. A mur3 knockout mutant also resists infection by H. parasitica in its petioles and this phenotype is complemented by transformation with wild-type MUR3. We propose that perturbed cell wall biosynthesis may activate plant defence and provide a rationale for the cie1 and the mur3 knockout phenotypes.     

Environmental Factors Modulating Antibiotic and Siderophore Biosynthesis by Pseudomonas fluorescens Biocontrol Strains

Understanding the environmental factors that regulate the biosynthesis of antimicrobial compounds by disease-suppressive strains of Pseudomonas fluorescens is an essential step toward improving the level and reliability of their biocontrol activity. We used liquid culture assays to identify several minerals and carbon sources which had a differential influence on the production of the antibiotics 2,4-diacetylphloroglucinol (PHL), pyoluteorin (PLT), and pyrrolnitrin and the siderophores salicylic acid and pyochelin by the model strain CHA0, which was isolated from a natural disease-suppressive soil in Switzerland. Production of PHL was stimulated by Zn²⁺, NH₄Mo²⁺, and glucose; the precursor compound mono-acetylphloroglucinol was stimulated by the same factors as PHL. Production of PLT was stimulated by Zn²⁺, Co²⁺, and glycerol but was repressed by glucose. Pyrrolnitrin production was increased by fructose, mannitol, and a mixture of Zn²⁺ and NH₄Mo²⁺. Pyochelin production was increased by Co²⁺, fructose, mannitol, and glucose. Interestingly, production of its precursor salicylic acid was increased by different factors, i.e., NH₄Mo²⁺, glycerol, and glucose. The mixture of Zn²⁺ and NH₄Mo²⁺ with fructose, mannitol, or glycerol further enhanced the production of PHL and PLT compared with either the minerals or the carbon sources used alone, but it did not improve siderophore production. Extending fermentation time from 2 to 5 days increased the accumulation of PLT, pyrrolnitrin, and pyochelin but not of PHL. When findings with CHA0 were extended to an ecologically and genetically diverse collection of 41 P. fluorescens biocontrol strains, the effect of certain factors was strain dependent, while others had a general effect. Stimulation of PHL by Zn²⁺ and glucose was strain dependent, whereas PLT production by all strains that can produce this compound was stimulated by Zn²⁺ and transiently repressed by glucose. Inorganic phosphate reduced PHL production by CHA0 and seven other strains tested but to various degrees. Production of PLT but not pyrrolnitrin by CHA0 was also reduced by 100 mM phosphate. The use of 1/10-strength nutrient broth-yeast extract, compared with standard nutrient broth-yeast extract, amended with glucose and/or glycerol resulted in dramatically increased accumulations of PHL (but not PLT), pyochelin, and salicylic acid, indicating that the ratio of carbon source to nutrient concentration played a key role in the metabolic flow. The results of this study (i) provide insight into the biosynthetic regulation of antimicrobial compounds, (ii) limit the number of factors for intensive study in situ, and (iii) indicate factors that can be manipulated to improve bacterial inoculants.     

Ferric uptake regulator (Fur) mutants of Pseudomonas aeruginosa demonstrate defective siderophore-mediated iron uptake, altered aerobic growth, and decreased superoxide dismutase and catalase activities.

Pseudomonas aeruginosa is considered a strict aerobe that possesses several enzymes important in the disposal of toxic oxygen reduction products including iron- and manganese-cofactored superoxide dismutase and catalase. At present, the nature of the regulation of these enzymes in P. aeruginosa Is not understood. To address these issues, we used two mutants called A4 and C6 which express altered Fur (named for ferric uptake regulation) proteins and constitutively produce the siderophores pyochelin and pyoverdin. Both mutants required a significant lag phase prior to log-phase aerobic growth, but this lag was not as apparent when the organisms were grown under microaerobic conditions. The addition of iron salts to mutant A4 and, to a greater extent, C6 cultures allowed for an increased growth rate under both conditions relative to that of bacteria without added iron. Increased manganese superoxide dismutase (Mn-SOD) and decreased catalase activities were also apparent in the mutants, although the second catalase, KatB, was detected in cell extracts of each fur mutant. Iron deprivation by the addition of the iron chelator 2,2'-dipyridyl to wild-type bacteria produced an increase in Mn-SOD activity and a decrease in total catalase activity, similar to the fur mutant phenotype. Purified wild-type Fur bound more avidly than mutant Fur to a PCR product containing two palindromic 19-bp "iron box" regions controlling expression of an operon containing the sodA gene that encodes Mn-SOD. All mutants were defective in both ferripyochelin- and ferripyoverdin-mediated iron uptake. Two mutants of strain PAO1, defective in pyoverdin but not pyochelin biosynthesis, produced increased Mn-SOD activity. Sensitivity to both the redox-cycling agent paraquat and hydrogen peroxide was greater in each mutant than in the wild-type strain. In summary, the results indicate that mutations in the P. aeruginosa fur locus affect aerobic growth and SOD and catalase activities in P. aeruginosa. We postulate that reduced siderophore-mediated iron uptake, especially that by pyoverdin, may be one possible mechanism contributing to such effect.     

Tn5 insertion mutants of Pseudomonas aeruginosa deficient in surface expression of ferripyochelin-binding protein.

Transposon (Tn5) insertion mutants were isolated in Pseudomonas aeruginosa PAO. These mutants were screened for expression of the ferripyochelin-binding protein with monoclonal antibody in a whole-cell immunoblot assay. Fourteen mutants were identified which did not express ferripyochelin-binding protein on the cell surface. These mutants did not take up 59Fe-labeled pyochelin and grew slowly in the presence of iron chelators.     

水杨酸在紫杉醇生物合成中诱导作用的研究

研究了水杨酸对红豆杉细胞培养中紫杉烷合成的影响。在适宜浓度的水杨酸诱导下,紫杉醇(Taxol)的产量提高了近3倍,同时10去乙酰基巴卡亭Ⅲ(10-DAB)与巴卡亭Ⅲ(Baccatin Ⅲ)相应上升。通过对紫杉醇合成代谢途径的动力学分析,初步推断水杨酸的加入提高了10-DAB合成速率。并通过水杨酸和硝酸银的配伍诱导,实现了诱导子之间的协同作用,获得了39 mg/L的紫杉醇含量,比两个诱导子单独作用时的最高含量之和还高出50%。     

Recent breakthroughs in the study of salicylic acid biosynthesis

Salicylic acid is an important regulator of induced plant resistance to pathogens. Consequently, the biosynthesis of salicylic acid and its regulation has received a lot of attention. Salicylic acid can be made from phenylalanine via cinnamic and benzoic acid. Recently, genetic studies in Arabidopsis have shown that salicylic acid is made in the chloroplast from isochorismate, a pathway that is known to operate in prokaryotes.     

代谢调节剂对紫杉醇和Taxuyunnanine C生物合成的调控作用

研究了诱导子、前体和抑制剂对东北红豆杉生产紫杉醇和taxuyunnanine C的影响。结果表明,诱导子在第12d添加,前体和抑制剂在第15d添加能有效地提高紫杉醇和taxuyunnanine C的含量。水杨酸与氯化氯胆碱的交互作用对紫杉醇的合成有很大影响,水杨酸与赤霉酸的交互作用对taxuyunnanine C的合成有很大影响。