Isochorismate Synthase

We have recently shown that an Arabidopsis thaliana double mutant of type III phosphatidylinositol-4-kinases (PI4Ks), pi4kβ1β2, constitutively accumulated a high level of salicylic acid (SA). By crossing this pi4kβ1β2 double mutant with mutants impaired in SA synthesis (such as sid2 impaired in isochorismate synthase) or transduction, we demonstrated that the high SA level was responsible for the dwarfism phenotype of the double mutant. Here we aimed at distinguishing between the SA-dependent and -independent effects triggered by the deficiency in PI4Kβ1 and PI4Kβ2. To achieve this, the sid2pi4kβ1β2 triple mutant was a tool of choice. High-throughput analyses of phytohormones were performed on this mutant together with pi4kβ1β2 and sid2 mutants and wild-type plants. Responses to pathogens, namely Hyaloperonospora arabidopsidis, Pseudomonas syringae and Botrytis cinerea, but as well to the non-host fungus Blumeria graminis, were also determined. Callose accumulation was monitored in response to flagellin. We show here the prominent role of high SA levels in influencing the concentration of many other tested phytohormones, including abscisic acid and its derivatives, the Aspartateconjugated form of indole-3-acetic acid and some cytokinins such as cis-zeatin. We show that the increased resistance of pi4kβ1β2 plants to the host pathogens Hyaloperonospora arabidopsidis, Pseudomonas syringae pv. tomato DC3000 and Bothrytis cinerea is dependent on accumulation of high SA level. In contrast, accumulation of callose in pi4kβ1β2 after flagellin treatment was independent of SA. Concerning the response to Blumeria graminis, both callose accumulation and fungal penetration were enhanced in the pi4kβ1β2 double mutant compared to wild-type plants. Both of these processes occurred in a SA-independent manner. Our data extensively illustrate the influence of SA on other phytohormone levels. The sid2pi4kβ1β2 triple mutant allowed to uncover the role of PI4Kβ1/β2 per se, thus showing the importance of these enzymes in plant defence responses.

The isochorismate synthase DhbC from Bacillus anthracis is essential for the biosynthesis of the siderophore bacillibactin by this pathogenic bacterium. The structure of the selenomethionine-substituted protein was determined to 2.4 Å resolution using single-wavelength anomalous diffraction. B. anthracis DhbC bears the strongest resemblance to the Escherichia coli isochorismate synthase EntC, which is involved in the biosynthesis of another siderophore, namely enterobactin. Both proteins adopt the characteristic fold of other chorismateutilizing enzymes, which are involved in the biosynthesis of various products, including siderophores, menaquinone and tryptophan. The conservation of the active-site residues, as well as their spatial arrangement, suggests that these enzymes share a common Mg 2+-dependent catalytic mechanism.

Background and Aims We have recently shown that an Arabidopsis thaliana double mutant of type III phosphatidylinositol-4-kinases (PI4Ks), pi4kβ1β2, constitutively accumulated a high level of salicylic acid (SA). By crossing this pi4kβ1β2 double mutant with mutants impaired in SA synthesis (such as sid2 impaired in isochorismate synthase) or transduction, we demonstrated that the high SA level was responsible for the dwarfism phenotype of the double mutant. Here we aimed to distinguish between the SA-dependent and SA-independent effects triggered by the deficiency in PI4Kβ1 and PI4Kβ2. Methods To achieve this we used the sid2pi4kβ1β2 triple mutant. High-throughput analyses of phytohormones were performed on this mutant together with pi4kβ1β2 and sid2 mutants and wild-type plants. Responses to pathogens, namely Hyaloperonospora arabidopsidis, Pseudomonas syringae and Botrytis cinerea, and also to the non-host fungus Blumeria graminis, were also determined. Callose accumulation was mon...

Background and Aims We have recently shown that an Arabidopsis thaliana double mutant of type III phosphatidylinositol-4-kinases (PI4Ks), pi4kβ1β2, constitutively accumulated a high level of salicylic acid (SA). By crossing this pi4kβ1β2 double mutant with mutants impaired in SA synthesis (such as sid2 impaired in isochorismate synthase) or transduction, we demonstrated that the high SA level was responsible for the dwarfism phenotype of the double mutant. Here we aimed to distinguish between the SA-dependent and SA-independent effects triggered by the deficiency in PI4Kβ1 and PI4Kβ2. Methods To achieve this we used the sid2pi4kβ1β2 triple mutant. High-throughput analyses of phytohormones were performed on this mutant together with pi4kβ1β2 and sid2 mutants and wild-type plants. Responses to pathogens, namely Hyaloperonospora arabidopsidis, Pseudomonas syringae and Botrytis cinerea, and also to the non-host fungus Blumeria graminis, were also determined. Callose accumulation was mon...

Background: pABA biosynthesis is a potential target for antifolate drugs. Results: Rubreserine inhibits GAT-ADCS, an enzyme involved in pABA biosynthesis, and decreases the folate content in Arabidopsis and Toxoplasma. Conclusion: Specific inhibition of pABA synthesis induces growth limitation of plants and apicomplexan parasites. Significance: GAT-ADCS is a valuable target in eukaryotes, and rubreserine is a novel scaffold for anti-parasitic drugs. Glutamine amidotransferase/aminodeoxychorismate synthase (GAT-ADCS) is a bifunctional enzyme involved in the synthesis of p-aminobenzoate, a central component part of folate cofactors. GAT-ADCS is found in eukaryotic organisms autonomous for folate biosynthesis, such as plants or parasites of the phylum Apicomplexa. Based on an automated screening to search for new inhibitors of folate biosynthesis, we found that rubreserine was able to inhibit the glutamine amidotransferase activity of the plant GAT-ADCS with an apparent IC 50 of about 8 M. The growth rates of Arabidopsis thaliana, Toxoplasma gondii, and Plasmodium falciparum were inhibited by rubreserine with respective IC 50 values of 65, 20, and 1 M. The correlation between folate biosynthesis and growth inhibition was studied with Arabidopsis and Toxoplasma. In both organisms, the folate content was decreased by 40-50% in the presence of rubreserine. In both organisms, the addition of p-aminobenzoate or 5-formyltetrahydrofolate in the external medium restored the growth for inhibitor concentrations up to the IC 50 value, indicating that, within this range of concentrations, rubreserine was specific for folate biosynthesis. Rubreserine appeared to be more efficient than sulfonamides, antifolate drugs known to inhibit the invasion and proliferation of T. gon-dii in human fibroblasts. Altogether, these results validate the use of the bifunctional GAT-ADCS as an efficient drug target in eukaryotic cells and indicate that the chemical structure of rubreserine presents interesting anti-parasitic (toxoplasmosis, malaria) potential. Folates are a family of cofactors that are essential for cellular one-carbon (C1) transfer reactions. They are involved in several important metabolic pathways, such as the synthesis of nucleotides and the methylation cycle (1-3). Folate biosynthesis can be divided into three branches (Fig. 1A) as follows: the first one is for the pterin ring synthesis; the second one is for the pABA 5 synthesis, and the third one is for the assembly of these two precursors plus glutamates to form the backbone of folate derivatives (4-6). Blocking folate biosynthesis or turnover leads to the arrest of cell division and eventually to cell death. Antifolate drugs have been developed to exploit this feature in therapies against cancer cells and microbial or parasitic infections. Biosynthesis of folate is mainly inhibited by two groups of compounds, i.e. inhibitors of dihydropteroate synthase (DHPS) and inhibitors of dihydrofolate reductase (DHFR). Inhibitors of DHFR are commonly used as therapeutic agents against cancer (7), whereas a combination of these two types of inhibitors are * This work was supported in part the Région Rhône-Alpes (Cluster 9, "Plantacter"). □ S This article contains supplemental Fig. 1. 1 Ph.D. fellowship was supported by the Région Rhône-Alpes (Cluster 9, "Plantacter").

Background: pABA biosynthesis is a potential target for antifolate drugs. Results: Rubreserine inhibits GAT-ADCS, an enzyme involved in pABA biosynthesis, and decreases the folate content in Arabidopsis and Toxoplasma. Conclusion: Specific inhibition of pABA synthesis induces growth limitation of plants and apicomplexan parasites. Significance: GAT-ADCS is a valuable target in eukaryotes, and rubreserine is a novel scaffold for anti-parasitic drugs. Glutamine amidotransferase/aminodeoxychorismate synthase (GAT-ADCS) is a bifunctional enzyme involved in the synthesis of p-aminobenzoate, a central component part of folate cofactors. GAT-ADCS is found in eukaryotic organisms autonomous for folate biosynthesis, such as plants or parasites of the phylum Apicomplexa. Based on an automated screening to search for new inhibitors of folate biosynthesis, we found that rubreserine was able to inhibit the glutamine amidotransferase activity of the plant GAT-ADCS with an apparent IC 50 of about 8 M. The growth rates of Arabidopsis thaliana, Toxoplasma gondii, and Plasmodium falciparum were inhibited by rubreserine with respective IC 50 values of 65, 20, and 1 M. The correlation between folate biosynthesis and growth inhibition was studied with Arabidopsis and Toxoplasma. In both organisms, the folate content was decreased by 40-50% in the presence of rubreserine. In both organisms, the addition of p-aminobenzoate or 5-formyltetrahydrofolate in the external medium restored the growth for inhibitor concentrations up to the IC 50 value, indicating that, within this range of concentrations, rubreserine was specific for folate biosynthesis. Rubreserine appeared to be more efficient than sulfonamides, antifolate drugs known to inhibit the invasion and proliferation of T. gon-dii in human fibroblasts. Altogether, these results validate the use of the bifunctional GAT-ADCS as an efficient drug target in eukaryotic cells and indicate that the chemical structure of rubreserine presents interesting anti-parasitic (toxoplasmosis, malaria) potential. Folates are a family of cofactors that are essential for cellular one-carbon (C1) transfer reactions. They are involved in several important metabolic pathways, such as the synthesis of nucleotides and the methylation cycle (1-3). Folate biosynthesis can be divided into three branches (Fig. 1A) as follows: the first one is for the pterin ring synthesis; the second one is for the pABA 5 synthesis, and the third one is for the assembly of these two precursors plus glutamates to form the backbone of folate derivatives (4-6). Blocking folate biosynthesis or turnover leads to the arrest of cell division and eventually to cell death. Antifolate drugs have been developed to exploit this feature in therapies against cancer cells and microbial or parasitic infections. Biosynthesis of folate is mainly inhibited by two groups of compounds, i.e. inhibitors of dihydropteroate synthase (DHPS) and inhibitors of dihydrofolate reductase (DHFR). Inhibitors of DHFR are commonly used as therapeutic agents against cancer (7), whereas a combination of these two types of inhibitors are * This work was supported in part the Région Rhône-Alpes (Cluster 9, "Plantacter"). □ S This article contains supplemental Fig. 1. 1 Ph.D. fellowship was supported by the Région Rhône-Alpes (Cluster 9, "Plantacter").

Safflower (Carthamus tinctorius L.) serves as a reference dicot for investigation of defence mechanisms in Asteraceae due to abundant secondary metabolites and high resistance/tolerance to environmental stresses. In plants, phenylpropanoid and flavonoid pathways are considered as two central defence signalling cascades in stress conditions. Here, we describe the isolation of two major genes in these pathways, CtPAL (phenylalanine ammonia-lyase) and CtCHS (chalcone synthase) in safflower along with monitoring their expression profiles in different stress circumstances. The aa (amino acid) sequence of isolated region of CtPAL possesses the maximum identity up to 96% to its orthologue in Cynara scolymus, while that of CtCHS retains the highest identity to its orthologue in Callistephus chinensis up to 96%. Experiments for gene expression profiling of CtPAL and CtCHS were performed after the treatment of seedlings with 0.1 and 1 mM SA (salicylic acid), wounding and salinity stress. The ...

Background: pABA biosynthesis is a potential target for antifolate drugs. Results: Rubreserine inhibits GAT-ADCS, an enzyme involved in pABA biosynthesis, and decreases the folate content in Arabidopsis and Toxoplasma. Conclusion: Specific inhibition of pABA synthesis induces growth limitation of plants and apicomplexan parasites. Significance: GAT-ADCS is a valuable target in eukaryotes, and rubreserine is a novel scaffold for anti-parasitic drugs. Glutamine amidotransferase/aminodeoxychorismate synthase (GAT-ADCS) is a bifunctional enzyme involved in the synthesis of p-aminobenzoate, a central component part of folate cofactors. GAT-ADCS is found in eukaryotic organisms autonomous for folate biosynthesis, such as plants or parasites of the phylum Apicomplexa. Based on an automated screening to search for new inhibitors of folate biosynthesis, we found that rubreserine was able to inhibit the glutamine amidotransferase activity of the plant GAT-ADCS with an apparent IC 50 of about 8 M. The growth rates of Arabidopsis thaliana, Toxoplasma gondii, and Plasmodium falciparum were inhibited by rubreserine with respective IC 50 values of 65, 20, and 1 M. The correlation between folate biosynthesis and growth inhibition was studied with Arabidopsis and Toxoplasma. In both organisms, the folate content was decreased by 40-50% in the presence of rubreserine. In both organisms, the addition of p-aminobenzoate or 5-formyltetrahydrofolate in the external medium restored the growth for inhibitor concentrations up to the IC 50 value, indicating that, within this range of concentrations, rubreserine was specific for folate biosynthesis. Rubreserine appeared to be more efficient than sulfonamides, antifolate drugs known to inhibit the invasion and proliferation of T. gon-dii in human fibroblasts. Altogether, these results validate the use of the bifunctional GAT-ADCS as an efficient drug target in eukaryotic cells and indicate that the chemical structure of rubreserine presents interesting anti-parasitic (toxoplasmosis, malaria) potential. Folates are a family of cofactors that are essential for cellular one-carbon (C1) transfer reactions. They are involved in several important metabolic pathways, such as the synthesis of nucleotides and the methylation cycle (1-3). Folate biosynthesis can be divided into three branches (Fig. 1A) as follows: the first one is for the pterin ring synthesis; the second one is for the pABA 5 synthesis, and the third one is for the assembly of these two precursors plus glutamates to form the backbone of folate derivatives (4-6). Blocking folate biosynthesis or turnover leads to the arrest of cell division and eventually to cell death. Antifolate drugs have been developed to exploit this feature in therapies against cancer cells and microbial or parasitic infections. Biosynthesis of folate is mainly inhibited by two groups of compounds, i.e. inhibitors of dihydropteroate synthase (DHPS) and inhibitors of dihydrofolate reductase (DHFR). Inhibitors of DHFR are commonly used as therapeutic agents against cancer (7), whereas a combination of these two types of inhibitors are * This work was supported in part the Région Rhône-Alpes (Cluster 9, "Plantacter"). □ S This article contains supplemental Fig. 1. 1 Ph.D. fellowship was supported by the Région Rhône-Alpes (Cluster 9, "Plantacter").

Responses of barley seedlings to water deficit (WD) induced by polyethylene glycol (PEG 6000) and ultraviolet (UV-B; 280-320 nm) radiation and their interaction (UV-B ? WD) were examined. A decrease in dry matter yield and water content of leaves and roots was observed following application of WD and UV-B ? WD, while no changes were found after treating barley plants with UV-B. Proline content was increased in leaves under WD conditions and UV-B ? WD. In contrast, UV-B treatment had no effect on the accumulation of proline in leaves of barley plants. Changes in root proline content showed a varied response: WD induced an increase in the level of this amino acid, while UV-B as well as UV-B ? WD suppressed root proline content. The lipid peroxidation product malondialdehyde (MDA) was increased in leaves under WD and UV-B ? WD stresses. Root MDA content increased in WD-stressed plants, but it decreased in the case of combined application of both stresses. The applied stress factors operated in a variable manner on phenylpropanoid metabolism. Phenylalanine ammonialyase (PAL) activity in leaves and roots was stimulated after exposure to WD and application of UV-B ? WD stresses, while UV-B stress did not affect its activity. On the other hand, UV-B treatment enhanced the activity of 4:coumarate-CoA ligase (4CL) in leaves and this enhancement was positively correlated with the accumulation of anthocyanins and flavonols. However, the combined application of WD and UV-B reduced the positive effect of UV-B on the accumulation of these compounds and the activity of 4CL. Surprisingly, anthocyanins and flavonols were not detected in roots of examined barley seedlings despite increased 4CL activity. The results suggest that UV-B-induced activation of 4CL as well as accumulation of anthocyanin and flavonols in leaves is beneficial for the response to this stress factor. On the other hand, WD-induced reduction of the effect of UV-B on 4CL activity and the contents of anthocyanin and flavonol might be a cause of membrane damage in UV-B-and WDstressed plants. In addition, conversely to what could be expected, the UV-B effect was perceived by the waterstressed roots, which exhibited reduced lipid peroxidation (MDA) and proline accumulation in WD-stressed plants exposed to UV-B.

Salicylic acid (SA) and its derivatives are the most widely known drugs in the world used to reduce pain and fever, helping to treat many inflammatory diseases, in the prevention of coronary heart disease and heart attacks, and in tumor suppression. This substance is also characterized by a high metabolic and physiological activity, which enables it to perform regulatory functions in plant development and reaction to biotic and abiotic stress factors. Under non-stress conditions, SA is present in plant tissues in quantities of several mg to several ng in one g of fresh mass. Its level substantially increases in plants exposed to water deficit. The accumulation of SA may result from its de novo synthesis through activation of enzymes involved in the synthesis of SA from phenylalanine, i.e. phenylalanine ammonia lyase (PAL) and benzoic-acid-2-hydroxylase (BA2H). SA accumulated in plants growing under the conditions of water shortage may be involved in the regulation of mechanisms responsible for resistance to drought through the control of water balance and activation of antioxidant system. Large body of evidences revealed that exogenous application of SA was effective in modeling plant responses to water deficit. Plant pre-treatment with SA resulted in higher tissue water content, increased activity of antioxidant enzymes, decreased level of lipid peroxidation and membrane injury and it also protected nitrate reductase activity against inhibition under water deficit conditions. These changes enable plants to survive under drought and play an essential role in countering the adverse effects of stress on growth and yield.

The aim of the paper was to determine the effect of water deficit (WD) and UV-B radiation acting individually and in combination on salicylic acid (SA) accumulation as well as on the activity of phenylalanine ammonia-lyase (PAL) and benzoic acid hydroxylase (BA2H) that control its biosynthetic route from phenylalanine. An additional aim was to test whether the interaction of these stresses limits the negative effect of a single stress on tissue hydration and membrane injury. Two-week-old seedlings were subjected to water deficit (WD), UV-B irradiation (UV-B) and three different combinations of WD and UV-B: (I) WD and UV-B applied at the same time, (II) UV-B applied before WD, and (III) WD applied before UV-B. Water deficit was imposed by immersing the root system in aerated nutrient solution with polyethylene glycol (PEG 6000) of water potential – 0.5 MPa. UV-B dosage was 24 kJ m −2  day −1 (0.84 W m −2 ) at the canopy level. UV-B and WD imposed individually and jointly, caused, in ...

The aim of the paper was to determine the effect of water deficit (WD) and UV-B radiation acting individually and in combination on salicylic acid (SA) accumulation as well as on the activity of phenylalanine ammonia-lyase (PAL) and benzoic acid hydroxylase (BA2H) that control its biosynthetic route from phenylalanine. An additional aim was to test whether the interaction of these stresses limits the negative effect of a single stress on tissue hydration and membrane injury. Two-week-old seedlings were subjected to water deficit (WD), UV-B irradiation (UV-B) and three different combinations of WD and UV-B: (I) WD and UV-B applied at the same time, (II) UV-B applied before WD, and (III) WD applied before UV-B. Water deficit was imposed by immersing the root system in aerated nutrient solution with polyethylene glycol (PEG 6000) of water potential-0.5 MPa. UV-B dosage was 24 kJ m −2 day −1 (0.84 W m −2) at the canopy level. UV-B and WD imposed individually and jointly, caused, in a time-dependent manner, an increase in SA content in both organs. Increased levels of SA in WD stressed plants were accompanied by an increase in the activity of PAL and BA2H. However, in plants exposed to UV-B were accompanied only by an increase in the activity of BA2H. Under WD conditions, an earlier increase of SA content was observed in roots than in leaves, which may indicate the involvement of SA in the signal transduction between roots and leaves. In plants exposed to sequential action of WD and UV-B, regardless of the order of its imposition, the effect of each single factor on SA accumulation in leaves was strengthened. WD had a greater effect on water loss and membrane injury than UV-B radiation. In plants exposed to WD after pre-treatment with UV-B radiation, a cross-tolerance mechanism was observed. Leaves of these plants did not show increased lipid peroxidation, measured in terms of malondialdehyde content, and a decrease in water content. This protective action was probably caused by the increase of the SA level in leaves of the UV-B treated plants prior to WD imposition.

Ozone (O3), a major photochemical oxidant, induces leaf injury concomitant with salicylic acid (SA) synthesis. In pathogen-infected leaves, SA is synthesized via two pathways, involving phenylalanine or isochorismate. SA biosynthesis under O3 fumigation is not well understood. When we applied 14C-labeled benzoic acid (a precursor of SA in the pathway via phenylalanine) to O3-exposed tobacco leaves, it was effectively metabolized to SA. However, the activity and mRNA level of isochorismate synthase (ICS) were not increased. In contrast, ICS activity was increased in O3-exposed Arabidopsis thaliana L. These results suggest that SA is synthesized via benzoic acid from phenylalanine in O3-exposed tobacco leaves but via isochorismate in Arabidopsis. Ethylene is a plant hormone that promotes leaf damage in O3-exposed plants. During O3 exposure, transgenic plants with a phenotype of reduced O3-induced ethylene production accumulated less SA than did wild-type plants. O3 increased the activ...

Bernard (1813-1878) is famous for his discoveries in physiology and for introducing rigorous experimental methods to medicine and biology. One of his major technical innovations was the use of chemicals in order to disrupt normal physiological function to test hypotheses. But less known is his conviction that the physiological functions of all living organisms rely on the same underlying principles. He hypothesized that similarly to animals, plants are also able to sense changes in their environment. He called this ability "sensitivity." In order to test his ideas, he performed anesthesia on plants and the results of these experiments were presented in 1878 in "Leçonssur les phénomènes de la vie communs aux animaux et aux végétaux." 1 The phenomena described by Claude Bernard more than a century ago are not fully understood yet. Here, we present a short overview of anesthetic effects in animals and we discuss how anesthesia affects plant movements, seed germination, and photosynthesis. Surprisingly, these phenomena may have ecological relevance, since stressed plants generate anesthetics such as ethylene and ether. Finally, we discuss Claude Bernard's interpretations and conclusions in the perspective of modern plant sciences.

Salvia mirzayanii and Salvia macrosiphon are medicinal and aromatic plants belonging to the Lamiaceae family, which have many pharmaceutical properties. In the present study, the nucleic acid sequences of small-subunit ribosomal RNAs (18s rRNA) were isolated from S. mirzayanii and S. macrosiphon and then the genetic diversity and phylogenetic relationships of these two species with 29 related Salvia species were investigated. Phenylalanine ammonia lyase (PAL1) was isolated from these two Salvia species. The phylogenetic and multi-alignment analyses of amino acids sequences of PAL1 revealed that PAL1 from both S. mirzayanii (GenBank accession no. KP336898) and S. macrosiphon (GenBank accession no. KP336899) has high identity with the other Salvia PALs in the GenBank (71%-96%) and has a closer relationship with other angiosperm species. Promoter analysis demonstrated that PAL includes cis-acting elements such as ABRE, ARE, HSE, TCA-elements, TC-rich repeat and GA, CGTCA, TGACG, WUNmotif in the upstream region which respond to stress hormones and might show its vital role in biotic and abiotic stresses. To investigate the effects of salinity on Salvia plants, twelve-week old seedlings of S. mirzayanii and S. macrosiphon were irrigated with 100 mM NaCl salinity. Leaf tissue was harvested at 0, 6, 12, 24 and 48 h after end of treatments for subsequent analyses. The results showed that salt stress could induce PAL1 expression (12 to 18 times) and subsequently increase PAL activity (42%-45%) and total phenolic accumulation (35%-43%) in the early hours after stress treatment. These results provide new information about molecular phylogeny of these two Salvia species and phenylpropanoid pathway under salt stress. Abbreviations: ABRE _ abscisic acid response element; ARE _ ABA-responsive element; HSE _ heat shock elements; MBS _ mybbinding site; MeJA _ methyl jasmonate; MSA-Like _ multiple system atrophy like; PAL _ phenylalanine ammonia lyase; WUNmotif _ wounding responsive element.

Salicylic acid (SA) is a prominent signaling molecule during biotic and abiotic stresses in plants biosynthesized via cinnamate and isochorismate pathways. Cinnamate 4-hydroxylase (C4H) and isochorismate synthase (ICS) are the main enzymes in phenylpropanoid and isochorismate pathways, respectively. To investigate the actual roles of these genes in resistance mechanism to environmental stresses, here, the coding sequences of these enzymes in safflower (Carthamus tinctorius), as an oilseed industrial medicinal plant, were partially isolated and their expression profiles during salinity stress, wounding, and salicylic acid treatment were monitored. As a result, safflower ICS (CtICS) and C4H (CtC4H) were induced in early time points after wounding (3-6 h). Upon salinity stress, CtICS and CtC4H were highly expressed for the periods of 6-24 h and 3-6 h after treatment, respectively. It seems evident that ICS expression level is SA concentration dependent as if safflower treatment with 1 mM SA could induce ICS much stronger than that with 0.1 mM, while C4H is less likely to be so. Based on phylogenetic analysis, safflower ICS has maximum similarity to its ortholog in Vitis vinifera up to 69%, while C4H shows the highest similarity to its ortholog in Echinacea angustifolia up to 96%. Overall, the isolated genes of CtICS and CtC4H in safflower could be considered in plant breeding programs for salinity tolerance as well as for pathogen resistance.