PAL Gene Expression Research Articles

Isolate-Specific Responses of the Nonhost Grass Brachypodium distachyon to the Fungal Pathogen Zymoseptoria tritici Compared with Wheat.

Septoria tritici blotch (STB) is an important foliar disease of wheat that is caused by the fungal pathogen Zymoseptoria tritici. The grass Brachypodium distachyon has been used previously as a model system for cereal-pathogen interactions. In this study, we examined the nonhost resistance (NHR) response of B. distachyon to two different Z. tritici isolates in comparison with wheat. These isolates vary in aggressiveness on wheat cultivar Remus, displaying significant differences in disease and pycnidia coverage. Using microscopy, we found that similar isolate-specific responses were observed for hydrogen peroxide accumulation and cell death in both wheat and B. distachyon. Despite this, induction of isolate-specific patterns of defense gene expression by Z. tritici did differ between B. distachyon and wheat. Our results suggest that expression of the phenylalanine ammonia lyase PAL gene may be important for NHR in B. distachyon, while pathogenesis-related PR genes and expression of genes regulating reactive oxygen species may be important to limit disease in wheat. Future studies of the B. distachyon-Z. tritici interaction may allow identification of conserved plant immunity targets that are responsible for the isolate-specific responses observed in both plant species.

Mutual relations between jasmonic acid and acibenzolar-S-methyl in the induction of resistance to the two-spotted spider mite (Tetranychus urticae) in apple trees

The possibility of inducing resistance to the two-spotted spider mite, Tetranychus urticae Koch, in ‘Gala’ apple trees growing under optimal fertilization or nitrogen-deficiency conditions was investigated. The effects of jasmonic acid (JA) at 1.5 and 2.5 mM, and acibenzolar-S-methyl (benzothiadiazole, BTH) at 0.5 and 1.5 mM, applied separately or together, on the fecundity of T. urticae females in a laboratory test as well as on the population growth of the pest in a greenhouse experiment were determined. The influence of both elicitors on the induction of LOX and PAL gene expression was assessed in a parallel experiment using real-time PCR. Jasmonic acid showed significantly higher effectiveness in inducing apple tree resistance to T. urticae, as compared to BTH. This was particularly evident in the reduction in pest numbers that was observed in the greenhouse experiment and was also confirmed by increased LOX gene expression after treatment with JA. BTH induced the expression of the PAL gene more strongly than jasmonic acid; however, this was not reflected in the performance of the two-spotted spider mite in the laboratory and greenhouse experiments. It was also found that the antagonistic effect of BTH on JA might lead to decreased effectiveness of the jasmonic acid used to induce apple tree resistance to the two-spotted spider mite. Although nitrogen fertilization stimulated the development of spider mite populations, the resistance induction mechanism was more effective in N-fertilized plants, which was especially evident at the higher jasmonic acid concentration.

THE EFFECT OF CHITOSAN ON GENE EXPRESSION, SOME MORPHOLOGICAL AND PHYSIOLOGICAL TRAITS OF SWEET BASIL (Ocimum basilicum L.) UNDER SALINITY STRESS

Sweet basil is an important medicinal plant belonging to Lamiaceae family. In this plant, Phenylpropanoid pathway possesses some enzymes involving in generating suitable essential oil constituents. The main purpose of conducting this study was to investigate the effects of chitosan on sweet basil’s growth and physiological parameters as well as gene expression subjected to salinity stress. After employing a foliar-spray of chitosan at 0 (as control) and 0.2 gl–1, the plants were subjected to salinity treatments at 0, 25, 50, 100, and 150 mM NaCl. The results of this research revealed that chitosan, compared to the controls, improved growth parameters under stressed or non-stressed conditions. In this regard, chitosan increased protein and chlorophyll contents as well as the expression of PAL and COVMT genes leading to an increase in phenolic compounds. To sum up, chitosan improved sweet basil tolerance to salinity through influencing the genes involved in the pathway of phenylpropanoid so as to produce secondary metabolites.

Enhanced stress tolerance in transformed Ajuga bracteosa Wall. ex Benth. regenerants by upregulated gene expression of metabolic pathways

The rol oncogenes of Agrobacterium rhizogenes enhance the production of medicinally important compounds in plants and provide a first barrier against the overproduction of reactive oxygen species during biotic and abiotic stress. 'this study was designed to evaluate the expression of genes involved in biosynthetic pathways and their impact on metabolic contents and environmental stress tolerance in regenerated Ajuga bracteosa Wall. ex Benth. After successful transformation, real-time quantitative PCR confirmed the increased expression (1.94-6.59-fold) of HMGR, HDS, FDS, PAL, and TTG1 genes in transgenic lines. Furthermore, GC-MS coupled with principal component analysis revealed diverse concentrations of 97 metabolites in A. bracteosa. Transgenic lines showed greater survival under multiple stresses. This was revealed by significant chlorophyll content (8.13-21 mu moles/m(2)), higher quantum efficiency of PSII (F-v/F-m), and the performance index (PIabs) value. Similarly, catalase and peroxidase enzyme activities were enhanced during extreme drought (300-400 mM mannitol) and salinity (150-200 mM NaCl) conditions, compared to untransformed control. Wild type control plant leaves were completely necrotized by Aspergillus fumigatus (FCBP 66) and Fusarium solani (FCBP 0291), whereas transformed leaves had improved antifungal resistance. In conclusion, our data suggest that rolABC genes have a significant impact on the synthesis of metabolites involved in enhancing multistress tolerance in A. bracteosa.

АНАЛИЗ ЭКСПРЕССИИ ГЕНОВ СТРЕССОУСТОЙЧИВОСТИ В УСЛОВИЯХ ВОЗДЕЙСТВИЯ ЗАСУХИ НА РАСТЕНИЯ БЕРЕЗЫ В ЦЕНТРАЛЬНО-ЧЕРНОЗЕМНОМ РЕГИОНЕ

Birch is one of the main deciduous forest-forming species in the European part of Russia, but the impact of stress (in particular, drought) greatly limits its distribution. In this regard, it seems relevant to identify resistance mechanisms in order to select promising genotypes for their further reproduction. The aim of this work is to identify drought-tolerant genotypes of European birch (B. pendula Roth.), pubescent birch (B. pubescens Ehrh.) аnd their hybrids. For the study, we have taken samples of birch at the age of 26 years, which remained viable after the droughts of 2010 and 2013. Birch leaves have been selected in the third decade of June 2019 to analyze drought resistance. Leaves of birch, selected during the period with optimal conditions of air temperature and precipitation, have been used as control ones. A modified CTAB method has been proposed for RNA isolation. We studied the expression of genes encoding proteins involved in the activation of cell defense pathways under the influence of abiotic stress (pal, PR-1, PR-10, lea8, DREB2) during the drought period (June 2019). A study of the expression of genes encoding proteins of metabolic pathways that are activated in response to abiotic stress (phenylpropanoid pathway) associated with the pathogenesis of proteins (PR1 and PR10), transcription factors (DREB2), and late embryogenesis proteins (LEA) has been made. As a result of the effects of drought, a significant increase in the expression of pal, PR-1, PR-10 and DREB2 genes has been detected in the analyzed samples. At the same time, changes in lea8 gene expression were detected for two out of ten genotypes. The largest increase in expression for all five genes is shown for birch samples 29-58 and 233. It indicates the development of adaptive mechanisms in these genotypes and can characterize them as the most stable. The studied genes can be recommended as markers for the analysis of stress resistance in various species of woody plants

Physiological and Molecular Effects of Silver Nanoparticles Exposure on Purslane (Portulaca oleracea L.)

Due to the antifungal and antibacterial properties, silver nanoparticles (AgNPs) are now widely used in consumer products. In this research, the effects of various concentrations of AgNPs (0, 2.5, 5, 10, 20, 40 and 80 ppm) on growth, contents of micro- and macroelements, physiological traits and expression of PAL and GSH genes of purslane (Portulaca oleracea L.) plants were investigated. The results showed that application of AgNPs resulted in a dose-dependent enhancement in accumulation of silver (Ag) in both root and leaf tissues, however, the Ag accumulated at the root more than the leaf at all levels of the AgNPs treatment. AgNPs treatment over 20 ppm reduced the growth, biomass production and accumulation of macroelements (Ca and Mg) and microelements (Zn, Cu, Mn and B) and increased contents of H2O2, MDA and DPPH scavenging activity. Application of AgNPs also increased the activity of antioxidant enzymes such as SOD, CAT and POD enzymes compared to control treatments. The activity and expression of PAL and CHS enzymes significantly increased under treatment of AgNPs. Our results indicate that increasing the activity of antioxidant enzymes and regulating the expression and activity of PAL and CHS enzymes are mechanisms to counteract the oxidative stress induced by AgNPs in the purslane plants.

Expression of PAL and PR2 pathogenesis related genes in barley plants challenged with closely related Pyrenophora species

Net blotch and leaf stripe caused by Pyrenophora teres and Pyrenophora graminea, respectively, are economical diseases of barley worldwide. Relatively little is known about the defense responses of barley challenged with these two closely related species. In the current work, expression of two well known defense-related genes PAL and PR2 were monitored in resistant and susceptible barley cultivars at early points of infection using quantitative real-time PCR (qPCR). Data showed significant variance in the expression patterns of the both genes between barley P. teres or P. graminea interactions as compared to the non-inoculated controls. It is also noteworthy that PAL and PR2 genes have a higher constitutive expression and faster induction in the resistant cultivar as compared with the susceptible one after infection with each pathogen. However, PCR (qPCR) analysis revealed higher gene expression in resistant barley plants inoculated with P. graminea as compared with P. teres, with a maximum expression for PR2 (13.8 and 6.41-fold) and PAL (14.8 and 7.89-fold) respectively, at 6 days post inoculation. The obtained results suggest that PAL and PR2 genes, positively regulate P. teres and P. graminea—resistance in barley plants during disease progress, which can provide testable hypotheses that will need direct future tests to determine how these changes may be specified in the genome of these closely related Pyrenophora species.

Metabolome and transcriptome profiling reveals quality variation and underlying regulation of three ecotypes for Cistanche deserticola.

Cistanche deserticola is a plant used both as food and medicine. We are interested in understanding how C. deserticola responds to environmental conditions. Samples were collected from three ecotypes grown in saline-alkali land, grassland and sandy land. Transcriptome and metabolome analysis were performed by using RNA-seq and LC-ESI-MS/MS. Among 578 metabolites identified, 218, 209 and 215 compounds were found differentially produced among the three ecotypes. Particularly, 2'-acetylacteoside, belonging to phenylethanoid glycosides (PhGs) is the most significantly differentially produced with a VIP > 0.5 and fold change > 2, representing a potential chemical marker to distinguish the three ecotypes. RNA-Seq analysis revealed 52,043 unigenes, and 947, 632 and 97 of them were found differentially expressed among the three ecotypes. Analysis of the correlation between the metabolome profiles and transcriptome profiles among three ecotypes identified that the 12 key genes related to PhGs biosynthesis were differentially expressed. Particularly, the expression of PAL, ALDH and GOT genes were significantly up-regulated in saline-alkali land compared to the other two. In summary, we found PhGs content was higher in saline-alkali land compared with other ecotypes. This is likely due to the up-regulation of the PhGs biosynthetic genes in response to the saline-alkali conditions.

Expression patterns of two pal genes of Pleurotus ostreatus across developmental stages and under heat stress

BackgroundPhenylalanine ammonia-lyase (PAL, EC 4.3.1.24) is the first key enzyme in the phenylpropanoid pathway. The pal gene has been widely studied in plants and participates in plant growth, development and defense systems. However, in Pleurotus ostreatus, the biological functions of pal during organismal development and exposure to abiotic stress have not been reported.ResultsIn this study, we cloned and characterized the pal1 (2232 bp) and pal2 (2244 bp) genes from the basidiomycete P. ostreatus CCMSSC 00389. The pal1 and pal2 genes are interrupted by 6 and 10 introns, respectively, and encode proteins of 743 and 747 amino acids, respectively. Furthermore, prokaryotic expression experiments showed that PAL enzymes catalyzed the conversion of L-phenylalanine to trans-cinnamic acid. The function of pal1 and pal2 was determined by constructing overexpression (OE) and RNA interference (RNAi) strains. The results showed that the two pal genes had similar expression patterns during different developmental stages. The expression of pal genes was higher in the reproductive growth stage than in the vegetative growth stage. And the interference of pal1 and pal2 delayed the formation of primordia. The results of heat stress assays showed that the RNAi-pal1 strains had enhanced mycelial tolerance to high temperature, while the RNAi-pal2 strains had enhanced mycelial resistance to H2O2.ConclusionsThese results indicate that two pal genes may play a similar role in the development of P. ostreatus fruiting bodies, but may alleviate stress through different regulatory pathways under heat stress.

A Plant Nutrient- and Microbial Protein-Based Resistance Inducer Elicits Wheat Cultivar-Dependent Resistance Against Zymoseptoria tritici.

The induction of plant defense mechanisms by resistance inducers is an attractive and innovative alternative to reduce the use of fungicides on wheat against Zymoseptoria tritici, the responsible agent of Septoria tritici blotch (STB). Under controlled conditions, we investigated the resistance induction in three wheat cultivars with different susceptible levels to STB as a response to a treatment with a sulfur, manganese sulfate, and protein-based resistance inducer (NECTAR Céréales). While no direct antigermination effect of the product was observed in planta, more than 50% reduction of both symptoms and sporulation were recorded on the three tested cultivars. However, an impact of the wheat genotype on resistance induction was highlighted, which affects host penetration, cell colonization, and the production of cell-wall degrading enzymes by the fungus. Moreover, in the most susceptible cultivar Alixan, the product upregulated POX2, PAL, PR1, and GLUC gene expression in both noninoculated and inoculated plants and CHIT2 in noninoculated plants only. In contrast, defense responses induced in Altigo, the most resistant cultivar, seem to be more specifically mediated by the phenylpropanoid pathway in noninoculated as well as inoculated plants, since PAL and CHS were most specifically upregulated in this cultivar. In Premio, the moderate resistant cultivar, NECTAR Céréales elicits mainly the octadecanoid pathway, via LOX and AOS induction in noninoculated plants. We concluded that this complex resistance-inducing product protects wheat against Z. tritici by stimulating the cultivar-dependent plant defense mechanisms.

Iron oxide nanoparticles: a novel elicitor to enhance anticancer flavonoid production and gene expression in Dracocephalum kotschyi hairy‐root cultures

Dracocephalum kotschyi Boiss. is a valuable source of rosmarinic acid (RA) and methoxylated hydroxyflavones (such as xanthomicrol and cirsimaritin) with antioxidative and antiplatelet effects and with antiproliferative potential against various cancer cells. The extensive application of nanotechnology in hairy root cultures is a new sustainable production platform for producing these active constituents. In the present study, hairy roots derived from 4-week-old leaves and Agrobacterium rhizogenes strain ATCC15834 were used to investigate the impact of various concentrations of iron oxide nanoparticles (Fe NPs) in two elicitation time exposures (24 and 48 h) on growth, antioxidant enzyme activity, total phenolic and flavonoid content (TPC and TFC), and some polyphenols. Gene expression levels of phenylalanine ammonia-lyase (pal) and rosmarinic acid synthase (ras) were also analyzed. Iron nanoparticles enhanced biomass accumulation in hairy roots. The treatment time and Fe NP dosage largely improved the activity of antioxidant enzymes, TPC and TFC. The highest RA (1194 μg g-1 FW) content (9.7-fold), compared to controls, was detected with 24 h of exposure to 75 mg L-1 Fe NP, which was consistent with the expression of pal and ras genes under the influence of elicitation. The xanthomicrol, cirsimaritin, and isokaempferide content was increased 11.87, 3.85, and 2.27-fold, respectively. Stimulation of D. kotschyi hairy roots by Fe NPs led to a significant increase in the induction and production of important pharmaceutical compounds such as rosmarinic acid and xanthomicrol. © 2019 Society of Chemical Industry.

Melatonin treatment promotes endogenous melatonin accumulation and triggers GABA shunt pathway activity in tomato fruits during cold storage

Higher H2O2 accumulation in tomato fruits during storage at 4 °C for 7 days by melatonin treatment at 100 μM may serve as signaling molecule for promoting endogenous melatonin accumulation by trigerring melatonin biosynthesis TDC, T5H, SNAT, and ASMT genes expression during storage at 4 °C for 28 days. Also, higher GABA shunt pathway activity demonstrating by higher GAD, GABA-T and SSADH enzymes activity in tomato fruits treated with melatonin may be responsible for promoting phenylpropanoid pathway activity demonstrating by higher PAL gene expression and enzyme activity giving rise to higher phenols accumulation and higher DPPH scavenging capacity during storage at 4 °C for 28 days. Hence, exogenous melatonin treatment may serve as beneficial procedure for response to chilling stress in tomato fruits by signaling H2O2 accumulation responsible for promoting endogenous melatonin accumulation accompanying by stimulating GABA shunt pathway activity.

The role of arbuscular mycorrhizal fungi on acclimatization of micropropagated plantlet Satureja khuzistanica Jam. by ameliorating of antioxidant activity and expression of PAL gene

In this study, the effect of mycorrhiza on the antioxidative system of Satureja khuzistanica plantlet has been investigated to increase its compatibility on ex vitro conditions. The relative gene expression of PAL, total flavonoid rate, activity of PAL enzyme, antioxidative enzymes and the rate of membrane lipid peroxidation in micropropagated plantlet after inoculation were measured in four steps after being transferred to ex vitro conditions. The relative expression of PAL gene (biosynthesis gene of flavonoids) increased in the leaves and roots of AM plantlets compared with non-inoculated plantlet. Increasing the relative gene expression of PAL increased the biosynthesis of the PAL enzyme and subsequently flavonoids in AM plantlets which leads to the integrity of the membrane and inhibition of oxidative damage in transition stress conditions. The enhancement of antioxidant enzymes (catalase, peroxidase) in the non-inoculated plantlet indicates that the rate of oxidative stress in the control plantlet is higher than AM plantlet. The higher amount of the rate of membrane lipid peroxidation in non-inoculated plantlet showed that the transition stress has enhanced the peroxidation of lipids, therefor, AM is able to help the plantlet to exhibit more resistant to this stress. By increasing the gene expression of the biosynthetic pathway of the flavonoids, it reduces the oxidative stress on the tissue culture plants.

Benzothiadiazole and B-Aminobutyricacid Induce Resistance to Ectropis Obliqua in Tea Plants (Camellia Sinensis (L.) O. Kuntz).

In order to investigate the effect of benzothiadiazole (BTH) and β-aminobutyric acid (BABA) on the resistance of tea plants (Camellia sinensis) to tea geometrid (Ectropis obliqua), three levels each of benzothiadiazole (BTH) and β-aminobutyric acid (BABA) were sprayed on 10-year-old tea plants. Generally PPO and PAL activities increased with low concentrations of BTH and BABA treatments. Quantitative RT-PCR revealed a 1.43 and 2.72-fold increase in PPO gene expression, and 3.26 and 3.99-fold increase in PAL gene expression with 75 mg/L BTH and 400 mg/L BABA respectively. Analysis of hydrolysis of synthetic substrates also revealed that chymotrypsin-like enzyme activity present in larval midgut extracts was not significantly inhibited by BTH and BABA. However, proteinase activity was found to be inversely proportional to the age of tea geometrid. Larvae pupation rate decreased by 8.10, 10.81 and 21.62% when tea geometrid were fed with leaves treated with 25, 50 and 75 mg/L BTH solutions, while 100, 200 and 400 mg/L BABA solutions decreased same by 8.10, 16.21 and 13.51% respectively. Also, larvae development period delayed to 23.33 and 26.33 days with 75 mg/L BTH and 400 mg/L BABA treatments respectively. The results in this study; therefore, suggest that benzothiadiazole (BTH) and β-aminobutyric acid (BABA) play a role in inducing resistance in tea plants to tea geometrid, with the optimal effect achieved at BTH-3 (75 mg/L) and BABA-3 (400 mg/L), respectively.

Growth enhancement and salt tolerance of Safflower (Carthamus tinctorius L.), by salicylic acid

It has been shown that salicylic acid acts as an endogenous signal molecule responsible for inducing stress tolerance in plants. The effect of SA (1 mM) and sodium chloride (0, 100, and 200 mM NaCl) on some biochemical and molecular responses of safflower plants was studied. Plants were harvested randomly at 21 days after the start of treatments. Results revealed that chlorophyll and total soluble protein contents decreased under salinity, however proline, glycine betaine, carbohydrate, total carotenoids, flavonoid, and anthocyanin contents, as well as PAL gene expression increased. The exogenous SA improved the response of safflower to salinity by increasing glycine betaine, total soluble protein, carbohydrates, chlorophylls, carotenoids, flavonoid, and anthocyanin contents. In addition, qRT-PCR analysis showed that exogenous SA induced expression of PAL gene in both salt-treated and untreated plants. Moreover, SA application under saline conditions decreased the levels of proline which could indicate successful acclimatization of these plants to saline conditions. Our data suggested that the exogenous SA played a key role in stress condition through regulation of osmotic adjustment and antioxidant system due to some compounds. These results provide novel insights about the physiological and molecular role of SA in salt resistance. Therefore, this component can be considered due to low price and availability.

Enhancement of paclitaxel content in induced tetraploid Corylus avellana L. cell suspension culture with regulating the expression of genes in paclitaxel biosynthetic pathway

During recent years, hazel cell suspension culture has been significantly considered as a new important source of paclitaxel. Artificial polyploidy alters different characters in plants which results in amplifying the secondary metabolites in medicinal plants. In this paper, the effects of tetraploidy induction on paclitaxel content and gene expression in hazel cell suspension culture were investigated. Various concentrations of colchicine and duration of exposure in solid and liquid media were examined and the ploidy level of cells was determined using flow cytometric analysis. The tetraploid cells were obtained from 0.2% colchicine in the exposure time of 5 and 6 days in solid medium and 0.3% colchicine in the exposure time of 3 and 4 days in liquid medium. Tetraploid cells were employed to prepare cell suspension. 3 µM of phenylalanine and 0.05 mM of vanadyl sulfate were added to both tetraploid and diploid (control) suspension to elicit paclitaxel induction. High performance liquid chromatography analysis demonstrated that the tetraploid cell suspensions produced paclitaxel of about [9.88 µg g−1 (DW)] 1.7-fold compared with diploid cells [5.74 µg g−1 (DW)]. The application of phenylalanine and vanadyl sulfate increased the concentration of paclitaxel in both diploid and tetraploid cells. Moreover, qRT-PCR analysis showed that the expression of GGPPS gene was significantly increased and PAL gene expression was altered after tetraploidization.

Fungal chitosan for growth and PAL gene expression of Dendrobium Sonia ‘Bom 17’ in vitro

Fungal chitosan for growth and <i>PAL</i> gene expression of <i>Dendrobium</i> Sonia ‘Bom 17’ in vitro

T1N6_22 positively regulates Botrytis cinerea resistance but negatively regulates Pseudomonas syringae pv. tomato DC3000 resistance in Arabidopsis thaliana

ABSTRACTT1N6_22, a short-chain dehydrogenase/reductase family protein, was identified as a positive regulator in Arabidopsis thaliana resistance against Botrytis cinerea and Alternaria brassicae in our preliminary study. In this study, we found that the expression levels of the T1N6_22 gene were induced and up-regulated in A. thaliana ecotype Columbia (Col-0) after B. cinerea and Pseudomonas syringae pv. tomato DC3000 inoculation. Compared with the Col-0 and t1n6_22/T1N6_22 plants, the expression of PAL, PR4, PPO, SOD and CAT genes were down-regulated in the t1n6_22 plants. In Col-0 plants treated with salicylic acid (SA) and the SA analogue benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester (BTH), the expression levels of T1N6_22 were significantly enhanced, whereas the expression levels of T1N6_22 were reduced by jasmonic acid treatment. Meanwhile, the t1n6_22 mutant exhibited enhanced resistance, whereas the wild-type Col-0 and complemented plants (t1n6_22/T1N6_22) showed susceptibility to Pst DC3000. After inoculation with B. cinerea and Pst DC3000, the expression levels of defence-related genes PR1, PR3, PR5, NPR1 and PDF1.2 in t1n6_22 were significantly different from those in Col-0 and t1n6_22/T1N6_22 plants. Taken together, the T1N6_22 gene played a negative role in Arabidopsis resistance to Pst DC3000. The T1N6_22 gene may be involved in the regulation of salicylic acid and jasmonic-acid–signalling pathways to affect the resistance of Arabidopsis to B. cinerea and Pst DC3000.

Elicitation of Phenylpropanoids and Expression Analysis of PAL Gene in Suspension Cell Culture of Ocimum tenuiflorum L.

The accumulation of total phenylpropanoids and the real time expression of PAL genes in Ocimum tenuiflorum suspension cell cultures were investigated. A comprehensive analysis of the effects of various abiotic elicitors like jasmonic acid (JA), methyl jasmonate (MeJA), salicylic acid (SA) and precursor feeder L-phenylalanine (L-phe) was done in O. tenuiflorum suspension cell cultures during elicitation. Ultra performance liquid chromatography based metabolite profiling revealed differential accumulation of three pharmaceutically important phenylpropanoids: caffeic acid, vanillin and ferulic acid. This accumulation corroborated well with real time expression of PAL genes. Biomass analysis during elicitation showed L-phe and JA moderately and MeJA and SA marginally affected the cell growth. Single and repetitive feeding with L-phe induced 22.5 fold accumulations in caffeic acid, ferulic acid and vanillin on day 16 with PAL expression increasing by 9.8–12 fold. SA (1.5 mM) induced 61 fold increase in caffeic acid accumulation with PAL expressions raised by 4.5 fold. MeJA at 25 µM promoted ferulic acid production up to 62 fold having PAL expression raised by seven fold on day 16 of elicitor treatment. Enhanced accumulation of total phenylpropanoids and elevated expression of PAL gene were observed during the course of treatment with elicitors and precursor feeder. This stipulates that PAL may modulate the biosynthesis of phenylpropanoids especially vanillin, caffeic acid and ferulic acid. The present study is of particular significance for using suspension cell culture systems of O. tenuiflorum, a less explored plant, for biotechnological production of pharmaceutically important plant secondary metabolites.

Expression of genes, encoded defense proteins, in potato plants infected with the cyst-forming nematode Globodera rostochiensis (Wollenweber 1923) Behrens, 1975 and modulation of their activity during short-term exposure to low temperatures

The expression of the principal genes providing an immune response in the roots of potato plants resistant and susceptible to the cyst nematode Globodera rostochiensis is investigated under conditions of infestation and with frequent variations in temperature. Differences in the immune status of resistant and susceptible potato cultivars are revealed in the level of expression of R-genes (H1 and Gro1-4), gene PAL, and defense genes of the PR-family (PR1, PR2, PR3, PR6). Varying the temperature changes the activity of transcriptome of susceptible plants towards activation of expression of R-genes, gene PAL, and defense genes; interactions between the plant and parasite are displaced towards induction of host resistance.