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Methyl Jasmonate (methyl + jasmonate)
Terms modified by Methyl Jasmonate Selected AbstractsSynthesis of cis-Hedione® and Methyl Jasmonate via Cascade Baylis,Hillman Reaction and Claisen Ortho Ester RearrangementHELVETICA CHIMICA ACTA, Issue 12 2005Christian Chapuis The exocyclically unsaturated conjugated keto esters 10, obtained via a Claisen ortho ester rearrangement of the allylic hydroxy ketones 9, were either directly hydrogenated or partially isomerized into the endocyclically unsaturated tetrasubstituted didehydrojasmonoid intermediates 14, prior to a more selective hydrogenation with Pd/C in cyclohexane to the disubstituted oxocyclopentaneacetates 15 (Scheme,2). The key intermediates 9 were obtained either by a four-step sequence, including acetal protection/deprotection from enone 1, in the specific case of hydroxy ketone 9a (Scheme,1), or more directly and generally by a Baylis,Hillman reaction from cyclopent-2-en-1-one (16) and the appropriate aldehydes 17 (Scheme,2). The judicious choice of these aldehydes opens versatile modifications for the stereoselective introduction of the partially cis - or epimerized trans -C(2) jasmonoid side chain, while the Baylis,Hillman reaction, catalyzed by chiral [1,1,-binaphthalene]-2,2,-diols (BINOLs) 19 (Scheme,3), may be efficiently conducted in a one-pot cascade fashion including the ortho ester Claisen rearrangement. [source] REDUCTION IN MICROBIAL GROWTH AND IMPROVEMENT OF STORAGE QUALITY IN FRESH-CUT PINEAPPLE AFTER METHYL JASMONATE TREATMENTJOURNAL OF FOOD QUALITY, Issue 1 2005MAGALY MARTÍNEZ-FERRER ABSTRACT Maintaining the quality of a fresh-cut fruit or vegetable product is a major concern and a priority in the development and in the production of fresh-cut produce products of the industry. The industry has been searching for alternative methods to protect fresh-cut produce from decay and to prolong shelf life. The objective of this research is to enhance the quality and the shelf life of fresh-cut pineapple by exposure to methyl jasmonate (MJ). The exposure of the diced pineapple to a MJ emulsion at a concentration of 10,4 M for 5 min in a sealed container decreased microbiological growth by 3 logs after 12 days of storage at 7C, compared with the control pineapple. Methyl jasmonate as vapor or as dip did not affect the firmness or the color of the fruit. Methyl jasmonate may be a practical treatment to ensure the safety and the quality of fresh-cut pineapple and other fruits and vegetables. [source] Oxytetracycline inactivation by putative reactive oxygen species released to nutrient medium of Helianthus annuus hairy root cultures,BIOTECHNOLOGY & BIOENGINEERING, Issue 4 2005Ninad P. Gujarathi Abstract When subjected to stress, plants produce reactive oxygen species (ROS) as a part of the defense response. The oxidative response is also used to degrade organic pollutants. Hairy roots of Helianthus annuus (sunflower) are shown to oxidize oxytetracycline (OTC) through the action of the ROS released to the nutrient medium by the hairy root cultures. Methyl jasmonate (MeJA) elicits ROS formation in the hairy root cultures. The activities of the antioxidant enzymes, ascorbate peroxidase (APX), catalase (CAT), and guaiacol peroxidase (GPX), are reported for hairy root cultures treated with increasing concentrations of MeJA. A bioassay using Enterococcus hirae as the test microorganism demonstrates the root-catalyzed oxidation process results in conversion of OTC into product(s) devoid of antibiotic activity. Direct evidence for putative ROS oxidation of OTC is obtained by mass spectrometry (MS) and HPLC/MS showing first quinone formation followed possibly by ring cleavage, which disrupts UV absorption and destroys antibiotic activity. © 2005 Wiley Periodicals, Inc. [source] Impact of chemical elicitor applications on greenhouse tomato plants and population growth of the green peach aphid, Myzus persicaeENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 3 2006Anthony J. Boughton Abstract Recent advances in the understanding of plant signaling pathways have opened the way for using elicitor-induced plant resistance as a tactic for protecting plants against arthropod pests. Four common elicitors of induced responses in tomato, Lycopersicon esculentum Mill. (Solanaceae), were evaluated with regard to phytotoxicity, induction of plant defensive proteins, and effects on population growth and fecundity of a common pest, the green peach aphid, Myzus persicae (Sulzer) (Homoptera: Aphididae). Ethephon and methyl jasmonate (MJ) treatments caused varying degrees of phytotoxicity. Ethephon caused pronounced changes in plant growth form and severe, dose-dependent negative impacts on plant growth and flowering. Effects with MJ were milder, but still caused temporary inhibition of development, leading to smaller plants and delayed flowering. The commercial elicitors benzothiadiazole (BTH) and harpin did not cause detectable phytotoxicity. The highest doses of ethephon and MJ significantly increased leaf peroxidase (POD) levels but only MJ treatments significantly increased polyphenol oxidase (PPO) levels. BTH and harpin had no detectable effects on POD and PPO. Populations of green peach aphids grew significantly more slowly on plants treated with BTH or MJ than on control plants or plants treated with harpin or ethephon. Slowed aphid population growth on BTH-treated plants was due to significant reductions in aphid fecundity, although this was independent of changes in time to onset of reproduction or time to death. Aphid fecundity was also reduced on MJ-treated plants relative to controls, but this difference was not statistically significant, suggesting that other mechanisms are involved in slowing aphid population growth on MJ-treated plants. Growth of aphid populations on plants treated with a MJ,BTH mixture was reduced almost as much as with treatments of MJ alone, suggesting that antagonism between JA-dependant and SA-dependent plant signaling pathways is only mild with regard to induced defenses against aphids. [source] NtKTI1, a Kunitz trypsin inhibitor with antifungal activity from Nicotiana tabacum, plays an important role in tobacco's defense responseFEBS JOURNAL, Issue 19 2010Hao Huang A cDNA library from tobacco inoculated with Rhizoctonia solani was constructed, and several cDNA fragments were identified by differential hybridization screening. One cDNA clone that was dramatically repressed, NtKTI1, was confirmed as a member of the Kunitz plant proteinase inhibitor family. RT-PCR analysis revealed that NtKTI1 was constitutively expressed throughout the whole plant and preferentially expressed in the roots and stems. Furthermore, RT-PCR analysis showed that NtKTI1 expression was repressed after R. solani inoculation, mechanical wounding and salicylic acid treatment, but was unaffected by methyl jasmonate, abscisic acid and NaCl treatment. In vitro assays showed that NtKTI1 exerted prominent antifungal activity towards R. solani and moderate antifungal activity against Rhizopus nigricans and Phytophthora parasitica var. nicotianae. Bioassays of transgenic tobacco demonstrated that overexpression of NtKTI1 enhanced significantly the resistance of tobacco against R. solani, and the antisense lines exhibited higher susceptibility than control lines towards the phytopathogen. Taken together, these studies suggest that NtKTI1 may be a functional Kunitz trypsin inhibitor with antifungal activity against several important phytopathogens in the tobacco defense response. [source] Analysis of the enantiomeric ratios of chiral components in absolute jasmineFLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2001S. Tamogami Abstract Determination of the enantiomeric ratios of chiral components in absolute jasmine, an important raw fragrance material, was studied. Jasmine oils from Egypt, India and France were employed. It was remarkable that the enantiomeric excess of most of these chiral components was not 100% ee. There was a significant difference in the ratios of enantiomers of several characteristic aroma compounds among these products. In particular methyl jasmonate in Indian jasmine oil contains less of the major (1R, 2R)-isomer compared with those of France and Egypt. Copyright © 2001 John Wiley & Sons, Ltd. [source] Effects of systemic potato response to wounding and jasmonate on the aphid Macrosiphum euphorbiae (Sternorryncha: Aphididae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 7 2010L. Brunissen Abstract Plant induced responses are activated by multiple biotic and abiotic stresses, and may affect the interactions between a plant and phytophagous insects. The objective of this work was to evaluate the effects of different stresses inflicted to potato plants (Solanum tuberosum) on the potato aphid (Macrosiphum euphorbiae). Abiotic wounding, biotic wounding by Leptinotarsa decemlineata and treatment with volatile methyl jasmonate (MeJA) were evaluated with regard to the orientation behaviour, the feeding behaviour and the development of the potato aphids. Dual-choice olfactometry showed that plants treated with MeJA lost their attractiveness for the potato aphids, while both abiotic and biotic wounding did not alter the orientation of aphids. Electropenetrography revealed that the feeding behaviour of aphids was only slightly disturbed by a previous L. decemlineata wounding, while it was highly disturbed by mechanical wounding and MeJA treatment. Aphid nymph survival was reduced on mechanically wounded plants, the pre-reproductive period was lengthened and the fecundity reduced on plants treated with MeJA. Our results bring new information about the effects of various stresses inflicted to S. tuberosum on M. euphorbiae. We showed that wounding and MeJA treatment induced an antixenosis resistance in potato plants against M. euphorbiae, which may influence aphid colonization processes. [source] CYSTATIN ACCUMULATION IN TOMATO LEAVES AFTER METHYL JASMONATE TREATMENT OR MECHANICAL INJURYJOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2002JU WEN WU The elicitation of cystatin accumulation in tomato leaves was studied with mature and seedling cv. Bonnie Best. Repetitive mechanical injury (MI) or methyl jasmonate (MJ) treatment of seedlings elicited plentiful cystatin accumulation in the leaves when plants were held at 30C under continuous lighting. Cystatin accumulation in leaves of MI seedlings decreased by 50% when incubated at a reduced light period of 12 h light/day. Cystatin accumulation in MJ treated plants was not influenced by reducing the light period from 24 h to 12 h/day. Cystatin accumulation after MJ treatment was optimal at 35C and negligible at 40C. At ambient field conditions (I8,33C), MJ treated seedlings still accumulated a significant amount of cystatin; however, very little cystatin accumulated in leaves of MI seedlings under these conditions of lower temperature and light exposure. The leaves of mature plants accumulated less cystatin after MJ or MI treatment than did those of seedlings. [source] REDUCTION IN MICROBIAL GROWTH AND IMPROVEMENT OF STORAGE QUALITY IN FRESH-CUT PINEAPPLE AFTER METHYL JASMONATE TREATMENTJOURNAL OF FOOD QUALITY, Issue 1 2005MAGALY MARTÍNEZ-FERRER ABSTRACT Maintaining the quality of a fresh-cut fruit or vegetable product is a major concern and a priority in the development and in the production of fresh-cut produce products of the industry. The industry has been searching for alternative methods to protect fresh-cut produce from decay and to prolong shelf life. The objective of this research is to enhance the quality and the shelf life of fresh-cut pineapple by exposure to methyl jasmonate (MJ). The exposure of the diced pineapple to a MJ emulsion at a concentration of 10,4 M for 5 min in a sealed container decreased microbiological growth by 3 logs after 12 days of storage at 7C, compared with the control pineapple. Methyl jasmonate as vapor or as dip did not affect the firmness or the color of the fruit. Methyl jasmonate may be a practical treatment to ensure the safety and the quality of fresh-cut pineapple and other fruits and vegetables. [source] W55a Encodes a Novel Protein Kinase That Is Involved in Multiple Stress ResponsesJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 1 2009Zhao-Shi Xu Abstract Protein kinases play crucial roles in response to external environment stress signals. A putative protein kinase, W55a, belonging to SNF1-related protein kinase 2 (SnRK2) subfamily, was isolated from a cDNA library of drought-treated wheat seedlings. The entire length of W55a was obtained using rapid amplification of 5, cDNA ends (5,-RACE) and reverse transcription-polymerase chain reaction(RT-PCR). It contains a 1 029 -bp open reading frame (ORF) encoding 342 amino acids. The deduced amino acid sequence of W55a had eleven conserved catalytic subdomains and one Ser/Thr protein kinase active-site that characterize Ser/Thr protein kinases. Phylogenetic analysis showed that W55a was 90.38% homologous with rice SAPK1, a member of the SnRK2 family. Using nullisomic-tetrasomic and ditelocentric lines of Chinese Spring, W55a was located on chromosome 2BS. Expression pattern analysis revealed that W55a was upregulated by drought and salt, exogenous abscisic acid, salicylic acid, ethylene and methyl jasmonate, but was not responsive to cold stress. In addition, W55a transcripts were abundant in leaves, but not in roots or stems, under environmental stresses. Transgenic Arabidopsis plants overexpressing W55a exhibited higher tolerance to drought. Based on these findings, W55a encodes a novel dehydration-responsive protein kinase that is involved in multiple stress signal transductions. [source] Syntheses of deuterated jasmonates for mass spectrometry and metabolism studiesJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 11 2005Patrycja W. Galka Abstract Jasmonic acid and its metabolites play an essential role in the regulation of plant development and systemic defense responses. Isotopically labeled standards are required to quantify plant hormones for metabolism studies using mass spectrometry. A convenient method for the preparation of deuterated analogs of jasmonates is demonstrated. Modification of commercially available methyl jasmonate by base-catalyzed proton/deuterium exchange or Wittig reaction introduces either two or three heavy atoms into a molecule. Copyright © 2005 John Wiley & Sons, Ltd. [source] Through oven transfer adsorption,desorption interface for the analysis of methyl jasmonate in aromatic samples by on-line RPLC-GCJOURNAL OF SEPARATION SCIENCE, JSS, Issue 6-7 2008Gema Flores Abstract A fully automated method for the determination of medium volatility compounds in aromatic samples was developed. Specifically, the determination of methyl jasmonate in jasmine fragrances was performed by using the through oven transfer adsorption,desorption (TOTAD) interface for the on-line coupling between RPLC-GC. A study of the most relevant variables involved in the performance of the TOTAD interface for medium volatility compounds was carried out by testing different values of helium flow (100, 300, 400, and 500 mL/min), transfer speed (0.1, 0.3, 0.5, and 2.0 mL/min), and methanol/water percentages (86:14, 85:15, 83:17, 80:20, and 70:30). The method developed provided satisfactory repeatability (RSD for retention times of 0.15% and for peak areas of 9.4%) and recovery (71%) as well as excellent LOD (0.01 mg/L) for methyl jasmonate in commercial jasmine essence under the experimental conditions selected as optimum. Additional advantages of the automated RPLC-TOTAD-GC method proposed in the present work are its rapidness, reliability, and the possibility of directly introducing the sample with no further pretreatment. [source] Enantiomeric purity of (+/,)-methyl jasmonate in fresh leaf samples and commercial fragrancesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 13 2007Maria L. Ruiz del Castillo Abstract The enantiomeric purity of (+/,)-methyl jasmonate in fresh leaf material of Jasminum from different species and Rosmarinus officinalis was examined by solid-phase microextraction-GC-MS (SPME-GC-MS). For comparison with these natural products, commercial jasmine and rosemary fragrances were also studied. The extraction conditions were selected as a result of testing different values of temperature (40, 50, and 60°C) and time (2, 15, 30, and 40 min). The results obtained in this work revealed a range of enantiomeric excesses for (+/,)-methyl jasmonate varying from 13 to 95% depending on the Jasminum specie considered. In contrast, (,)-methyl jasmonate always occurred as a pure enantiomer in all R. officinalis samples studied. This implies those Jasminum species in which the enantiomeric purity of (,)-methyl jasmonate is high enough and any R. officinalis sample might be used as natural sources of pure (,)-methyl jasmonate. Concerning the commercial fragrances, those of jasmine showed enantiomeric composition of (,)-methyl jasmonate ranging from 1 to 15% whereas those of rosemary exhibited practically the pure (,)-methyl jasmonate. This fact suggests the addition and nonaddition of the racemic mixture of methyl jasmonate to the commercial jasmine and rosemary samples, respectively. [source] Salicylic acid confers resistance to a biotrophic rust pathogen, Puccinia substriata, in pearl millet (Pennisetum glaucum)MOLECULAR PLANT PATHOLOGY, Issue 2 2009BRIDGET G. CRAMPTON SUMMARY Studies were undertaken to assess the induction of defence response pathways in pearl millet (Pennisetum glaucum) in response to infection with the leaf rust fungus Puccinia substriata. Pretreatment of pearl millet with salicylic acid (SA) conferred resistance to a virulent isolate of the rust fungus, whereas methyl jasmonate (MeJA) did not significantly reduce infection levels. These results suggest that the SA defence pathway is involved in rust resistance. In order to identify pearl millet genes that are specifically regulated in response to SA and not MeJA, and thus could play a role in resistance to P. substriata, gene expression profiling was performed. Substantial overlap in gene expression responses between the treatments was observed, with MeJA and SA treatments exhibiting 17% co-regulated transcripts. However, 34% of transcripts were differentially expressed in response to SA treatment, but not in response to MeJA treatment. SA-responsive transcripts represented genes involved in SA metabolism, defence response, signal transduction, protection from oxidative stress and photosynthesis. The expression profiles of pearl millet plants after treatment with SA or MeJA were more similar to one another than to the response during a compatible infection with P. substriata. However, some SA-responsive genes were repressed during P. substriata infection, indicating possible manipulation of host responses by the pathogen. [source] The potato StLTPa7 gene displays a complex Ca2+ -associated pattern of expression during the early stage of potato,Ralstonia solanacearum interactionMOLECULAR PLANT PATHOLOGY, Issue 1 2009GANG GAO SUMMARY Although nonspecific lipid transfer proteins (nsLTPs) are widely expressed during plant defence responses to pathogens, their functions and regulation are not fully understood. In this article, we report the isolation of a cDNA for the new nsLTP, StLTPa7, from cultivated potato (Solanum tuberosum) infected with Ralstonia solanacearum. The cDNA was predicted to encode a type 1 nsLTP containing an N-terminal signal sequence and possessing the characteristic features of nsLTPs. A phylogenetic analysis showed that the encoded amino acid sequence of the nsLTP was similar to those of other previously reported plant nsLTPs, which contain a putative calmodulin-binding site consisting of approximately 12 highly conserved amino acid residues. The expression of the StLTPa7 gene was studied during the early stages of potato,R. solanacearum interaction using real-time quantitative polymerase chain reaction (qRT-PCR) and Northern analyses, and a complex calcium (Ca2+)-associated pattern of expression was observed with the following features: (i) transcripts of the StLTPa7 gene were systemically up-regulated by infection with R. solanacearum; (ii) the StLTPa7 gene was stimulated by salicylic acid, methyl jasmonate, abscisic acid and Ca2+; (iii) qRT-PCR showed that, during the early stage of R. solanacearum infection, nsLTP transcripts accumulated over a time course that paralleled that of Ca2+ accumulation, detected using environmental scanning electron microscopy and energy-dispersive X-ray (EDAX) spectrometry; and (iv) the Ca2+ channel blocker, ruthenium red, partially blocked R. solanacearum -induced StLTPa7 expression. This report represents the first use of EDAX analysis to establish a synchrony between Ca2+ accumulation and nsLTP expression in response to potato,R. solanacearum interactions. Collectively, these results suggest that StLTPa7 may be a pathogen- and Ca2+ -responsive plant defence gene. [source] Overexpression of the apple alcohol acyltransferase gene alters the profile of volatile blends in transgenic tobacco leavesPHYSIOLOGIA PLANTARUM, Issue 3 2008Dapeng Li Alcohol acyltransferases (AATs) are key enzymes in ester biosynthesis. Previous studies have found that AAT may be a stress-related gene. To investigate further the function of the apple alcohol acyltransferase gene (MdAAT2), transgenic tobacco plants overexpressing MdAAT2 were generated. Gas chromatography,mass spectroscopy analysis showed that the volatile blends were altered in these transgenic tobacco leaves. Although no apple-fruity volatile esters were detected in transgenic tobacco leaves, methyl caprylate, methyl caprate, and methyl dodecanoate were newly generated, and the concentrations of methyl benzoate and methyl tetradecanoate were significantly increased, suggesting that MdAAT2 may use medium-chain fatty acyl CoA and benzoyl-CoA as acyl donors together with methanol acceptors as substrates. Surprisingly, the concentrations of linalool were significantly increased in transgenic tobacco leaves, which may mediate the repellent effect on Myzus persicae (Sulzer) aphids. Using methyl jasmonate (MeJA) and wounding treatments, we found that MdAAT2 may substitute for the partial ability of MeJA to induce the production of linalool in transgenic plants. These data suggest that MdAAT2 may be involved in the response to the MeJA signal and may play a role in the response to biotic and abiotic stress. [source] Disease stress-inducible genes of tobacco: expression profile of elicitor-responsive genes isolated by subtractive hybridizationPHYSIOLOGIA PLANTARUM, Issue 4 2003Daigo Takemoto In order to investigate the change in mRNA profile during tobacco disease response, a subtractive hybridization procedure was used to generate a cDNA library for genes induced in tobacco (Nicotiana tabacum cv. Samsun NN) treated with oomycete elicitor. Database searches with the randomly isolated genes revealed that this cDNA library was enriched for reported disease stress-responsive genes such as pathogenesis-related proteins and cell wall protein genes. The expressions of eight newly isolated genes were induced by inoculation with the non-pathogenic bacteria, Pseudomonas syringae pv. glycinea. The NtEIGs (N.tabacumelicitor- inducible genes) showed similarity to genes for stellacyanin-like protein (NtEIG-A1), glutathione peroxidase (NtEIG-C08), extensin-like protein (NtEIG-C29), WRKY transcription factor (NtEIG-D48), glycine rich protein (NtEIG-E17), , -1, 3-glucanase-like protein (NtEIG-E76), photoassimilate-responsive protein-1 (NtEIG-E80) and wound-induced protein (NtEIG-D10). The expression patterns of NtEIGs in tobacco leaf in response to P. syringae pv. glycinea, salicylic acid (SA), methyl jasmonate (MeJA) and wound stress were analysed. The individual expression patterns of NtEIGs indicate that the transcriptional activation of NtEIGs is regulated by various signals and the products of NtEIGs are involved in different processes at different stages of the plant defence responses. [source] Phylogenetic and transcriptional analysis of a strictosidine synthase-like gene family in Arabidopsis thaliana reveals involvement in plant defence responsesPLANT BIOLOGY, Issue 1 2009M. M. Sohani Abstract Protein domains with similarity to plant strictosidine synthase-like (SSL) sequences have been uncovered in the genomes of all multicellular organisms sequenced so far and are known to play a role in animal immune responses. Among several distinct groups of Arabidopsis thaliana SSL sequences, four genes (AtSSL4,AtSSL7) arranged in tandem on chromosome 3 show more similarity to SSL genes from Drosophila melanogaster and Caenorhabditis elegans than to other Arabidopsis SSL genes. To examine whether any of the four AtSSL genes are immune-inducible, we analysed the expression of each of the four AtSSL genes after exposure to microbial pathogens, wounding and plant defence elicitors using real-time quantitative RT-PCR, Northern blot hybridisation and Western blot analysis with antibodies raised against recombinant AtSSL proteins. While the AtSSL4 gene was constitutively expressed and not significantly induced by any treatment, the other three AtSSL genes were induced to various degrees by plant defence signalling compounds, such as salicylic acid, methyl jasmonate and ethylene, as well as by wounding and exposure to the plant pathogens Alternaria brassicicola and cucumber mosaic virus. Our data demonstrate that the four SSL-coding genes are regulated individually, suggesting specific roles in basal (SSL4) and inducible (SSL5-7) plant defence mechanisms. [source] Functional analysis of rice NPR1 -like genes reveals that OsNPR1/NH1 is the rice orthologue conferring disease resistance with enhanced herbivore susceptibility,PLANT BIOTECHNOLOGY JOURNAL, Issue 2 2007Yuexing Yuan Summary The key regulator of salicylic acid (SA)-mediated resistance, NPR1, is functionally conserved in diverse plant species, including rice (Oryza sativa L.). Investigation in depth is needed to provide an understanding of NPR1 -mediated resistance and a practical strategy for the improvement of disease resistance in the model crop rice. The rice genome contains five NPR1 -like genes. In our study, three rice homologous genes, OsNPR1/NH1, OsNPR2/NH2 and OsNPR3, were found to be induced by rice bacterial blight Xanthomonas oryzae pv. oryzae and rice blast Magnaporthe grisea, and the defence molecules benzothiadiazole, methyl jasmonate and ethylene. We confirmed that OsNPR1 is the rice orthologue by complementing the Arabidopsis npr1 mutant. Over-expression of OsNPR1 conferred disease resistance to bacterial blight, but also enhanced herbivore susceptibility in transgenic plants. The OsNPR1-green fluorescent protein (GFP) fusion protein was localized in the cytoplasm and moved into the nucleus after redox change. Mutations in its conserved cysteine residues led to the constitutive localization of OsNPR1(2CA)-GFP in the nucleus and also abolished herbivore hypersensitivity in transgenic rice. Different subcellular localizations of OsNPR1 antagonistically regulated SA- and jasmonic acid (JA)-responsive genes, but not SA and JA levels, indicating that OsNPR1 might mediate antagonistic cross-talk between the SA- and JA-dependent pathways in rice. This study demonstrates that rice has evolved an SA-mediated systemic acquired resistance similar to that in Arabidopsis, and also provides a practical approach for the improvement of disease resistance without the penalty of decreased herbivore resistance in rice. [source] No interaction between methyl jasmonate and ozone in Pima cotton: growth and allocation respond independently to bothPLANT CELL & ENVIRONMENT, Issue 5 2010D. A. GRANTZ ABSTRACT Ozone (O3) is damaging to plants, inducing signalling pathways involving antagonism between jasmonates and ethylene. These pathways mediate O3 responses, particularly to acute exposure, and their manipulation protected several species against acute and chronic O3. We use chronic daily exposure of up to 163 ppb O3, and twice weekly application of up to 320 µg plant,1 methyl jasmonate (MeJA) to test two hypothesizes: 1) a low rate of MeJA does not affect growth but increases O3 sensitivity; 2) a high rate inhibits growth but reduces O3 sensitivity. Both hypotheses were rejected. Growth declined with increases in both MeJA and O3. MeJA at 40 µg plant,1 caused no direct effect, and at 160 µg plant,1 reduced growth similarly at all O3. Neither rate altered O3 sensitivity. These additive responses are not consistent with protection by MeJA in this system. They may reflect inter-specific differences in signalling, since O3 concentrations used here exceeded some reported acute exposures. Alternatively, parallel responses to O3 and MeJA may suggest that O3 -induced jasmonates play a developmental role in chronic response but no protective role in the absence of lesions characteristic of acute exposure. MeJA appears useful as a probe of these mechanisms. [source] Root growth dynamics of Nicotiana attenuata seedlings are affected by simulated herbivore attackPLANT CELL & ENVIRONMENT, Issue 10 2007GRÉGOIRE M. HUMMEL ABSTRACT Many studies demonstrate resource-based trade-offs between growth and defence on a large timescale. Yet, the short-term dynamics of this growth reaction are still completely unclear, making it difficult to explain growth-defence trade-offs mechanistically. In this study, image-based non-destructive methods were used to quantify root growth reactions happening within hours following simulated herbivore attack. The induction of wound reactions in Nicotiana attenuata in the seedling stage led to transiently decreased root growth rates. Application of the oral secretion of the specialist herbivore Manduca sexta to the leaves led to a transient decrease in root growth that was more pronounced than if a mere mechanical wounding was imposed. Root growth reduction was more pronounced than leaf growth reduction. When fatty acid,amino acid conjugates (FACs) were applied to wounds, root growth reduction occurred in the same intensity as when oral secretion was applied. Timing of the transient growth reduction coincided with endogenous bursts of jasmonate (JA) and ethylene emissions reported in literature. Simulation of a wound response by applying methyl jasmonate (MeJA) led to more prolonged negative effects on root growth. Increased nicotine concentrations, trichome lengths and densities were observed within 72 h in seedlings that were treated with MeJA or that were mechanically wounded. Overall, these reactions indicate that even in a very early developmental stage, the diversion of plant metabolism from primary (growth-sustaining) to secondary (defence-related) metabolism can cause profound alterations of plant growth performance. [source] Effect of the plant peptide regulator, phytosulfokine-,, on the growth and Taxol production from Taxus sp. suspension culturesBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2006Beum Jun Kim Abstract Phytosulfokine-, (PSK-,) is a small plant peptide (5 amino acids) that displays characteristics typically associated with animal peptide hormones. PSK-, was originally isolated based on its mitogenic activity with plant cultures; it has been reported to increase production of tropane alkaloids from Atropa belladonna, although its general influence on secondary metabolite production is unknown. The studies reported in this article were initiated to evaluate the effects of PSK-, supplementation on production of TaxolÔ (paclitaxel) from plant cell cultures of Taxus sp. particularly when methyl jasmonate (MeJA) is added as an elicitor of secondary metabolism. The response to PSK-, supplementation was cell line dependent. Taxus cuspidata P93AF showed no statistically significant response to PSK-, supplementation while Taxus canadensis C93AD and T. cuspidata PO93X displayed a concentration-dependent response (up to 100 nM PSK-, added in first 24 h of culture) with a decrease in initial growth rate, an increase in cell density (dry weight/fresh weight), and increased Taxol production. More remarkably with T. canadensis (C93AD), a very strong synergistic response of PSK-, (100 nM) and methyl jasmonate (MeJA, 100 µM) elicitation was observed, resulting in Taxol level of 35.3,±,2.1 mg/L or 1.83,±,0.02 mg Taxol/g dry cell weight achieved at day 21, a level of approximately 10-fold higher than for either treatment by itself. Although the level of Taxol production achieved is not remarkable, this synergistic treatment was able to partially revive taxane production in cultures that have lost productivity due to extended time (over 10 years) in continuous subculture. © 2006 Wiley Periodicals, Inc. [source] Assessing the limitations to terpenoid indole alkaloid biosynthesis in Catharanthus roseus hairy root cultures through gene expression profiling and precursor feedingBIOTECHNOLOGY PROGRESS, Issue 5 2009Sheba Goklany Abstract The production of pharmaceutically important terpenoid indole alkaloids (TIAs) from Catharanthus roseus is partly regulated at the transcriptional level. In this study, limitations in TIA biosynthesis from C. roseus hairy root cultures were assessed through gene expression profiling and precursor feeding. The transcript levels of key TIA pathway genes (G10h, Tdc, Str, and Sgd) and metabolite levels associated with the TIA pathway (tryptamine, loganin, secologanin, strictosidine, ajmalicine, serpentine, and tabersonine) were monitored using quantitative RT-PCR and HPLC, respectively. In cultures elicited with methyl jasmonate (250 ,M MeJA on day 21), G10h, Tdc, Str, and Sgd expression increased by 9.1, 3.1, 6.7, and 8.3-fold, respectively, after 24 h. Up-regulation of gene expression was followed by a 160, 440, and 420% increase in strictosidine, ajmalicine, and tabersonine levels, respectively, after 5 days. Precursors loganin, tryptamine, or their combination were fed to noninduced and MeJA-induced cultures to complement the above studies. TIA production was not significantly enhanced in either noninduced or MeJA-induced cultures with precursor feeding. In noninduced cells, steps downstream of loganin and tryptamine were limiting (SLS, STR, or SGD) because either loganin or tryptamine accumulated in the cells with precursor feeding. These bottlenecks were partly overcome in MeJA-induced cultures as the expression of Str and Sgd genes and TIA production increased. However, secologanin accumulated in MeJA-induced cultures with precursor feeding, suggesting that STR was likely limiting under MeJA-induced conditions. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] | ||||||||||||||||||||||||||||