methyl-jasmonate and coronatine

Jasmonic acid (JA) regulates plant growth, development and stress responses. Coronatine insensitive 1 (COI1) and jasmonate zinc-finger inflorescence meristem-domain (JAZ) proteins form a receptor complex for jasmonoyl-l-isoleucine, a biologically active form of JA. Three COIs (OsCOI1a, OsCOI1b and OsCOI2) are encoded in the rice genome. In the present study, we generated mutants for each rice COI gene using genome editing to reveal the physiological functions of the three rice COIs. The oscoi2 mutants, but not the oscoi1a and oscoi1b mutants, exhibited severely low fertility, indicating the crucial role of OsCOI2 in rice fertility. Transcriptomic analysis revealed that the transcriptional changes after methyl jasmonate (MeJA) treatment were moderate in the leaves of oscoi2 mutants compared to those in the wild type or oscoi1a and oscoi1b mutants. MeJA-induced chlorophyll degradation and accumulation of antimicrobial secondary metabolites were suppressed in oscoi2 mutants. These results indicate that OsCOI2 plays a central role in JA response in rice leaves. In contrast, the assessment of growth inhibition upon exogenous application of JA to seedlings of each mutant revealed that rice COIs are redundantly involved in shoot growth, whereas OsCOI2 plays a primary role in root growth. In addition, a co-immunoprecipitation assay showed that OsJAZ2 and OsJAZ5 containing divergent Jas motifs physically interacted only with OsCOI2, whereas OsJAZ4 with a canonical Jas motif interacts with all three rice COIs. The present study demonstrated the functional diversity of rice COIs, thereby providing clues to the mechanisms regulating the various physiological functions of JA.

Topics: Arabidopsis; Arabidopsis Proteins; Cyclopentanes; Gene Editing; Gene Expression Regulation, Plant; Oryza; Oxylipins

Elicited broccoli suspension-cultured cells (SCC) provide a useful system for obtaining bioactive compounds, including glucosinolates (GS) and phenolic compounds (PCs). In this work, coronatine (Cor) and methyl jasmonate (MJ) were used to increase the bioactive compound production in broccoli SCC. Although the use of Cor and MJ in secondary metabolite production has already been described, information concerning how elicitors affect cell metabolism is scarce. It has been suggested that Cor and MJ trigger defence reactions affecting the antioxidative metabolism. In the current study, the concentration of 0.5 μM Cor was the most effective treatment for increasing both the total antioxidant capacity (measured as ferulic acid equivalents) and glucosinolate content in broccoli SCC. The elicited broccoli SCC also showed higher polyphenol oxidase activity than the control cells. Elicitation altered the antioxidative metabolism of broccoli SCC, which displayed biochemical changes in antioxidant enzymes, a decrease in the glutathione redox state and an increase in lipid peroxidation levels. Furthermore, we studied the effect of elicitation on the protein profile and observed an induction of defence-related proteins. All of these findings suggest that elicitation not only increases bioactive compound production, but it also leads to mild oxidative stress in broccoli SCC that could be an important factor triggering the production of these compounds.

Topics: Acetates; Amino Acids; Antioxidants; Brassica; Coumaric Acids; Cyclopentanes; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Glucosinolates; Glutathione; Indenes; Lipid Peroxidation; Oxylipins; Phytochemicals; Plant Cells; Plant Growth Regulators

Transcriptional activation of genes belonging to the plastidial MEP-derived isoprenoid pathway by elicitation with methyl jasmonate and coronatine enhanced the content of bioactive abietane diterpenes in Salvia sclarea hairy roots. We have shown that aethiopinone, an abietane diterpene synthesized in Salvia sclarea roots is cytotoxic and induces apoptosis in human melanoma cells. To develop a production platform for this compound and other abietane diterpenes, hairy root technology was combined with the elicitation of methyl jasmonate (MeJA) or the phytotoxin coronatine (Cor). Both MeJA and Cor induced a significant accumulation of aethiopinone, but prolonged exposure to MeJA irremediably caused inhibition of hairy root growth, which was unaffected by Cor treatment. Considering together the fold increase in aethiopinone content and the final hairy root biomass, the best combination was a Cor treatment for 28 days, which allowed to obtain up to 105.34 ± 2.30 mg L

Topics: Abietanes; Acetates; Amino Acids; Biomass; Cyclopentanes; Gene Expression Profiling; Gene Expression Regulation, Plant; Indenes; Naphthoquinones; Oxylipins; Plant Roots; RNA, Messenger; Salvia; Transcription, Genetic

Jasmonic acid (JA) signaling pathway in plants is activated against various developmental processes as well as biotic and abiotic stresses. The Jasmonate ZIM-domain (JAZ) protein family, the key regulator of plant JA signaling pathway, also participates in phytohormone crosstalk. This is the first study revealing the in vivo interactions of finger millet (Eleusine coracana (L.) Gaertn.) JAZ protein (EcJAZ) under methyl jasmonate (MJ) treatment. The aim of the study was to explore not only the JA signaling pathway but also the phytohormone signaling crosstalk of finger millet, a highly important future crop. From the MJ-treated finger millet seedlings, the EcJAZ interacting proteins were purified by affinity chromatography with the EcJAZ-matrix. Twenty-one proteins of varying functionalities were successfully identified by MALDI-TOF-TOF Mass spectrometry. Apart from the previously identified JAZ binding proteins, most prominently, EcJAZ was found to interact with transcription factors like NAC, GATA and also with Cold responsive protein (COR), etc. that might have extended the range of functionalities of JAZ proteins. Moreover, to evaluate the interactions of EcJAZ in the JA-co-receptor complex, we generated ten in-silico models containing the EcJAZ degron and the COI1-SKP1 of five monocot cereals viz., rice, wheat, maize, Sorghum and Setaria with JA-Ile or coronatine. Our results indicated that the EcJAZ protein of finger millet could act as the signaling hub for the JA and other phytohormone signaling pathways, in response to a diverse set of stressors and developmental cues to provide survival fitness to the plant.

Topics: Acetates; Amino Acids; Arabidopsis Proteins; Computer Simulation; Cyclopentanes; Eleusine; Indenes; Models, Molecular; Oxylipins; Phosphates; Plant Proteins; Protein Conformation; Protein Interaction Maps; Proteomics; Recombinant Proteins; Repressor Proteins; Signal Transduction; Structural Homology, Protein

The growing demand for the antitumorous agent paclitaxel and the difficulty in increasing its production by genetic engineering has prompted a search for new sources of taxanes. It has been reported that taxanes can be extracted from the angiosperm Corylus avellana L. Our aim was to improve taxane production by scaling up the process from mL-level to benchtop bioreactors, optimizing culture conditions and comparing the effect of two elicitors, 1 μM coronatine (Cor) and 100 μM methyl jasmonate (MeJA). Orbitally shaken flask cultures achieved a maximum fresh cell weight of 11.54 gDCW/L under control conditions, and MeJA- and Cor-treatment produced a statistically significant reduction in growth to 4.28 gDCW/L and 5.69 gDCW/L, while increasing the taxane content 3- and 27-fold, respectively. The enhancing effect of these elicitors on taxane production, despite affecting growth, was confirmed in orbitally shaken TubeSpin Bioreactors 50, where the highest taxane content (8583.3 μg/L) was obtained when 1μM Cor was used and elicitation took place at a packed cell volume of 50%. Two benchtop stirred bioreactors, BIOSTAT B plus and UniVessel SU, were compared, the latter providing a higher biomass of C. avellana cell suspension cultures. Transferring the established optimum culture conditions for taxane production to the UniVessel SU resulted in a total taxane content of 6246.1 μg/L, a 10-fold increase compared with shake flask experiments.

Topics: Acetates; Alkaloids; Amino Acids; Antineoplastic Agents; Biomass; Bioreactors; Cell Culture Techniques; Cell Proliferation; Cell Survival; Cells, Cultured; Corylus; Cyclopentanes; Indenes; Oxylipins; Paclitaxel; Plant Growth Regulators; Taxoids

Jasmonic acid and its derivatives (jasmonates [JAs]) play central roles in floral development and maturation. The binding of jasmonoyl-L-isoleucine (JA-Ile) to the F-box of CORONATINE INSENSITIVE1 (COI1) is required for many JA-dependent physiological responses, but its role in anthesis and pollinator attraction traits remains largely unexplored. Here, we used the wild tobacco Nicotiana attenuata, which develops sympetalous flowers with complex pollination biology, to examine the coordinating function of JA homeostasis in the distinct metabolic processes that underlie flower maturation, opening, and advertisement to pollinators. From combined transcriptomic, targeted metabolic, and allometric analyses of transgenic N. attenuata plants for which signaling deficiencies were complemented with methyl jasmonate, JA-Ile, and its functional homolog, coronatine (COR), we demonstrate that (1) JA-Ile/COR-based signaling regulates corolla limb opening and a JA-negative feedback loop; (2) production of floral volatiles (night emissions of benzylacetone) and nectar requires JA-Ile/COR perception through COI1; and (3) limb expansion involves JA-Ile-induced changes in limb fresh mass and carbohydrate metabolism. These findings demonstrate a master regulatory function of the JA-Ile/COI1 duet for the main function of a sympetalous corolla, that of advertising for and rewarding pollinator services. Flower opening, by contrast, requires JA-Ile signaling-dependent changes in primary metabolism, which are not compromised in the COI1-silenced RNA interference line used in this study.

Topics: Abscisic Acid; Acetates; Acetone; Amino Acids; Animals; Arabidopsis Proteins; Cyclopentanes; Esterases; Flowers; Gene Expression Profiling; Gene Expression Regulation, Plant; Indenes; Isoleucine; Manduca; Metabolic Networks and Pathways; Methyltransferases; Models, Biological; Nicotiana; Oligonucleotide Array Sequence Analysis; Oxylipins; Plant Growth Regulators; Plant Nectar; Plant Proteins; Plants, Genetically Modified; Pollination; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference

Coronatine is a toxin produced by the pathogen Pseudomonas syringae. This compound has received much attention recently for its potential to act as a plant growth regulator and elicitor of plant secondary metabolism. To gain more insight into the mechanism by which elicitors can affect the biosynthesis of paclitaxel (Px) and related taxanes, the effect of coronatine (Cor) and methyl jasmonate (MeJA) on Taxus media cell cultures has been studied. For this study, a two-stage cell culture was established, in which cells were first cultured for 14 days in a medium optimised for growth, after which the cells were transferred to medium optimised for secondary metabolite production. The two elicitors were added to the medium at the beginning of the second stage. Total taxane production in the cell suspension was significantly enhanced by both elicitors, increasing from a maximum level of 8.14mg/L in control conditions to 21.48mg/L (day 12) with MeJA and 77.46mg/L (day 16) with Cor. Expression analysis indicated that the txs, t13oh, t2oh, t7oh, dbat, pam, bata and dbtnbt genes were variably induced by the presence of the elicitors. Genes encoding enzymes involved in the formation of the polihydroxylated hypothetical intermediate (TXS, T13OH, T2OH, T7OH) and the phenylalanoil CoA chain (PAM) were stronger induced than those encoding enzymes catalysing the last steps of the Px biosynthetic pathway (DBAT, BAPT and DBTNBT). Notably, although taxane accumulation differed qualitatively and quantitatively following MeJA- or Cor-elicitation, gene expression induction patterns were similar, inferring that both elicitors may involve distinct but yet uncharacterised regulatory mechanisms.

Topics: Acetates; Amino Acids; Cells, Cultured; Cyclopentanes; Gene Expression Regulation, Plant; Genes, Plant; Indenes; Oxylipins; Plant Growth Regulators; Taxoids; Taxus

Jasmonates (JAs) regulate various stress responses and development processes in plants, and the JA pathway is tightly controlled. In this study, we report the functional characterization of two novel RING-type ubiquitin ligases, RING DOMAIN LIGASE3 (RGLG3) and RGLG4, in modulating JA signaling. Both RGLG3 and RGLG4 possessed ubiquitin ligase activities and were widely distributed in Arabidopsis (Arabidopsis thaliana) tissues. Altered expression of RGLG3 and RGLG4 affected methyl JA-inhibited root growth and JA-inductive gene expression, which could be suppressed by the coronatine insensitive1 (coi1) mutant. rglg3 rglg4 also attenuated the inhibitory effect of JA-isoleucine-mimicking coronatine on root elongation, and consistently, rglg3 rglg4 was resistant to the coronatine-secreting pathogen Pseudomonas syringae pv tomato DC3000, suggesting that RGLG3 and RGLG4 acted in response to the coronatine and promoted JA-mediated pathogen susceptibility. In addition, rglg3 rglg4 repressed wound-stunted plant growth, wound-stimulated expression of JA-responsive genes, and wound-induced JA biosynthesis, indicating their roles in JA-dependent wound response. Furthermore, both RGLG3 and RGLG4 responded to methyl JA, P. syringae pv tomato DC3000, and wounding in a COI1-dependent manner. Taken together, these results indicate that the ubiquitin ligases RGLG3 and RGLG4 are essential upstream modulators of JA signaling in response to various stimuli.

Topics: Acetates; Amino Acids; Arabidopsis; Arabidopsis Proteins; Bacterial Proteins; Cyclopentanes; Enzyme Activation; Feedback, Physiological; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Genes, Plant; Indenes; Oxylipins; Phylogeny; Plant Diseases; Plant Immunity; Plant Roots; Plants, Genetically Modified; Pseudomonas syringae; Recombinant Proteins; Signal Transduction; Ubiquitin-Protein Ligases; Ubiquitination

Jasmonic acid (JA) is a crucial plant defence signalling substance that has recently been shown to mediate herbivory-induced root growth reduction in the ecological model species Nicotiana attenuata. To clarify whether JA-induced reduction of root growth might be a general response increasing plant fitness under biotic stress, a suite of experiments was performed with the model plant Arabidopsis thaliana. JA bursts were elicited in leaves of A. thaliana in different ways. Root growth reduction was neither induced by foliar application of herbivore oral secretions nor by direct application of methyl jasmonate to leaves. Root growth reduction was observed when leaves were infected with the pathogen Pseudomonas syringae pv. tomato, which persistently induces the JA signalling pathway. Yet, high resolution growth analyses of this effect in wild type and JA biosynthesis knock-out mutants showed that it was elicited by the bacterial toxin coronatine that suggests ethylene- but not JA-induced root growth reduction in A. thaliana. Overall, the results demonstrate that the reaction of root growth to herbivore-induced JA signalling differs among species, which is discussed in the context of different ecological defence strategies among species.

Topics: Acetates; Amino Acids; Animals; Arabidopsis; Cyclopentanes; Cyclopropanes; Ethylenes; Gene Knockout Techniques; Indenes; Oxylipins; Plant Leaves; Plant Roots; Pseudomonas syringae; Signal Transduction; Spodoptera

Coronatine (COR) is a phytotoxin produced by several pathovars of Pseudomonas syringae and consists of coronafacic acid (CFA), an analog of methyl jasmonic acid (MeJA), and coronamic acid (CMA), which resembles 1-aminocyclopropane-1-carboxylic acid (ACC), a precursor to ethylene. An understanding of how COR functions, is perceived by different plant tissues, and the extent to which it mimics MeJA remain unclear. In this study, COR and related compounds were examined with respect to structure and function. The results indicate that conjugation of CFA to an amino acid is required for optimal activity in tomato, including chlorosis, changes in chloroplast structure, cell wall thickening, accumulation of proteinase inhibitors, induction of anthocyanins, and root growth inhibition. cDNA microarrays were utilized to understand the molecular processes that are regulated by MeJA, COR, CFA and CMA in tomato leaves. A comparison of COR- and MeJA-regulated transcriptomes revealed that COR regulated 35% of the MeJA-induced genes. There was significant overlap in the number of COR and CFA-regulated genes with CFA impacting the expression of 39.4% of the COR-regulated genes. Taken together, the results of biological assays, ultrastructural studies, and gene expression profiling demonstrate that: (1) the intact COR molecule impacts signaling in tomato via the jasmonic acid, ethylene, and auxin pathways; (2) CMA does not function as a structural analog of ACC; (3) COR has a broader range of functions than either CFA or CMA; and (4) COR and MeJA share similar, but not identical activities and impact multiple phytohormone pathways in tomato.

Topics: Acetates; Amino Acids; Bacterial Toxins; Cyclopentanes; Gene Expression Regulation, Plant; Indenes; Molecular Structure; Oxylipins; Plant Growth Regulators; Plant Leaves; Plant Roots; Seedlings; Signal Transduction; Solanum lycopersicum

Oxylipins of the jasmonate pathway and synthetic functional analogs have been analyzed for their elicitor-like activities in an assay based on the induced accumulation of glyceollins, the phytoalexins of soybean (Glycine max L.), in cell suspension cultures of this plant. Jasmonic acid (JA) and its methyl ester showed weak phytoalexin-inducing activity when compared to an early jasmonate biosynthetic precursor, 12-oxo-phytodienoic acid (OPDA), as well as to the bacterial phytotoxin coronatine and certain 6-substituted indanoyl-L-isoleucine methyl esters, which all were highly active. Interestingly, different octadecanoids and indanoyl conjugates induced the accumulation of transcripts of various defense-related genes to different degrees, indicating distinct induction competencies. Therefore, these signaling compounds and mimics were further analyzed for their effects on signal transduction elements, such as the transient enhancement of the cytosolic Ca2+ concentration and MAP kinase activation, which are known to be initiated by a soybean pathogen-derived beta-glucan elicitor. In contrast to the beta-glucan elicitor, none of the other compounds tested triggered these early signaling elements. Moreover, endogenous levels of OPDA and JA in soybean cells were shown to be unaffected after treatment with beta-glucans. Thus, OPDA and JA, which are functionally mimicked by coronatine and a variety of 6-substituted derivatives of indanoyl-L-isoleucine methyl ester, represent highly efficient signaling compounds of a lipid-based pathway not deployed in the beta-glucan elicitor-initiated signal transduction.

Topics: Acetates; Amino Acids; Benzopyrans; Cyclopentanes; Fatty Acids, Unsaturated; Gene Expression Regulation, Plant; Glycine max; Indenes; Mitogen-Activated Protein Kinases; Molecular Mimicry; Oxylipins; Plant Growth Regulators; Pterocarpans; RNA, Messenger; Signal Transduction

Similar to the prostanoid-mediated inflammatory response in mammals, jasmonate-mediated wound response in plant leaves is inhibited by salicylic acid (SA) or acetylsalicylate (aspirin). In tobacco BY-2 cells, expression of the gene for ornithine decarboxylase (ODC) involved in putrescine synthesis is rapidly inducible by methyl jasmonate (MeJA). A nuclear gene for ODC isolated from tobacco, gNtODC-1, was an intron-less gene and MeJA induced the expression of a GUS fusion gene with the gNtODC-1 promoter in transformed tobacco cells. Although SA alone did not induce the expression, 0.2 to 20 microM SA increased the MeJA-induced expression of the fusion gene to about two-fold. A similar increase was observed with aspirin but not with 3- or 4-hydroxybenzoic acids. SA at concentrations up to 200 microM did not inhibit the MeJA-induction of mRNAs for the GUS fusion gene and the endogenous gene for ODC.

Topics: Acetates; Amino Acids; Aspirin; Bacterial Toxins; Cells, Cultured; Cloning, Molecular; Cyclopentanes; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Indenes; Molecular Sequence Data; Nicotiana; Ornithine Decarboxylase; Oxylipins; Plants, Toxic; Salicylic Acid

In tobacco plants, wounding induces production of a set of defense-related proteins such as basic pathogenesis-related (PR) proteins and proteinase inhibitors (PIs) via the jasmonate/ethylene pathway. Although class III plant peroxidase (POX) is also wound-inducible, the regulatory mechanism for its wound-induced expression is not fully understood. Here, we describe that a tobacco POX gene (tpoxN1), which is constitutively expressed in roots, is induced locally 30 min after wounding and then systemically in tobacco plants. Infection of necrotizing virus also induced tpoxN1 gene. The wound-induced expression was not enhanced by known wound-signal compounds such as methyl jasmonate (MeJA) and ethephon in contrast to other wound-inducible genes such as basic PR-1 and PI-II genes. And treatment with MeJA and coronatine, biological analogs of jasmonate, rather suppressed the tpoxN1 expression. Salicylic acid, an antagonist of jasmonate-based wound signaling, did not suppress the wound-induced expression of tpoxN1. Only spermine, which is reported as an endogenous inducer for acidic PR genes in tobacco mosaic virus-infected tobacco leaves, could induce tpoxN1 gene expression. These results suggest that wound-induced expression of the tpoxN1 gene is regulated differently from that of the basic PR and PI-II genes.

Topics: Acetates; Amino Acids; Cyclopentanes; Enzyme Induction; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Indenes; Nicotiana; Organophosphorus Compounds; Oxylipins; Peroxidase; Plant Growth Regulators; Plants, Toxic; Tobacco Mosaic Virus

Coronatine is a phytotoxin produced by some plant-pathogenic bacteria. It has been shown that coronatine mimics the action of methyl jasmonate (MeJA) in plants. MeJA is a plant-signaling molecule involved in stress responses such as wounding and pathogen attack. In Arabidopsis thaliana, MeJA is essential for pollen grain development. The coi1 (for coronatine-insensitive) mutant of Arabidopsis, which is insensitive to coronatine and MeJA, produces sterile male flowers and shows an altered response to wounding. When the differential display technique was used, a message that was rapidly induced by coronatine in wild-type plants but not in coi1 was identified and the corresponding cDNA was cloned. The coronatine-induced gene ATHCOR1 (for A. thaliana coronatine-induced) is expressed in seedlings, mature leaves, flowers, and siliques but was not detected in roots. The expression of this gene was dramatically reduced in coi1 plants, indicating that COI1 affects its expression. ATHCOR1 was rapidly induced by MeJA and wounding in wild-type plants. The sequence of ATHCOR1 shows no strong homology to known proteins. However, the predicted polypeptide contains a conserved amino acid sequence present in several bacterial, animal, and plant hydrolases and includes a potential ATP/GTP-binding-site motif (P-loop).

Topics: Acetates; Amino Acid Sequence; Amino Acids; Arabidopsis; Arabidopsis Proteins; Base Sequence; Cloning, Molecular; Cyclopentanes; Drug Resistance; Gene Expression Regulation, Plant; Genes, Plant; Heat-Shock Proteins; Indenes; Molecular Sequence Data; Mutation; Oxylipins; Plant Proteins

The phytotoxin coronatine and the plant growth regulator methyl jasmonate (MeJA) inhibit the growth of Arabidopsis seedlings. Coronatine and MeJA induced the accumulation of an approximately 29-kD protein in wild-type seedlings but not in seedlings of the coi1 mutant, which is insensitive to both compounds. The approximately 29-kD protein was recognized not only by antibodies raised against the partially purified polypeptide, but also by antibodies raised against vegetative storage proteins (VSPs) from soybean (29 kD) and poplar (32 kD). In the absence of added MeJA/coronatine, the VSP-like protein was highly expressed in flowers and siliques but not in seeds, seedlings, or mature leaves of wild-type Arabidopsis. By contrast, this protein could not be detected in coi1 seedlings treated with coronatine or MeJA, and it was found in very low levels in the male sterile flowers of coi1. A transcript corresponding to the gene of the Arabidopsis 27-kD VSP precursor shows the same pattern of expression as the VSP-like protein. Significantly, the VSP-like protein was not detected in green siliques or seeds obtained from coi1 flowers fertilized with wild-type pollen. We conclude that the VSP-like protein is normally expressed in maternal tissues, where it is regulated by COI1, but is not essential for the development of siliques.

Topics: Acetates; Amino Acids; Arabidopsis; Base Sequence; Cyclopentanes; DNA Primers; Gene Expression; Genes, Plant; Indenes; Molecular Sequence Data; Oxylipins; Plant Proteins; Polymerase Chain Reaction; RNA, Messenger; RNA, Plant; Seeds; Transcription, Genetic