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The increase in demand for natural rubber has led to the search for alternative sources. Lactuca serriola is emerging as a promising candidate, as the quality of the natural rubber it produces is comparable to that of the Pará Rubber Plant, Hevea brasiliensis. This study examines the effect of methyl jasmonate (MeJA), a known elicitor, on the expression of key rubber biosynthesis pathway genes (HMGR1, HMGS1, CPT2, and SRPP1) in the latex of L. serriola plants. The expression levels of these genes increased significantly after the foliar application of 200 and 400 µM MeJA. The highest relative expression level for HMGR1, HMGS1, CPT2 and SRPP1 was 3.74, 18.56, 11.91and 16.59 fold respectively. Furthermore, the rubber content in L. serriola showed a significant rise post-treatment compared to the control with increasing the level of MeJA (6.19%, 7.24% and 7.85% which correspond to 0, 200 and 400 µM). Gel permeation chromatography revealed an augmentation in the molecular weight of extracted natural rubber from treated plants. Samples treated with 400 µM of MeJA had the highest molecular weight (1570 kg mol−1) compared to control (1186 kg mol−1). This study has demonstrated that MeJA, through the regulation of rubber biosynthesis genes, is capable of enhancing the quality and quantity of natural rubber extracted from alternative sources, such as L. serriola. [ABSTRACT FROM AUTHOR]

In the present study, the effects of methyl jasmonate (MeJA) and silver nanoparticles (AgNPs) on Salvia nemorosa L. were evaluated under NaCl stress. To this end, total soluble sugar content, total phenolic and flavonoid contents, total antioxidant capacity, H2O2 content, photosynthetic pigment content, malondialdehyde (MDA) content, proline content, and enzymatic antioxidant activities were assessed. When the results for photosynthetic pigment content were evaluated, the highest levels of total carotenoid content, chlorophyll a, and chlorophyll b were obtained with NaCl + AgNP + MeJA treatment. Under NaCl stress, MDA and H2O2 levels increased, but they decreased when AgNP and MeJA were applied. All treatment groups had higher proline contents than the control group; the NaCl + AgNP + MeJA treatment group had the lowest content, while the NaCl treatment group had the highest. The combined elicitor treatment had little effect on total soluble sugar content. The combined elicitor treatment significantly increased total phenolic and flavonoid contents compared to separate applications. The most effective treatment for scavenging DPPH radicals was NaCl + MeJA, whereas the most effective treatment for scavenging CUPRAC and ABTS radicals was NaCl + MeJA + AgNP. Treatmentrelated variations were observed in enzyme activities; NaCl + MeJA + AgNP treatment caused the greatest increases in SOD, CAT, and APX activities, whereas NaCl + MeJA treatment resulted in the maximum GR activity. Compared to treatment with NaCl alone, the combined application of AgNP and MeJA improved some physiological and biochemical indices and increased plant resistance to salt stress. The synergistic impact of AgNP and MeJA on reducing the effects of salt stress in Salvia nemorosa L. suggests that these two compounds may strengthen plant resilience under adverse environmental conditions. [ABSTRACT FROM AUTHOR]

• Elicitors applied to Stevia activated enzymes and increased SGs. • SA was found to be the most effective treatment for increasing Reb A. • Elicitation impacted Stevia growth under SS, especially with Spd and SA combination. • The combination of MeJ + Spd was more effective in increasing stevioside content. Stevia rebaudiana Bertoni is a plant species with sweet-tasting leaves that can be used as a natural, low-calorie sweetener with potential health benefits. Salt stress can reduce plant growth and productivity, but the application of growth regulators like salicylic acid (SA), methyl jasmonate (MeJ), and spermidine (Spd) can manage various plant abiotic stresses and improve plant growth and productivity. In this work, we investigated the role of exogenous SA, MeJ, and Spd in conferring salt stress tolerance in Stevia by analyzing plant growth, chlorophyll (Chl), total phenolic, total carotenoid content, antioxidant defense system and steviol glycosides. The aim of a recent study was to assess the effects of these regulators on Stevia plants under both individual and combined salt stress conditions. Foliar application of these regulators improved plant growth under salt stress, with moderate salinity stress increasing glycoside compounds. SA was most effective in increasing rebaudioside A (Reb A), while MeJ + Spd combination was best for increasing stevioside (Stv) content. Individual applications of Spd, MeJ, and SA significantly impacted plant growth and antioxidant content, although their combined use was less effective. Spd application under salt stress yielded the highest increases in total carotenoid and Chl a content, while MeJ and Spd together significantly boosted Chl b content. The study found that SA enhanced superoxide dismutase (SOD) activity and reduced catalase (CAT) activity under salt stress, whereas MeJ alone increased both CAT and SOD activity. The distinct responses to Spd, SA, and MeJ suggest varied mechanisms in oxidative stress-induced antioxidant production. Overall, the use of these growth regulators can improve the growth, yield, and nutritional value of Stevia under salt stress, offering significant implications for agriculture and food security. [ABSTRACT FROM AUTHOR]

Elicitors can promote the production of important metabolites in the adventitial roots (ARs) cultures. This study assessed the effects of methyl jasmonate (MeJA) and salicylic acid (SA) on the levels of bioactive compounds, including the total flavonoid content (TFC), total phenolic content (TPC), and total cannabidiol (CBD) content, in AR cultures of Cannabis sativa L. The results indicated that MeJA and SA treatment resulted in the highest AR dry weight of 200 and 50 µM, respectively. Furthermore, MeJA and SA treatment increased the soluble sugar content (SSC), proline (Pro), and soluble protein content (SPC), as well as the activities of peroxidase (POD) and superoxide dismutase (SOD) in ARs. Moreover, the optimal MeJA and SA concentrations for enhancing TFC, TPC, and total CBD content were 200 and 50 μM, respectively, while the activities of phenylalanine ammonia-lyase (PAL) and prenyltransferase (PT) were also found to be highest at these concentrations. In addition, 50 μM SA was found to be more effective than 200 μM MeJA for increasing TFC, whereas for TPC, MeJA was more effective than SA; however, both elicitors were equally effective in enhancing the total CBD. In summary, this study investigated the effects of MeJA and SA as elicitors on AR cultures from C. sativa, providing new evidence for the synthesis of metabolites in vitro.Key Message: Methyl jasmonate and salicylic acid can be employed as elicitors to enhance the total flavonoid, total phenolic, and total CBD contents in AR cultures of C. sativa. [ABSTRACT FROM AUTHOR]

Dracocephalum polychaetum Bornm. has a narrow expanse of distribution, mostly centered in the mountainous terrain of Kerman, Iran. Due to the value of its phytochemical profile and secondary metabolites, the current research aimed to increase phytochemical compounds by the exogenous application of methyl jasmonate (MJ) at several concentrations (0, 10, 25, 50, and 100 µM) in vitro. After callus induction and cell suspension culture establishment, the cells of D. polychaetum were treated with various MJ concentrations in separate treatment groups. The content of phytochemical compounds was then analyzed using UV–Vis spectrophotometry and high-performance liquid chromatography (HPLC). The application of MJ imposed oxidative stress and alterations in fresh weight (FW). It also increased the activity of tyrosine ammonia lyase (TAL) and phenylalanine ammonia-lyase (PAL), leading to enhanced production of flavonol (TFL), total phenolic compounds (TPC), anthocyanin (Ant), flavonoid (TFD), H2O2, malondialdehyde (MDA) content, and total antioxidant capacity in all treated cells compared to the control cells. Furthermore, the levels of apigenin, rutin, rosmarinic acid, quercetin, syringic acid, chlorogenic acid, 4-hydroxybenzoic acid, ferulic acid, gallic acid, p-cumaric acid, and vanillic acid within the all treated cells changed significantly. These findings suggest that MJ, particularly at low concentrations, has the potential to enhance the production of phytochemical compounds in D. polychaetum.Key message: The cell suspension of D. polychaetum treated with Methyl Jasmonate is a helpful approach for improving synthesizing phenolic compounds under controlled and sterile conditions without genetic modifications. [ABSTRACT FROM AUTHOR]

AbstractCalendula officinalis is a widespread medicinal plant with a sufficiently well-studied chemical composition. Secondary metabolites synthesized by C.officinalis plants have pharmacological value for treating numerous diseases, and various types of aseptic in vitro cultures can be used as a source of these compounds. From this perspective, hairy roots attract considerable attention for the production of bioactive chemicals, including flavonoids with antioxidant activity. This paper shows the possibility of C.officinalis hairy roots obtaining with 100% frequency by Agrobacterium rhizogenes genetic transformation. Hairy root lines differed in growth rate and flavonoid content. In particular, flavonoids were accumulated in the amount of up to 6.68 ± 0.28 mg/g of wet weight. Methyl jasmonate in the concentration of 10 µM inhibited root growth to a small extent but stimulated the synthesis of flavonoids. The antioxidant activity and the reducing power increased in the roots grown in the medium with methyl jasmonate. The strong correlation of antioxidant activity and reducing power with flavonoid content was detected. The influence of extraction conditions on the content of flavonoids in the extracts and their bioactivity was determined. The potent reducing activity of extracts from hairy roots allowed the production of silver nanoparticles, which was confirmed by transmission electron microscopy. [ABSTRACT FROM AUTHOR]

Jasmonates, including jasmonic acid (JA) and its derivatives such as methyl jasmonate (MeJA) or jasmonly isoleucine (JA-Ile), regulate plant responses to various biotic and abiotic stresses. In this study, we applied exogenous MeJA onto Senna tora leaves subjected to wounding and conducted a transcriptome deep sequencing analysis at 1 (T1), 3 (T3), 6 (T6), and 24 (T24) h after MeJA induction, along with the pretreatment control at 0 h (T0). Out of 18,883 mapped genes, we identified 10,048 differentially expressed genes (DEGs) between the T0 time point and at least one of the four treatment times. We detected the most DEGs at T3, followed by T6, T1, and T24. We observed the upregulation of genes related to JA biosynthesis upon exogenous MeJA application. Similarly, transcript levels of genes related to flavonoid biosynthesis increased after MeJA application and tended to reach their maximum at T6. In agreement, the flavonols kaempferol and quercetin reached their highest accumulation at T24, whereas the levels of the anthraquinones aloe-emodin, emodin, and citreorosein remained constant until T24. This study highlights an increase in flavonoid biosynthesis following both MeJA application and mechanical wounding, whereas no significant influence is observed on anthraquinone biosynthesis. These results provide insights into the distinct regulatory pathways of flavonoid and anthraquinone biosynthesis in response to MeJA and mechanical wounding. [ABSTRACT FROM AUTHOR]

Self-incompatibility (SI) poses a significant reproductive barrier, severely impacting the yield, quality, and economic value of Camellia oleifera. In this study, methyl jasmonate (MeJA) was employed as an exogenous stimulus to alleviate SI in C. oleifera. The research findings revealed that an exogenous dose of 1000 μmol·L−1 MeJA enhanced the germination and tube growth of C. oleifera self-pollen and greatly improved ovule penetration (18.75%) and fertilization (15.81%), ultimately increasing fruit setting (18.67%). It was discovered by transcriptome analysis that the key genes (CAD, C4H) involved in the lignin production process exhibited elevated expression levels in self-pistils treated with MeJA. Further analysis showed that the lignin concentration in the MeJA-treated pistils was 31.70% higher compared with the control group. As verified by pollen germination assays in vitro, lignin in the appropriate concentration range could promote pollen tube growth. Gene expression network analysis indicated that transcription factor bHLH may be pivotal in regulating lignin biosynthesis in response to MeJA, which in turn affects pollen tubes. Further transient knockdown of bHLH (Co_33962) confirmed its important role in C. oleifera pollen tube growth. In summary, the application of MeJA resulted in the stimulation of self-pollen tube elongation and enhanced fruit setting in C. oleifera, which could be associated with the differential change in genes related to lignin synthesis and the increased lignin content. [ABSTRACT FROM AUTHOR]

BACKGROUND: Viticulture has adapted foliar applications of biostimulants as a tool to improve crop quality. Recently, nanotechnology has been incorporated as a strategy to reduce the loss of biostimulants and treat nutrient deficiencies. Therefore, the present study aimed to investigate the effect of foliar applications of amorphous calcium phosphate nanoparticles (ACP) doped with methyl jasmonate (ACP‐MeJA) and urea (ACP‐Ur), individually or together (ACP‐MeJA+Ur), on the content of volatile compounds in 'Tempranillo' grapes, compared to the conventional application of MeJA and Ur, individually or in combination (MeJA+Ur). RESULTS: The results showed that nanoparticle treatments reduced the total C6 compounds and some carbonyl compounds in the grape musts. This is of novel interest because their presence at high levels is undesirable to quality. In addition, some aroma‐positive compounds such as nerol, neral, geranyl acetone, β‐cyclocitral, β‐ionone, 2‐phenylethanal and 2‐phenylethanol increased, despite applying MeJA and Ur at a lower dose. CONCLUSION: Consequently, although few differences in grape volatile composition were detected, nanotechnology could be an option for improving the aromatic quality of grapes, at the same time as reducing the required doses of biostimulants and generating more sustainable agricultural practices. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This study investigates the responses of tea (Camellia sinensis) flower and leaf cell cultures to methyl jasmonate (MeJA) treatment, focusing particularly on mono- and sesquiterpenoid metabolism. Transcript profiling using cDNA-qRT PCR and targeted metabolite analysis revealed a notable increase in the production of mono- and sesquiterpenoids in MeJA-treated cultures compared to controls (untreated samples). Specifically, MeJA treatment (50, 100, and 150 µM) for varying durations (8, 16, and 24 h) stimulated the accumulation of mono- and sesquiterpenoid in both tissue types, with gene expression levels increasing by 5–17 folds for monoterpenoids and 5–15 folds for sesquiterpenoids respectively. Furthermore, a significant positive correlation (p < 0.05) was observed between gene expression and metabolite production following MeJA treatment in both leaf and flower samples. Our findings underscore the intricate interplay between MeJA signalling and secondary metabolism in tea cell cultures. This study contributes to the growing body of knowledge concerning MeJA-mediated responses in tea cell culture with practical implications in the food, cosmetic, and pharmaceutical industries.Key message: Methyl jasmonate (MeJA) treatment alters terpenoid synthesis in tea cell cultures, unveiling its regulatory influence on secondary metabolism. [ABSTRACT FROM AUTHOR]

The berries of Embelia ribes Burm f. are a rich source of embelin, a compound known for its anthelmintic, antidiabetic, and anticancer activities. Due to over-exploitation, the natural habitat of Embelia ribes is now considered vulnerable. Traditional propagation methods are insufficient to meet current demands, necessitating alternative production approaches. This study was designed to explore in vitro culture as a viable alternative for the production of embelin. Although numerous studies have focused on extracting embelin from callus cultures, research on enhancing the embelin content in both organogenic and embryogenic callus cultures remains limited. The objective of this study was to enhance embelin production in callus cultures by using both biotic and abiotic elicitors. Additionally, efforts were made to optimize rapid in vitro shoot induction. We achieved the best response rate for the induction of organogenic and embryogenic calli using MS basal medium supplemented with BAP and TDZ in combination with 2-4-D. Among the various elicitors tested, chitosan at 200 mg/L was the most effective, yielding the highest embelin content, at 6.44% in embryogenic calli and 5.72% in organogenic calli. Subsequent subculturing enabled successful differentiation of callus cultures into shoot buds on MS medium supplemented with a combination of BAP (6-benzylaminopurine) and IAA (indole-3-acetic acid) at concentrations of 2.0 mg/L and 0.1 mg/L, respectively. An effective protocol has been developed for obtaining the highest embelin content from embryogenic and organogenic callus cultures, coupled with a high frequency of shoot multiplication. The protocol can be instrumental for large-scale embelin production, ex-situ conservation, sustainable utilization, and industrial applications.Key message: Developed the first efficient protocol for enhancing embelin production in Embelia ribes through in vitro callus cultures, with chitosan as the most effective elicitor for large-scale production, ex-situ conservation, and sustainable use. [ABSTRACT FROM AUTHOR]

Taraxacum kok-saghyz Rodin (TKS) is a recognized alternative source of natural rubber comparable to the rubber tree. The geranylgeranyl pyrophosphate synthase (GGPS) catalyzed the synthesis of geranylgeranyl pyrophosphate (GGPP), which is an important enzyme in the secondary metabolism pathway. In this study, we present the first analysis of the GGPS gene family in TKS, where a total of seven TkGGPS family members were identified. Their core motifs, conserved structural domains, gene structures, and cis-acting elements were described. In addition, two phylogenetic trees were constructed based on the Neighbor-Joining and Maximum-Likelihood methods, and the TkGGPSs were highly conserved and exhibited good collinearity with the other species. Transcriptome data showed that seven TkGGPS gene members were expressed in all the 12 tissues measured, and TkGGPS1, TkGGPS3, and TkGGPS6 were highly expressed in latex, suggesting that they may be associated with natural rubber synthesis. Meanwhile, quantitative real-time PCR (qRT-PCR) showed that the expression levels of the TkGGPS genes were regulated by the ethylene and methyl jasmonate (MeJA) pathways. Subcellular localization results indicated that all the TkGGPS proteins were also located in chloroplasts involved in photosynthesis in plants. This study will provide valuable insights into the selection of candidate genes for molecular breeding and natural rubber biosynthesis in TKS. [ABSTRACT FROM AUTHOR]

Bananas are economically important fruits, but they are vulnerable to mechanical damage during harvesting and transport. This study examined the effects of methyl jasmonate (MeJA) on the cell membrane integrity and membrane lipid metabolism of wounded banana fruits after harvest. The results showed that 10 and 50 μM MeJA treatments on mechanically wounded bananas significantly delayed ripening and senescence in comparison with the control. At the end of storage, MeJA-treated groups showed a significant reduction in electrolyte leakage and malondialdehyde content, indicating that MeJA protected cell membrane integrity. MeJA also led to a significant decrease in the activity of antioxidant enzymes, including lipoxygenase, diacylglycerol kinase, and lipid phosphate phosphatase. Furthermore, MeJA reduced phospholipase (C and D), phosphatidic acid, and diacylglycerol levels, as well as slowed down the decrease in phosphatidylcholine and phosphatidylinositol contents. Compared to the control, MeJA significantly downregulated the expression of MaPLDγ, MaPLDα, and MaPLDζ. Therefore, MeJA treatment could be a reliable method to delay the senescence of harvested banana fruits subjected to mechanical wounding. [ABSTRACT FROM AUTHOR]

Heavy metal toxicity adversely affects plants by changing physiological, biochemical, and molecular mechanisms. Lead (Pb) is one of the most common heavy metal pollutants. Hence this study investigated changes caused by exogenous methyl jasmonate (MeJA; 20 and 100 µM) and salicylic acid (SA; 2 and 20 mM) elicitors in local Karacadağ rice exposed to Pb stress (0, 100, and 400 ppm). The effects of elicitors on photosynthetic pigment content (chlorophyll a, chlorophyll b, and total carotenoid), proline, malondialdehyde (MDA), total phenolic and flavonoid, Pb, and total protein contents in stressed plants were evaluated. All parameters studied increased and decreased at varying rates in the treatment groups compared to the Pb-free group (control), indicating that rice plants were affected by Pb stress. The elicitors (MeJA, SA, and MeJA + SA) were applied by foliar spraying. The elicitor treatments increased photosynthetic pigment content, total protein, proline, total flavonoid, and phenolic contents depending on the elicitor type and concentration. MDA and Pb contents, increasing with Pb toxicity, decreased with elicitor treatments, and the stress degree was reduced. When the elicitors were compared, SA was more effective than MeJA in total flavonoid content at 400 ppm Pb toxicity. However, MeJA was more effective in photosynthetic pigment contents, MDA, total protein, Pb, total phenolic, and proline contents. The best results for all parameters examined in rice plants exposed to Pb toxicity were obtained from the 400 ppm Pb + 2 mM SA + 20 µM MeJA treatment group. In conclusion, this study showed that the combined application of MeJA + SA alleviated the harmful effects of Pb by reducing MDA and increasing photosynthetic pigments, total protein, proline, and secondary metabolites, especially at high Pb concentrations. Consequently, this study demonstrated that the combined use of MeJA and SA in rice plants eliminated the negative effects of stress quite effectively, even at high Pb concentrations. Therefore, future studies should focus on the synergistic application of different elicitors to better understand the effects of heavy metal toxicity on plant growth and development. [ABSTRACT FROM AUTHOR]

HMGR (3-hydroxy-3-methylglutaryl-CoA reductase) plays a crucial role as the first rate-limiting enzyme in the mevalonate (MVA) pathway, which is the upstream pathway of natural rubber biosynthesis. In this study, we carried out whole-genome identification of Taraxacum kok-saghyz (TKS), a novel rubber-producing alternative plant, and obtained six members of the TkHMGR genes. Bioinformatic analyses were performed including gene structure, protein properties, chromosomal localization, evolutionary relationships, and cis-acting element analyses. The results showed that HMGR genes were highly conserved during evolution with a complete HMG-CoA reductase conserved domain and were closely related to Asteraceae plants during the evolutionary process. The α-helix is the most prominent feature of the secondary structure of the TkHMGR proteins. Collinearity analyses demonstrated that a whole-genome duplication (WGD) event and tandem duplication event play a key role in the expansion of this family and TkHMGR1 and TkHMGR6 have more homologous gene between other species. Cis-acting element analysis revealed that the TkHMGR gene family had a higher number of MYB-related, light-responsive, hormone-responsive elements. In addition, we investigated the expression patterns of family members induced by ethylene (ETH) and methyl jasmonate (MeJA), and their expression levels at different stages of T. kok-saghyz root development. Finally, subcellular localization results showed that six TkHMGR members were all located in the endoplasmic reticulum. In conclusion, the results of our study lay a certain theoretical basis for the subsequent improvement of rubber yield, molecular breeding of rubber-producing plants, and genetic improvement of T. kok-saghyz. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION The present study explored the effects of pre‐harvest methyl jasmonates spraying on the volatiles of ‘Cabernet Gernischt’ grapes through the lipoxygenase pathway. Headspace solid‐phase microextraction combined with gas chromatography‐mass spectrometry and an enzyme‐linked immunosorbent assay were utilized to analyze volatile metabolites and key enzyme activities following methyl jasmonates application. Total RNA extraction and cDNA library construction were followed by transcriptome sequencing.The application of 0.1 mmol L−1 methyl jasmonate and 5 mmol L−1 methyl dihydrojasmonate significantly increased the levels of C6 compounds in ‘Cabernet Gernischt’ berries, and also enhanced the utilization of unsaturated fatty acids as precursors in the lipoxygenase‐hydroperoxides lyase pathway. The up‐regulated expression of VvADH1, VvADH2, VvHPL and VvLOX2S genes led to modulations in enzyme activity, thereby enhancing the berries's aromatic profile. There was a significant correlation between linoleic and linolenic acids (i.e. the precursors of the lipoxygenase pathway) and the activities and metabolites of key enzymes.The optimal concentration of methyl jasmonates treatment favorably influences the accumulation of green leaf volatiles in ‘Cabernet Gernischt’ grape. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Elicitors have a substantial impact on the accumulation of phytochemical components in wild plants. The present study aimed to evaluate the impact of salicylic acid (SA) and methyl jasmonate (MJ) on the enrichment of carbazole alkaloids (CAs) in the leaves of Murraya koenigii under controlled environment. Effect of elicitors at 1.0, 1.5 and 2.0 mM and their time of exposition 6 h, 12 h, 24 h, 2 days and 5 days were evaluated. Methanolic extracts of the treated samples were subjected to UPLC-ESI-QTRAP LC-MS/MS analysis for the separation and subsequent quantification of seven identified CAs, viz. murrayamine A, koenigine, koenimbidine, koenimbine, mahanine, 8,8′-biskoenigine and mahanimbine. Accumulation of all the CAs was found to be enhanced with both the elicitors, but it was dependent on the type of elicitor, its concentration, and time of exposition. The data were analyzed through multivariate statistical models, like PCA, HCA and PLS-DA. The analysis revealed that 1.5 mM dose of MJ and SA had a significant influence on CAs accumulation at 24 and 12 h, respectively. Five marker CAs from both MJ and SA-treated samples were identified using VIP scoring. These findings suggest that MJ and SA with their specific concentration and exposition time could be used for the accumulation of particular CA to a substantial limit in this plant. [ABSTRACT FROM AUTHOR]

Abstract The increase in demand for natural rubber has led to the search for alternative sources. Lactuca serriola is emerging as a promising candidate, as the quality of the natural rubber it produces is comparable to that of the Pará Rubber Plant, Hevea brasiliensis. This study examines the effect of methyl jasmonate (MeJA), a known elicitor, on the expression of key rubber biosynthesis pathway genes (HMGR1, HMGS1, CPT2, and SRPP1) in the latex of L. serriola plants. The expression levels of these genes increased significantly after the foliar application of 200 and 400 µM MeJA. The highest relative expression level for HMGR1, HMGS1, CPT2 and SRPP1 was 3.74, 18.56, 11.91and 16.59 fold respectively. Furthermore, the rubber content in L. serriola showed a significant rise post-treatment compared to the control with increasing the level of MeJA (6.19%, 7.24% and 7.85% which correspond to 0, 200 and 400 µM). Gel permeation chromatography revealed an augmentation in the molecular weight of extracted natural rubber from treated plants. Samples treated with 400 µM of MeJA had the highest molecular weight (1570 kg mol−1) compared to control (1186 kg mol−1). This study has demonstrated that MeJA, through the regulation of rubber biosynthesis genes, is capable of enhancing the quality and quantity of natural rubber extracted from alternative sources, such as L. serriola.

Abstract Heavy metal toxicity adversely affects plants by changing physiological, biochemical, and molecular mechanisms. Lead (Pb) is one of the most common heavy metal pollutants. Hence this study investigated changes caused by exogenous methyl jasmonate (MeJA; 20 and 100 µM) and salicylic acid (SA; 2 and 20 mM) elicitors in local Karacadağ rice exposed to Pb stress (0, 100, and 400 ppm). The effects of elicitors on photosynthetic pigment content (chlorophyll a, chlorophyll b, and total carotenoid), proline, malondialdehyde (MDA), total phenolic and flavonoid, Pb, and total protein contents in stressed plants were evaluated. All parameters studied increased and decreased at varying rates in the treatment groups compared to the Pb-free group (control), indicating that rice plants were affected by Pb stress. The elicitors (MeJA, SA, and MeJA + SA) were applied by foliar spraying. The elicitor treatments increased photosynthetic pigment content, total protein, proline, total flavonoid, and phenolic contents depending on the elicitor type and concentration. MDA and Pb contents, increasing with Pb toxicity, decreased with elicitor treatments, and the stress degree was reduced. When the elicitors were compared, SA was more effective than MeJA in total flavonoid content at 400 ppm Pb toxicity. However, MeJA was more effective in photosynthetic pigment contents, MDA, total protein, Pb, total phenolic, and proline contents. The best results for all parameters examined in rice plants exposed to Pb toxicity were obtained from the 400 ppm Pb + 2 mM SA + 20 µM MeJA treatment group. In conclusion, this study showed that the combined application of MeJA + SA alleviated the harmful effects of Pb by reducing MDA and increasing photosynthetic pigments, total protein, proline, and secondary metabolites, especially at high Pb concentrations. Consequently, this study demonstrated that the combined use of MeJA and SA in rice plants eliminated the negative effects of stress quite effectively, even at high Pb concentrations. Therefore, future studies should focus on the synergistic application of different elicitors to better understand the effects of heavy metal toxicity on plant growth and development.

BACKGROUND: Poplar in China has long been plagued by the fall webworm Hyphantria cunea. Enhancing plant immunity using chemical elicitors is an environmentally friendly approach to pest control. The phytohormone methyl jasmonate (MeJA) can stimulate the chemical defenses of poplars against herbivores but has been shown to have limited efficacy in practice. Here, we studied the effects of a MeJA and mesoporous silica nanoparticle (MSN) complex (MeJA@MSN) regarding the induction of poplar resistance to H. cunea, which may provide strategies for the effective use of MeJA. RESULTS: The silicon‐based phytohormone complex (MeJA@MSNs) exhibited excellent biological and physiochemical properties, such as excellent biocompatibility and plant tissue transportability. The changes in metabolites in poplar leaves induced by MeJA, MSNs, and MeJA@MSNs were investigated by metabolic analysis. MeJA@MSNs led to highly potent induced resistance along with elevated salicylaldehyde content, which increased with the dose administered. The salicylaldehyde metabolite showed a strong antifeedant effect on H. cunea larvae at a dosage of 1 μg, with the 50% lethal dose being 20.4 μg/mg. Furthermore, transcriptional analysis showed that MeJA@MSNs upregulated key genes in biosynthetic pathways more than MeJA and MSNs. CONCLUSION: Our results show that MeJA and MSNs interact positively in poplar, leading to salicylaldehyde accumulation and increased induced resistance to H. cunea, providing new insights into the underlying resistance mechanisms induced by MeJA@MSNs. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Abstract Cadmium (Cd) is a biologically non-essential heavy metal, a major soil pollutant, and extremely harmful to plants. The phytohormone methyl jasmonate (MeJA) plays an important role in plant heavy-metal resistance. However, the understanding of the effects of MeJA supply level on alleviating Cd toxicity in plants is limited. Here, we investigated how MeJA regulated the development of physiological processes and cell wall modification in Cosmos bipinnatus. We found that low concentrations of MeJA increased the dry weight of seedlings under 120 µM Cd stress by reducing the transport of Cd from roots to shoots. Moreover, a threshold concentration of exogenous MeJA increased the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in plant roots, the concentration of Cd in the root cell wall, and the contents of pectin and hemicellulose 1 polysaccharides, through converting Cd into pectin-bound forms. These results suggested that MeJA mitigated Cd toxicity by modulating root cell wall polysaccharide and functional group composition, especially through pectin polysaccharides binding to Cd, with effects on Cd transport capacity, specific chemical forms of Cd, and homeostatic antioxidant systems in C. bipinnatus.

Abstract Background One of the most effective strategies to increase phytochemicals production in plant cultures is elicitation. In the present study, we studied the effect of abiotic and biotic elicitors on the growth, key biosynthetic genes expression, antioxidant capacity, and phenolic compounds content in Rhizobium (Agrobacterium) rhizogenes-induced hairy roots cultures of Ficus carica cv. Siah. Methods The elicitors included methyl jasmonate (MeJA) as abiotic elicitor, culture filtrate and cell extract of fungus Piriformospora indica as biotic elicitors were prepared to use. The cultures of F. carica hairy roots were exposed to elicitores at different time points. After elicitation treatments, hairy roots were collected, and evaluated for growth index, total phenolic (TPC) and flavonoids (TFC) content, antioxidant activity (2,2-diphenyl-1-picrylhydrazyl, DPPH and ferric ion reducing antioxidant power, FRAP assays), expression level of key phenolic/flavonoid biosynthesis genes, and high-performance liquid chromatography (HPLC) analysis of some main phenolic compounds in comparison to control. Results Elicitation positively or negatively affected the growth, content of phenolic/flavonoid compounds and DPPH and FRAP antioxidant activities of hairy roots cultures in depending of elicitor concentration and exposure time. The maximum expression level of chalcone synthase (CHS: 55.1), flavonoid 3′-hydroxylase (F3’H: 34.33) genes and transcription factors MYB3 (32.22), Basic helix-loop-helix (bHLH: 45.73) was induced by MeJA elicitation, whereas the maximum expression level of phenylalanine ammonia-lyase (PAL: 26.72) and UDP-glucose flavonoid 3-O-glucosyltransferase (UFGT: 27.57) genes was obtained after P. indica culture filtrate elicitation. The P. indica elicitation also caused greatest increase in the content of gallic acid (5848 µg/g), caffeic acid (508.2 µg/g), rutin (43.5 µg/g), quercetin (341 µg/g), and apigenin (1167 µg/g) phenolic compounds. Conclusions This study support that elicitation of F. carica cv. Siah hairy roots can be considered as an effective biotechnological method for improved phenolic/flavonoid compounds production, and of course this approach requires further research.

Purpose: Lemon (Citrus limon) is a highly important citrus species worldwide. However, its semi-tropical nature makes it susceptible to chilling, extensive research on postharvest treatments to preserve its quality under low temperatures. Research Method: The treatments included 500 μM melatonin (M), 50 μM methyl jasmonate (J), and 5 mM gamma-aminobutyric acid (GABA). Lemons stored at 3 ± 1°C and a relative humidity of 85-95% for 100 days plus 5-day shelf life. Findings: The results revealed that most of the experimental treatments, except for the combination of GABA + J and GABA + J + M, significantly reduced fruit weight loss. Notably, the melatonin treatment showed a 22.7% lower weight loss compared to the control fruits. Furthermore, the melatonin treatment exhibited the highest fruit firmness (49 N), while the control treatment had the lowest (36.3 N). Regarding the quality parameters, individual treatments, and the GABA + M treatment resulted in significantly higher total soluble solids (TSS) and a lower TSS/TA compared to the control at the end of the storage period. Except for the M + GABA and M + J treatments, all other treatments showed higher ascorbic acid content compared to the control. Additionally, the melatonin treatment showed significant differences in various color indices compared to the control. Research limitations: There was no limitation. Originality/Value: Overall, fruits treated with M, J, GABA, and GABA + M demonstrated higher marketability compared to the control and other treatments. Consequently, it is recommended to utilize these treatments individually rather than in combination to maintain the quality of lemon fruits.

Fresh-cut Chinese water chestnuts (CWCs) are susceptible to yellowing and browning during storage due to mechanical damage and the loss of protective outer skin, adversely affecting their marketability and shelf life. Methyl jasmonate (MeJA) is currently extensively used for food preservation, but it has not been used in Chinese water chestnuts. This study investigated the effect of MeJA treatment on the quality of fresh-cut CWCs. Fresh-cut CWCs immersed in 20 μM MeJA solution for 10 min and stored at 10°C for 5 d effectively delayed the yellowing process, reduced the respiration rate, and minimized the weight and soluble solids loss during storage. In addition, MeJA treatment induced the activities of superoxide dismutase (SOD) and catalase (CAT), which improved the antioxidant capacity of fresh-cut CWCs and inhibited the generation of reactive oxygen species (ROS). Meanwhile, MeJA treatment inhibited the activities of phenylalanine aminotransferase (PAL), polyphenol oxidase (PPO) and peroxidase (POD). The results of quantitative real-time PCR (qRT-PCR) showed that MeJA down-regulated the expression of CwCHS1, CwCHS2, CwCHS3 and CwCHI2 in freshly cut CWCs and inhibited the accumulation of flavonoids, thus delaying the surface discoloration of freshly cut CWCs. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a biologically non-essential heavy metal, a major soil pollutant, and extremely harmful to plants. The phytohormone methyl jasmonate (MeJA) plays an important role in plant heavy-metal resistance. However, the understanding of the effects of MeJA supply level on alleviating Cd toxicity in plants is limited. Here, we investigated how MeJA regulated the development of physiological processes and cell wall modification in Cosmos bipinnatus. We found that low concentrations of MeJA increased the dry weight of seedlings under 120 µM Cd stress by reducing the transport of Cd from roots to shoots. Moreover, a threshold concentration of exogenous MeJA increased the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in plant roots, the concentration of Cd in the root cell wall, and the contents of pectin and hemicellulose 1 polysaccharides, through converting Cd into pectin-bound forms. These results suggested that MeJA mitigated Cd toxicity by modulating root cell wall polysaccharide and functional group composition, especially through pectin polysaccharides binding to Cd, with effects on Cd transport capacity, specific chemical forms of Cd, and homeostatic antioxidant systems in C. bipinnatus. [ABSTRACT FROM AUTHOR]

Cardiac glycosides (CGs) are well known for treating congestive heart failure, and several CGs like digoxin, digitoxin, and ouabain are marketed as drugs. In the present study, we have biosynthesized two CGs (CGCL520/227 and CGCL534/209) and elicited them up to 537- and 357-fold respectively in response to methyl jasmonate (MJ) treatment. For identification of the key enzyme involved in its biosynthesis, a comparative transcriptome sequencing of control and MJ elicited (75.0 mg L−1 for 3 d) callus culture was done. A total of 17,898 transcripts were expressed across all samples. Annotated unigenes were functionally categorized based on gene ontology. A total of 7625 unigenes were significantly matched in the KEGG database involved in 151 different plant metabolism pathways. Upon digital expression analysis, 2924 MJ-responsive transcripts were identified, and among them 166 were unique for MJ-treated samples. A majority of upregulated transcripts were categorized under hydrolase activity, oxido-reductase activity, metabolic processes, and carbohydrate metabolic process. Based on their role in terpenoid, steroid, and cardenolide pathways, 295 putative unigenes representing 24 gene families involved in CG biosynthesis were identified. Expression analysis revealed that 12 transcripts involved in steroid and cardenolide biosynthetic pathways were upregulated in response to MJ. The highest expression was recorded for squalene monooxygenase (SMO) with 43-fold upregulation, followed by sterol delta7 reductase (DWF5) with 22.2-fold. C-5 sterol desaturase (STE1), 4-diphosphocytidyl-2-C-methyl-D-erythritolkinase/4diphosphocytidyl-2C-methyl-D-erythritol synthase (CMK), 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HDR), acetyl-CoA C-acetyltransferase (AACT), mono-oxygenases (MO), and progesterone 5β-reductase (PBR) showed high and significant expressions of 16.4-, 16.1-, 14.8-, 14.7-, 13.4-, and 11.3-fold, respectively. This study not only identifies MJ-responsive CGs and related transcripts involved in CG biosynthesis, but also provides scope for the development of biotechnological process for biosynthesis and enrichment of targeted CGs using identified rate-limiting key enzymes. [ABSTRACT FROM AUTHOR]

In the Brassicaceae family, a glucosinolate-myrosinase-based system exists against herbivory Glucosinolate-Myrosinase system is differentially compartmentalized but substrate glucosinolate enter in contact with the enzyme myrosinase when plant tissues are attacked by insects. The glucosinolate breakdown into a variety of biologically active toxins further deterrenting the herbivory of different chewing and sucking insect pests. The myrosinase enzyme present is in myrosin cells were genetically removed from B. napus plant during the seed development. These genetically modified myrosin cells free plants are known as MINELESS plant. Genetically modified oilseed rape (Brassica napus) was produced by removing toxic mines. Here, we evaluauted the tritrophic interaction between Brassica napus wildtype and genetically modified and polyphagous pest Spodoptera. In force feeding experiment, larval growth of S. exigua was slow and gained less weight on MINELESS seedlings as compared to wild-type seedling. Additionally, highest amount of total glucosinolate was found in MINELESS control than that of wild type control. Myrosinase activity was not affected by the S. exigua feeding on the MINELESS plants. However, reduced activity of myrosinase was observed in the wild-type seedlings. Moreover, the S. exigua induced the concentration of tryptophan derived glucosinolate (indol-3-yl-methyl, 1-methoxy-indol-3-yl-methyl) that was found slightly higher in MINELESS seedlings than on wild-type seedling. Feeding of S. exigua deregulated the level of glucosinolate hydrolysis products in both types of plants. Transcriptional data after S. exigua feeding on wildtype and MINELESS showed differential response of methyl jasmonate and glucosinolate responsive genes were observed. We also observed that after methyl jasmonate treatment, methyl jasmonate and glucosinolate responsive genes were incease in the wild-type and MINELESS seedlings showing their negative effect on the growth of S. exigua. Overall, generalist insect results are interesting by considering the function of myrosin cells and binary defense system. Further, same experiment should be performed against generalist and specialist insect herbivores of above- and below-ground. [ABSTRACT FROM AUTHOR]

Heat stress is a major environmental stress that affects the growth and development of plants. Korean fir (Abies koreana), a rare species endemic to South Korea, is sensitive to global climate change. The effect of exogenous methyl jasmonate (MeJA) on heat stress tolerance was, therefore, investigated in this species. During heat stress, the expression levels of eight genes (AkNAC19, AkMPK6, AkERF4, AkEFP, AkNAC2, AkbHLH, AkHSP17.6, and AkMYB123) were assessed in needles of A. koreana following treatment with 0, 0.1, 1.0, or 2.0 mM MeJA. Optimal upregulation of expression of most genes was observed 24 h post-treatment with 2.0 mM MeJA. Similar results were obtained when gene expression was analyzed 1, 2, 4, and 8 days post-treatment with 2.0 mM MeJA. Under heat stress conditions, plants treated with 2.0 mM MeJA initially showed a rapid decline in electrolyte leakage and higher chlorophyll content after 28 days of heat stress; however, opposite trends were observed in untreated plants, indicating that MeJA mediated tolerance to heat stress. Higher levels of expression of AkERF4, AkNAC2, and AkHSP17.6 were observed in MeJA-treated needles than in untreated needles, indicating these genes were strongly associated with MeJA-mediated heat tolerance. Therefore, these results suggest that the ability of Korean fir to tolerate abiotic stress is associated with endogenous MeJA synthesis or signaling, and identifies AkERF4, AkNAC2, and AkHSP17.6 as potential candidates for genes involved in the stress-tolerance mechanism. [ABSTRACT FROM AUTHOR]

This study investigates the impact of methyl jasmonate (MeJA) on the volatile oil composition of Schizonepeta tenuifolia and elucidates the function of the StTPS45 gene, a key player in terpenoid biosynthesis. The effect of different concentrations of MeJA (0, 50, 100, 200, and 300 μmol/L) on the growth of S. tenuifolia adventitious bud clusters was analyzed over a 20 d period. Using gas chromatography–mass spectrometry (GC-MS), 17 compounds were identified from the adventitious bud clusters of S. tenuifolia. Significant changes in the levels of major monoterpenes, including increased contents of (+)-limonene and (+)-menthone, were observed, particularly at higher concentrations of MeJA. Analysis of transcriptome data from three groups treated with 0, 100, and 300 μmol/L MeJA revealed significant changes in the gene expression profiles following MeJA treatment. At 100 μmol/L MeJA, most terpene synthase (TPS) genes were overexpressed. Additionally, gene expression and functional predictions suggested that StTPS45 acts as germacrene D synthase. Therefore, StTPS45 was cloned and expressed in Escherichia coli, and enzyme activity assays confirmed its function as a germacrene D synthase. Molecular docking and structural prediction of StTPS45 further suggested specific interactions with farnesyl diphosphate (FPP), aligning with its role in the terpenoid synthesis pathway. These findings provide valuable insights into the modulation of secondary metabolite pathways by jasmonate signaling and underscore the potential of genetic engineering approaches to enhance the production of specific terpenoids in medicinal plants. [ABSTRACT FROM AUTHOR]

2,4-Dinitrophenol (2,4-DNP) is recognized as an emerging contaminant due to its high toxicity and poor biodegradability, posing a threat to animals, plants, and human health. The efficient removal of 2,4-DNP remains a challenging issue in phytoremediation research, particularly because of its toxic effects on plants. To address this, a hydroponic simulation experiment was conducted to investigate the impact of adding exogenous methyl jasmonate (MeJA) on the tolerance and purification capabilities of Salix matsudana Koidz (S. matsudana) seedlings exposed to 2,4-DNP. The results indicated that the addition of exogenous MeJA mitigated the damage caused by 2,4-DNP to S. matsudana seedlings by enhancing the activity of antioxidant enzymes, reducing excess reactive oxygen species (ROS), lowering membrane lipid peroxidation, and minimizing membrane damage. Notably, the most effective alleviation was observed with the addition of 50 mg·L–1 MeJA. Furthermore, exogenous MeJA helped maintain the biomass indices of S. matsudana seedlings under 2,4-DNP stress and increased the removal efficiency of 2,4-DNP by these seedlings. Specifically, the addition of 50 mg·L–1 MeJA resulted in a removal percentage of 79.57%, which was 11.88% higher than that achieved with 2,4-DNP treatment. In conclusion, exogenous MeJA can improve the plant resistance and enhance 2,4-DNP phytoremediation. [ABSTRACT FROM AUTHOR]

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To investigate the effects of exogenous methyl jasmonate (MeJA) on the post-harvest quality of fresh lotus seed, MeJA (100 µmol/L) was used to soak the fresh lotus seed with water as the control. The changes in the color difference (L*, a*, b*), nutrient content (starch, soluble sugar), and other physiological and biochemical indexes (weight loss rate, total phenol content, malondialdehyde content, hydrogen peroxide content, polyphenol oxidase activity, superoxide dismutase activity, catalase activity and peroxidase activity) were compared every 2 days. The results showed that compared with the control group, the MeJA treatment effectively maintained the postharvest color of fresh lotus seed. After 8 days of storage, compared with the control group, the MeJA-treated group had a lower weight loss rate (decreased by 33.84%), and higher starch content (increased by 38.34 mg/g), higher soluble sugar content (increased by 70.58 mg/g), along with a reduced total phenol content, suppressed PPO activity, MDA content and H2O2 accumulation, and enhanced SOD, CAT and POD activities. The above results revealed that the MeJA treatment could delay the post-harvest quality decline of fresh lotus seed through reducing material consumption, maintaining starch and soluble sugar contents, reducing the oxidation of phenols, improving the activities of antioxidant enzymes, as well as maintaining the cell membrane integrity, thereby prolonging their shelf life. [ABSTRACT FROM AUTHOR]

Background: One of the most effective strategies to increase phytochemicals production in plant cultures is elicitation. In the present study, we studied the effect of abiotic and biotic elicitors on the growth, key biosynthetic genes expression, antioxidant capacity, and phenolic compounds content in Rhizobium (Agrobacterium) rhizogenes-induced hairy roots cultures of Ficus carica cv. Siah. Methods: The elicitors included methyl jasmonate (MeJA) as abiotic elicitor, culture filtrate and cell extract of fungus Piriformospora indica as biotic elicitors were prepared to use. The cultures of F. carica hairy roots were exposed to elicitores at different time points. After elicitation treatments, hairy roots were collected, and evaluated for growth index, total phenolic (TPC) and flavonoids (TFC) content, antioxidant activity (2,2-diphenyl-1-picrylhydrazyl, DPPH and ferric ion reducing antioxidant power, FRAP assays), expression level of key phenolic/flavonoid biosynthesis genes, and high-performance liquid chromatography (HPLC) analysis of some main phenolic compounds in comparison to control. Results: Elicitation positively or negatively affected the growth, content of phenolic/flavonoid compounds and DPPH and FRAP antioxidant activities of hairy roots cultures in depending of elicitor concentration and exposure time. The maximum expression level of chalcone synthase (CHS: 55.1), flavonoid 3′-hydroxylase (F3'H: 34.33) genes and transcription factors MYB3 (32.22), Basic helix-loop-helix (bHLH: 45.73) was induced by MeJA elicitation, whereas the maximum expression level of phenylalanine ammonia-lyase (PAL: 26.72) and UDP-glucose flavonoid 3-O-glucosyltransferase (UFGT: 27.57) genes was obtained after P. indica culture filtrate elicitation. The P. indica elicitation also caused greatest increase in the content of gallic acid (5848 µg/g), caffeic acid (508.2 µg/g), rutin (43.5 µg/g), quercetin (341 µg/g), and apigenin (1167 µg/g) phenolic compounds. Conclusions: This study support that elicitation of F. carica cv. Siah hairy roots can be considered as an effective biotechnological method for improved phenolic/flavonoid compounds production, and of course this approach requires further research. [ABSTRACT FROM AUTHOR]

(1) Background: Phytochemicals are crucial antioxidants that play a significant role in preventing cancer. (2) Methods: We explored the use of methyl jasmonate (MeJA) in the in vitro cultivation of D. morbifera adventitious roots (DMAR) and evaluated its impact on secondary metabolite production in DMAR, optimizing concentration and exposure time for cost-effectiveness. We also assessed its anti-inflammatory and anti-lung cancer activities and related gene expression levels. (3) Results: MeJA treatment significantly increased the production of the phenolic compound 3,5-Di-caffeoylquinic acid (3,5-DCQA). The maximum 3,5-DCQA production was achieved with a MeJA treatment at 40 µM for 36 h. MeJA-DMARE displayed exceptional anti-inflammatory activity by inhibiting the production of nitric oxide (NO) and reactive oxygen species (ROS) in LPS-induced RAW 264.7 cells. Moreover, it downregulated the mRNA expression of key inflammation-related cytokines. Additionally, MeJA-DMARE exhibited anti-lung cancer activity by promoting ROS production in A549 lung cancer cells and inhibiting its migration. It also modulated apoptosis in lung cancer cells via the Bcl-2 and p38 MAPK pathways. (4) Conclusions: MeJA-treated DMARE with increased 3,5-DCQA production holds significant promise as a sustainable and novel material for pharmaceutical applications thanks to its potent antioxidant, anti-inflammatory, and anti-lung cancer properties. [ABSTRACT FROM AUTHOR]

Oregano (Origanum L.) is a medicinal plant from the Lamiaceae family that its role in the treatment of various diseases is known since ancient time. This research was conducted with the aim of evaluating the effects of elicitation with methyl jasmonate (MeJA) on some physiological and biochemical properties of the oregano (Origanum vulgare L.) medicinal plant. An experiment in the form of a two-factor factorial completely randomized design were performed. The elicitor concentration at 4 levels (zero, 0.1, 0.5 and 2.5 mM) and the exposure time after applying the MeJA treatment at 4 levels (zero, 24, 48 and 96 h) were considered as the main factors. The highest contents of Chlorophyll a (Chl a) were seen in two treatment combinations of 0.0 mM MeJA, 48 h and 0.5 mM MeJA, 24 h. While, the highest level of Peroxidase (POX) activity was obtained in two treatments of 2.5 mM and 0.5 mM MeJA. The 2.5 mM concentration resulted in higher concentration of antioxidant enzymes up to 96 h after the treatment. Generally, the foliar spraying of MeJA caused an increased amount of Chl a, proline, antioxidant enzymes including ascorbate peroxidase (APX), catalase (CAT), polyphenol oxidase (PPO) and peroxidase (POX). But the MeJA concentration and post-treatment time showed no significant effect on the content of total soluble protein (TSP), chlorophyll b (Chl b) and carotenoids (CAR). The results of this research can be useful in botanical, biological, agricultural biotechnology and medicinal studies on Origanum and other medicinal plants. [ABSTRACT FROM AUTHOR]

To what extent particular plant defences against herbivorous insects are constitutive or inducible will depend on the costs and benefits in their neighbourhood. Some defensive chemicals in leaves are thought to be costly and hard to produce rapidly, while others, including volatile organic compounds that attract natural enemies, might be cheaper and can be released rapidly. When surrounding tree species are more closely related, trees can face an increased abundance of both specialist herbivores and their parasitoids, potentially increasing the benefits of constitutive and inducible defences. To test if oaks (Quercus robur) respond more to herbivore attacks with volatile emission than with changes in leaf phenolic chemistry and carbon to nitrogen ratio (C: N), and whether oaks respond to the neighbouring tree species, we performed an experiment in a forest in Poland. Oak saplings were placed in neighbourhoods dominated by oak, beech, or pine trees, and half of them were treated with the phytohormone methyl jasmonate (elicitor of anti-herbivore responses). Oaks responded to the treatment by emitting a different volatile blend within 24 h, while leaf phenolic chemistry and C: N remained largely unaffected after 16 days and multiple treatments. Leaf phenolics were subtly affected by the neighbouring trees with elevated flavan-3-ols concentrations in pine-dominated plots. Our results suggest that these oaks rely on phenols as a constitutive defence and when attacked emit volatiles to attract natural enemies. Further studies might determine if the small effect of the neighbourhood on leaf phenolics is a response to different levels of shading, or if oaks use volatile cues to assess the composition of their neighbourhood. [ABSTRACT FROM AUTHOR]

Methyl jasmonate (MeJA) is a plant hormone in higher plants and plays an important role in physiological response and stress resistance of plants under various biotic and abiotic stresses. In this study, the effects of exogenous MeJA on the growth of rice seedlings under cadmium (Cd) stress were studied via hydroponics experiment. The results showed that MeJA could effectively relieve plant growth inhibition caused by Cd stress, and reduce Cd content in root and shoot parts of rice by 14. 42% and 11. 63%,respectively. Non-invasive micro-test analysis indicated that MeJA effectively reduced net Cd2+influx. Moreover, MeJA changed the cell wall structure and increased root and shoot cell wall thickness by 27. 02% and 39. 96%,respectively. The Cd content in pectin, cellulose and hemicellulose increased, thus Cd was effectively prevented from entering cytoplasm and organelles, and the biotoxicity of Cd to plant cells was reduced. Gene expression analysis showed that the decrease of Cd absorption and transportation in rice plants was directly related to the decreased expression of OsNramp1、OsNramp5 and OsHMA2 genes. Overall, this study provides a feasible way for decreasing Cd content in rice plants. [ABSTRACT FROM AUTHOR]

SUMMARY: Anthocyanin generation in apples (Malus domestica) and the pigmentation that results from it may be caused by irradiation and through administration of methyl jasmonate (MeJA). However, their regulatory interrelationships associated with fruit coloration are not well defined. To determine whether MdERF109, a transcription factor (TF) involved in light‐mediated coloration and anthocyanin biosynthesis, has synergistic effects with other proteins, we performed a yeast two‐hybrid assessment and identified another TF, MdWER. MdWER was induced by MeJA treatment, and although overexpression of MdWER alone did not promote anthocyanin accumulation co‐overexpression with MdERF109 resulted in significantly increase in anthocyanin biosynthesis. MdWER may form a protein complex with MdERF109 to promote anthocyanin accumulation by enhancing combinations between the proteins and their corresponding genes. In addition, MdWER, as a MeJA responsive protein, interacts with the anthocyanin repressor MdJAZ2. Transient co‐expression in apple fruit and protein interaction assays allowed us to conclude that MdERF109 and MdJAZ2 interact with MdWER and take part in the production of anthocyanins upon MeJA treatment and irradiation. Our findings validate a role for the MdERF109‐MdWER‐MdJAZ2 module in anthocyanin biosynthesis and uncover a novel mechanism for how light and MeJA signals are coordinated anthocyanin biosynthesis in apple fruit. Significance Statement: Our findings validate a role for the MdERF109‐MdWER‐MdJAZ2 module in anthocyanin biosynthesis and uncover a novel mechanism for how light and MeJA signals are coordinated anthocyanin biosynthesis in apple fruit. [ABSTRACT FROM AUTHOR]

This work studies the impact of foliar application of methyl jasmonate (MeJA) and methyl jasmonate plus urea (MeJA + Ur) on the evolution of amino acid content in 'Tempranillo' grapes during ripening, across two vintages. To achieve this goal, sample grapes were harvested at five different timing. Fol1: 1 day before first foliar application; Fol2: 1 day before second foliar application; Preharvest: 15 days after second foliar application; Harvest: the day of harvest; and Postharvest: 15 days after harvest. The effect of foliar treatments was season dependent, being effective to improve the amino acids content of grapes only in the first vintage. Among the treatments studied, foliar application of MeJA-Ur showed better results. The evolution of amino acids during ripening also was different among seasons. Overall, in the 2019, amino acids reached their highest content at Preharvest or Harvest samples, whereas in the 2020 season, these highest concentrations were reached at Postharvest. Asparagine might serve as a suitable amino acid for controlling grape ripening, as its content decreased from Fol1 to Postharvest in the two vintages. Moreover, differences on the total amino acids content at Harvest date between vintages were observed, probably due to different climatological conditions. Therefore, this study pioneers the examination of the impact of foliar applications of MeJA and MeJA + Ur on the amino acids evolution in 'Tempranillo' grapes during ripening. The need for further research is clear to comprehend the complex interaction between foliar treatments and grape amino acids dynamics for optimizing nitrogen quality of grapes. [ABSTRACT FROM AUTHOR]

Main conclusion: Overexpression of Artemisia annua jasmonic acid carboxyl methyltransferase (AaJMT) leads to enhanced artemisinin content in Artemisia annua. Artemisinin-based combination therapies remain the sole deterrent against deadly disease malaria and Artemisia annua remains the only natural producer of artemisinin. In this study, the 1101 bp gene S-adenosyl-l-methionine (SAM): Artemisia annua jasmonic acid carboxyl methyltransferase (AaJMT), was characterised from A. annua, which converts jasmonic acid (JA) to methyl jasmonate (MeJA). From phylogenetic analysis, we confirmed that AaJMT shares a common ancestor with Arabidopsis thaliana, Eutrema japonica and has a close homology with JMT of Camellia sinensis. Further, the Clustal Omega depicted that the conserved motif I, motif III and motif SSSS (serine) required to bind SAM and JA, respectively, are present in AaJMT. The relative expression of AaJMT was induced by wounding, MeJA and salicylic acid (SA) treatments. Additionally, we found that the recombinant AaJMT protein catalyses the synthesis of MeJA from JA with a Km value of 37.16 µM. Moreover, site-directed mutagenesis of serine-151 in motif SSSS to tyrosine, asparagine-10 to threonine and glutamine-25 to histidine abolished the enzyme activity of AaJMT, thus indicating their determining role in JA substrate binding. The GC–MS analysis validated that mutant proteins of AaJMT were unable to convert JA into MeJA. Finally, the artemisinin biosynthetic and trichome developmental genes were upregulated in AaJMT overexpression transgenic lines, which in turn increased the artemisinin content. [ABSTRACT FROM AUTHOR]

This study aimed to reveal the impact of MeJA and ZnSO4 treatments on the physiological metabolism of barley seedlings and the content of phenolic acid. The results showed that MeJA (100 μM) and ZnSO4 (4 mM) treatments effectively increased the phenolic acid content by increasing the activities of phenylalanine ammonia-lyase and cinnamate-4-hydroxylase (PAL) and cinnamic acid 4-hydroxylase (C4H) and by up-regulating the expression of genes involved in phenolic acid synthesis. As a result of the MeJA or ZnSO4 treatment, the phenolic acid content increased by 35.3% and 30.9% at four days and by 33.8% and 34.5% at six days, respectively, compared to the control. Furthermore, MeJA and ZnSO4 treatments significantly increased the malondialdehyde content, causing cell membrane damage and decreasing the fresh weight and seedling length. Barley seedlings responded to MeJA- and ZnSO4-induced stress by increasing the activities of antioxidant enzymes and controlling their gene expression levels. Meanwhile, MeJA and ZnSO4 treatments significantly upregulated calcium-adenosine triphosphate, calmodulin-dependent protein kinase-related kinase, and calmodulin-dependent protein genes in barley seedlings. This suggested that Ca2+ may be the signaling molecule that promotes phenolic acid synthesis under MeJA and ZnSO4 treatment. This study deepens the understanding of the phenolic acid enrichment process in barley seedlings under MeJA and ZnSO4 treatments. [ABSTRACT FROM AUTHOR]

Purpose: Lemon (Citrus limon) is a highly important citrus species worldwide. However, its semi-tropical nature makes it susceptible to chilling, extensive research on postharvest treatments to preserve its quality under low temperatures. Research Method: The treatments included 500 µM melatonin (M), 50 µM methyl jasmonate (J), and 5 mM gamma-aminobutyric acid (GABA). Lemons stored at 3 ± 1°C and a relative humidity of 85-95% for 100 days plus 5-day shelf life. Findings: The results revealed that most of the experimental treatments, except for the combination of GABA + J and GABA + J + M, significantly reduced fruit weight loss. Notably, the melatonin treatment showed a 22.7% lower weight loss compared to the control fruits. Furthermore, the melatonin treatment exhibited the highest fruit firmness (49 N), while the control treatment had the lowest (36.3 N). Regarding the quality parameters, individual treatments, and the GABA + M treatment resulted in significantly higher total soluble solids (TSS) and a lower TSS/TA compared to the control at the end of the storage period. Except for the M + GABA and M + J treatments, all other treatments showed higher ascorbic acid content compared to the control. Additionally, the melatonin treatment showed significant differences in various color indices compared to the control. Research limitations: There was no limitation. Originality/Value: Overall, fruits treated with M, J, GABA, and GABA + M demonstrated higher marketability compared to the control and other treatments. Consequently, it is recommended to utilize these treatments individually rather than in combination to maintain the quality of lemon fruits. [ABSTRACT FROM AUTHOR]

The demand for economically valuable terpenoid-derived compounds, especially those extracted from patchouli plants, is experiencing exponential growth. These compounds are potentially applied in a wide range of industrial sectors including food manufacturing, perfumeries, and pharmaceuticals. Nevertheless, there is a need for further development in patchouli plant cultivation to align with market demands. Therefore, employing robust in vitro-based propagation methods could offer significant advantages. Furthermore, this technique is also used for plant metabolites enhancement. This strategy applies the methyl jasmonate (MeJA) elicitor to boost the production of secondary metabolites. In Indonesia, patchouli var. Sidikalang is extensively cultivated in many areas. This study aims to evaluate the effect of naphtaleneacetic acid (NAA) and 6-benzylamino purine (BAP) to increase plant growth via in vitro culture. Furthermore, we also investigate the effect of MeJA on the metabolite profiles and on the AACT gene expression. Our findings revealed that the combination of 2.5 µM of BAP and 0.25 µM of NAA resulted in optimal growth and high rate of organogenesis across all growth parameters. Our data also successfully identified 50 dominant compounds, each with varying percentage areas. Notably, patchouli alcohol emerged as the primary compound in the tricyclic sesquiterpene group, consistently present in all treatment groups. Furthermore, the expression of the PatAACT gene significantly increased by 7.42-fold after treatment with MeJA at 100 µM and by 2,9-fold after treatment with MeJA at 300 µM, compared to the control. Altogether, our findings might offer new insight in P. cablin propagation and new strategy for patchouli-derived metabolites using exogenous MeJA.

Abstract [Objective] The study aims to investigate the differential efficacy of anti-leaf spot in barley (Hordeum vulgare L.) of various concentrations of exogenous methyl jasmonate (MeJA) and understand the underlying mechanisms, thereby providing a foundation for the application of MeJA in controlling barley leaf spot. [Methods] We used ‘Mengpimai 3’ (MP3) seedlings as materials and conducted three different treatments: Inoculating the barley leaves with sterile water without any Bipolaris sorokiniana (the causal agent of the disease), inoculating the barley leaves with sterile water after treatment, and treating the barley leaves with different concentrations (0.5, 1.0, 1.5, 2.0, 2.5 mmol/L) of methyl jasmonate (MeJA) before inoculation with the pathogen. The disease incidence was investigated at the three-leaf stage based on disease index to determine the optimal MeJA concentration. We measured antioxidant enzyme activities, anti-disease-related enzyme activities, malondialdehyde, proline, soluble sugar, and soluble protein contents, and the expression levels of related genes under no inoculating treatment, inoculation treatment, and inoculating + optimal MeJA concentration treatment. [Results] (1) Exogenous application of MeJA enhanced MP3 resistance against spot blotch, particularly at 1.5 mmol/L where there was a significant reduction of 19.03% (P

Volatiles are an important aspect of the flavor quality of tomato fruits. However, whether volatiles in tomato fruits respond to the regulation of exogenous methyl jasmonate (MeJA) remains unclear. In this study, four concentrations of MeJA (1, 10, 100 and 200 μmol/L) were sprayed on ‘Chaoyan 298’ tomatoes before harvest, and an equal volume of ultrapure water was used as the control. Ripe fruits were harvested and analyzed for the composition and content of volatile compounds by headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Meanwhile, the optimal concentration of MeJA for improving the flavor quality of tomatoes was determined by multivariate statistical analysis. The results showed that a total of 71 volatile components were detected in the 5 groups, including 23 aldehydes, 17 alcohols, 8 ketones, 7 esters, 6 hydrocarbons and 10 other substances. Compared with the control group, exogenous application of MeJA increased the number and total amount of volatile compounds in tomato fruits, which increased first and then decreased with the increase in MeJA concentration, reaching the maximum value at 100 μmol/L MeJA concentration. Altogether 33 components were common to all groups, with the most abundant one being (Z)-3-hexen-1-ol. A total of 13 characteristic aroma components were identified in all tomato fruits, which mainly contributed to green, fruity and flowery notes. Overall, our results provide theoretical support that exogenous MeJA can improve that flavor quality of tomato fruits, which are conducive to further exploring the regulation mechanism of volatile compound biosynthesis in tomato fruits.