Application Of Jasmonic Acid Research Articles

Application of exogenous jasmonic acid enhances the resistance of pak choi (Brassica chinensis L.) to high levels of selenium-toxicity in the soil

Application of exogenous jasmonic acid enhances the resistance of pak choi (Brassica chinensis L.) to high levels of selenium-toxicity in the soil

Exogenously Applied Gibberellic Acid Alters Cannabinoid Profile in Cannabis sativa L.

Cannabis sativa (C. sativa L.) has garnered significant attention worldwide due to its widespread use as a pharmaceutical agent. With the increasing clinical application of C. sativa and cannabinoid therapeutics, there is strong interest in the development of superior plant varieties and optimisation of growth conditions to enhance secondary metabolite yield. Our RNA sequencing analysis revealed differential expression of hormone-related transcripts in developing C. sativa trichomes, suggesting the involvement of hormone signalling pathways in cannabinoid production. Leveraging the potency of exogenous hormones on plants, this study sought to determine if the application of cytokinin (CK), gibberellic acid (GA) and jasmonic acid (JA) modified trichome morphology and the cannabinoid profile over an 8-week period following the induction of flowering. Exogenous hormone application led to alterations in trichome morphology, with each treatment significantly reducing trichome head width by the final week of assessment. Interestingly, GA application also resulted in a significant reduction in the concentration of Δ-9-tetrahydrocannabinol (THC), Δ-9-tetrahydrocannabinolic acid (THCA), cannabidiol (CBD) and cannabidiolic acid (CBDA) by week 8 post floral induction, however, JA and CK treatment did not consistently modulate the accumulation of these cannabinoids. The minor cannabinoids, cannabidivaranic acid (CBDVA), cannabicyclolic acid (CBLA), cannabicyclol (CBL), cannabichromene (CBC), cannabigerolic acid (CBGA) and cannabigerol (CBG), were also affected by hormone treatments, with varying degrees of accumulation observed. These findings underscore the intricate interplay between phytohormones and secondary metabolite biosynthesis in C. sativa. Our study highlights the potential of hormone modulation as a strategy to enhance cannabinoid yield and offers some insights into the regulatory mechanisms governing cannabinoid biosynthesis in C. sativa trichomes.

Combined Effects of Heavy Metal and Simulated Herbivory on Leaf Trichome Density in Sunflowers

Trichomes play a key role in both heavy metal tolerance and herbivory defense, and both stressors have been shown to induce increased trichome density. However, the combined effect of these stressors on trichome density in general, and specifically on metal-hyperaccumulating plants, has yet to be examined. The aim of this study was to test the effect of cadmium availability and herbivory on leaf trichome density and herbivore deterrence in the metal hyperaccumulator Helianthus annuus. To test this, H. Annuus plants were grown in control pots or pots inoculated with 10 mg/kg cadmium and were subjected to either no herbivory or simulated herbivory using mechanical damage and foliar jasmonic acid application. Herbivore deterrence was tested in a feeding assay using Spodoptera littoralis caterpillars. Interestingly, while the trichome density of H. annuus increased by 79% or 53.5% under high cadmium availability or simulated herbivory, respectively, it decreased by 26% when the stressors were combined. Furthermore, regardless of cadmium availability, simulated herbivory induced a 40% increase in deterrence of S. littoralis. These findings suggest that the combination of metal availability and herbivory might present excessive stress to hyperaccumulators. Moreover, they suggest that the risk of metal bioaccumulation in phytoremediation can be reduced by simulated herbivory.

Integrated Biomarker Response Version 2 (IBRv2)-Assisted Examination to Scrutinize Foliar Application of Jasmonic Acid (JA) and Zinc Oxide Nanoparticles (ZnO NPs) Toward Mitigating Drought Stress in Sugar Beet

Integrated Biomarker Response Version 2 (IBRv2)-Assisted Examination to Scrutinize Foliar Application of Jasmonic Acid (JA) and Zinc Oxide Nanoparticles (ZnO NPs) Toward Mitigating Drought Stress in Sugar Beet

Sweet Immunity in Action: Unlocking Stem Reserves to Improve Yield and Quality. A Potential Key Role for Jasmonic Acid.

Common agronomic practices such as stem topping, side branch removal, and girdling can induce wound priming, mediated by jasmonic acid (JA). Low light conditions during greenhouse tomato production make the leaves more sensitive to the application of exogenous sugar, which is perceived as a "danger" in accordance with the concept of "Sweet Immunity". Consequently, source-sink balances are altered, leading to the remobilization of stem starch reserves and enabling the redirection of more carbon toward developing fruits, thereby increasing tomato yield and fruit quality. Similarities are drawn with the mobilization of fructans following defoliation of fodder grasses (wounding) and the remobilization of fructan and starch reserves under terminal drought and heat stress in wheat and rice (microwounding, cellular leakage). A central role for JA signaling is evident in all of these processes, closely intertwining with sugar signaling pathways. Therefore, JA signaling, associated with wounding and sugar priming events, offers numerous opportunities to alter source-sink balances across a broader spectrum of agricultural and horticultural crops, for instance, through the exogenous application of JA and fructans or a combination. This may entail reconfiguring and reversing phloem connections, potentially leading to an enhanced yield and product quality. Such processes may also disengage the growth-defense trade-off in plants.

Integrative metabolome and transcriptome analysis reveals GbKCS and GbMYB involved in the biosynthesis of ginkgolic acids

Ginkgolic acids is a sort of phenolic lipid compound predominantly enriched in the episperm of Ginkgo biloba. Ginkgolic acids exhibits cytotoxicity and allergenic effects, providing a defense against a variety of biotic stresses from insects, fungus, and bacteria. Ginkgolic acids specifically accumulates in the episperm of Ginkgo biloba, providing the seeds with a unique defence mechanism against biotic stresses and ensuring their survival. However, the regulatory mechanism of ginkgolic acids (GA) biosynthesis remains unclear. In this study, we performed combined metabolome and transcriptome analysis to identify key genes and metabolites involved in ginkgolic acids biosynthesis. The ginkgolic acids, including 6-[(8Z)-Pentadecenyl]-salicylic acid (GA 15:1), 2-hydroxy-6-pentadecylsalicylic acid (GA 15:0) and 5-(8-Pentadecenyl)-1, 3-benzenediol (BL 15:1), as well as their precursors, palmitic acid (FA 16:0) and palmitoleic acid (FA 16:1) were detected and showed regular changes in content during episperm development. From co-expression profiles of the differentially expressed genes, three enzyme-encoding genes including one ketoacyl-CoA synthase gene (GbKCS5) and two long-chain acyl-CoA synthase genes (GbAcsl4 and GbAcsl7) positively associated to GA 15:1 were identified as key candidates. Furthermore, co-expression analysis demonstrates that these genes might be negatively and positively regulated by the bHLH and MYB transcription factors, respectively. In addition, the endogenous jasmonic acid (JA) level in Ginkgo episperm were strongly associated with candidate ginkgolic-acid-related genes and metabolites. And JA may be an important regulator involved in ginkgolic acids biosynthesis. Exogenous JA treatment improved the expression of the GbMYB14, GbKCS5, GbAcsl4 and GbAcsl7 genes, while inhibited most Gb-bHLH genes, which was proposed to be significantly increased ginkgolic acids content. Our findings indicate that application of JA in the Ginkgo episperm can alter the expression levels of genes associated with ginkgolic acids and increase the production of ginkgolic acids. This provides a new insight for research on the regulation and utilization of ginkgolic acids.

Jasmonic Acid and Salicylic Acid improved resistance against Spodoptera frugiperda Infestation in maize by modulating growth and regulating redox homeostasis

Exploring host plant resistance and elevating plant defense mechanisms through the application of exogenous elicitors stands as a promising strategy for integrated pest management. The fall armyworm, a pernicious menace to grain crops in tropical and subtropical regions, stands as a formidable threat due to its capacity for devastation and a wide-ranging spectrum of host plants. There is no literature regarding artificially induced resistance in maize against fall armyworm (Spodoptera frugiperda) by exogenous application of phytohormones. The present investigation was performed to evaluate the role of jasmonic acid (JA) and salicylic acid (SA) on two maize hybrids namely FH-1046 and YH-1898 against fall armyworm. Results showed that plant height, biomass and lengths, fresh and dry weight of root shoot which decreased with armyworm infestation improved with phytohormonal application. JA treatment resulted in a higher increase in all attributes as compared to SA treatment. Improvement in relative water contents, photosynthetic pigments and pronounced levels of phenol and proline accumulation were observed in infested plants after JA treatment. Infested plants recovered from oxidative stress as JA application activated and increased the antioxidant enzyme activity of superoxide dismutase, peroxidase and polyphenol oxidase activity in both FH-1046 and YH-1898 . The oxidative stress reduction in infested plants after JA treatment was also evident from a fair decrease in MDA and H2O2 in both varieties. The SA and JA mediated genes expression was studied and it was found that in FH1046 maize cultivar, JA dependent genes, particularly marker genes PR1 and Lox5 were highly expressed along with TPS10 and BBT12. Whereas SPI, WRKY28, ICS and PAL were shown to be activated upon SA application. Evidently, both JA and SA elicited a robust defensive response within the maize plants against the voracious S. frugiperda, which in consequence exerted a discernible influence over the pest's developmental trajectory and physiological dynamics. A decrease in detoxification enzyme activity of the insects was observed after feeding on treated plants. Moreover, it was recorded that the survival and weight gain of FAW feeding on phytohormone treated maize plants also decelerated. In conclusion, FH-1046 was found to be more tolerant than YH-1898 against fall armyworm infestation and 1 mM JA was more effective than 1 mM SA for alleviation of fall armyworm stress. Therefore, it was inferred that phytohormones regulated redox homeostasis to circumvent oxidative damage and mediate essential metabolic events in maize under stress. To our current understanding, this study is the very first presentation of induced resistance in maize against S. frugiperda with the phytohormonal application (JA and SA).

Mitigation of drought-induced stress in sunflower (Helianthus annuus L.) via foliar application of Jasmonic acid through the augmentation of growth, physiological, and biochemical attributes

Drought stress poses a significant threat to agricultural productivity, especially in areas susceptible to water scarcity. Sunflower (Helianthus annuus L.) is a widely cultivated oilseed crop with considerable potential globally. Jasmonic acid, a plant growth regulator, plays a crucial role in alleviating the adverse impacts of drought stress on the morphological, biochemical, and physiological characteristics of crops. Experimental detail includes sunflower varieties (Armani Gold, KQS-HSF-1, Parsun, and ESFH-3391), four drought stress levels (0, 25%, 50%, and 75% drought stress), and three levels (0, 40ppm, 80ppm) of jasmonic acid. The 0% drought stress and 0ppm jasmonic acid were considered as control treatments. The experimental design was a completely randomized design with three replicates. Drought stress significantly reduced the growth in all varieties. However, the exogenous application of jasmonic acid at concentrations of 40ppm and 80ppm enhanced growth parameters, shoot and root length (1.93%, 19%), shoot and root fresh weight (18.5%, 25%), chlorophyll content (36%), photosynthetic rate (22%), transpiration rate (40%), WUE (20%), MDA (6.5%), Phenolics (19%), hydrogen peroxide (7%) proline (28%) and glycine betaine (15–30%) under water-stressed conditions, which was closely linked to the increase in stomatal activity stimulated by jasmonic acid. Furthermore, JA 80 ppm was found to be the most appropriate dose to reduce the effect of water stress in all sunflower varieties. It was concluded that the foliar application of JA has the potential to enhance drought tolerance by improving the morphological, biochemical, and physiological of sunflower.

Salicylic acid and jasmonic acid-mediated different fate of nickel phytoremediation in two populations of Alyssum inflatum Nyár.

This study investigates Ni phytoremediation and accumulation potential in the presence of salicylic acid (SA) (0, 50 and 200 μM) and jasmonic acid (JA) (0, 5 and 10 μM) in two populations of Alyssum inflatum under various nickel (Ni) doses (0, 100 and 400 μM). By measuring Ni levels in the shoots and roots, values of bioaccumulation coefficient (BAC), biological concentration factor (BCF) and translocation factor (TF) were calculated to quantify Ni accumulation and translocation between plant organs. Additionally, the amounts of histidine (His), citric acid (CA) and malic acid (MA) were explored. The results showed that plant dry weight (DW) [in shoot (29.8%, 8.74%) and in root (21.6%, 24.4%)] and chlorophyll [a (17.1%, 32.5%), b (10.1%, 30.9%)] declined in M and NM populations respectively, when exposed to Ni (400 μM). Conversely, the levels of MA [in shoot (37.0%, 32.0%) and in root (25.5%, 21.2%)], CA [in shoot (17.0%, 10.0%) and in root (47.9%, 37.2%)] and His [in shoot (by 1.59- and 1.34-fold) and in root (by 1.24- and 1.18-fold)] increased. Also, in the presence 400 μM Ni, the highest accumulation of Ni was observed in shoots of M (1392 μg/g DW) and NM (1382 μg/g DW). However, the application of SA and JA (especially in Ni 400 μM + SA 200 μM + JA 5 and 10 μM treatments) mitigated the harmful impact of Ni on physiological parameters. Also, a decreasing trend was observed in the contents of MA, CA, and His. The reduction of these compounds as important chelators of Ni caused a decrease in root-to-shoot Ni transfer and reducing accumulation in the shoots of both populations. The values of phytoremediation indices in both populations exposed to Ni (400 μM) were above one. In presence of the SA and JA, these indices showed a decreasing trend, although the values remained above one (BAC, BCF and TF > 1). Overall, the results indicated that SA and JA can reduce phytoremediation potential of the two populations through different mechanisms.

Jasmonic acid and heat stress induce high volatile organic compound emissions in Picea abies from needles, but not from roots.

Plants emit diverse volatile organic compounds (VOCs) from their leaves and roots for protection against biotic and abiotic stress. An important signaling cascade activated by aboveground herbivory is the jasmonic acid (JA) pathway that stimulates the production of VOCs. So far it remains unclear if the activation of this pathway also leads to enhanced VOC emissions from conifer roots, and how the interplay of above- and belowground defenses in plants are affected by multiple stressors. Therefore, we simultaneously analyzed needle and root VOC emissions of Picea abies saplings, as well as CO2 and H2O fluxes in response to aboveground JA treatment, heat stress and their interaction in a controlled climate chamber experiment. Continuous online VOC measurements by PTR-TOF-MS showed an inverse pattern of total needle and root VOC emissions, when plants were treated with JA and heat. While needle sesquiterpene emissions increased nine-fold one day after JA application, total root VOC emissions decreased. This was mainly due to reduced emissions of acetone and monoterpenes by roots. In response to aboveground JA treatment, root total carbon emitted as VOCs decreased from 31% to only 4%. While VOC emissions aboveground increased, net CO2 assimilation strongly declined due to JA treatment, resulting in net respiration during the day. Interestingly, root respiration was not affected by aboveground JA application. Under heat the effect of JA on VOC emissions of needles and roots was less pronounced. The buffering effect of heat on VOC emissions following JA treatment points towards an impaired defense reaction of the plants under multiple stress. Our results indicate efficient resource allocation within the plant to protect threatened tissues by a rather local VOC release. Roots may only be affected indirectly by reduced belowground carbon allocation, but are not involved directly in the JA-induced stress response.

The JA-OsJAZ6-DELLA module controls the tillering and drought stress response in rice

Jasmonic acid (JA) plays crucial functions during plant growth and stress response, but its roles and regulatory mechanism in plant branching remain largely unknown. Rice basal branching (tillering) is an essential agronomic trait that affects crop production. Here, we report that OsJAZ6, the repressor of JA signaling, negatively modulates rice tillering and drought stress tolerance. Loss-of-function mutants of OsJAZ6 exhibit a significant increase in tiller number, while OsJAZ6ΔJas-overexpression lines produce fewer tillers than wild-type plants. Further investigations show that function loss of OsJAZ6 promotes the tiller bud growth rather than formation. Mechanistic studies show that OsJAZ6 interacts with rice DELLA/SLR1 (SLENDER RICE 1), a transcription repressor of gibberellin (GA) signaling, and the interaction promotes SLR1 degradation, which further facilitates the degradation of rice tillering regulator MOC1 (MONOCULM 1), thereby inhibiting the tiller bud growth. In agreement, the slr1 mutant exhibits fewer tillers than wild type. Consistently, application of JA promotes the growth of tiller bud and thus increases the tiller number, while GA treatment results in opposite result. Meanwhile, osjaz6 mutants display enhanced drought tolerance, coupled with increased JA sensitivity, while the slr1 mutant shows the reverse behavior. Collectively, our data demonstrate that OsJAZ6 negatively modulates rice tillering as well as drought stress tolerance by destabilizing SLR1 protein. Our data shed light on the regulatory mechanism of controlling the tiller development and drought stress response in rice by the JA-OsJAZ6-SLR1 module.

Does jasmonic acid mitigate the adverse effects of salt stress on wheat through the enhancement of ascorbate biosynthesis and the induction of glutamate dehydrogenase activity?

AbstractBackgroundSalt stress is one of the most common abiotic stresses, reducing plant growth and productivity. Thus, the development of suitable management practices to minimize the deleterious effects of salt stress has become necessary.AimsThis study was conducted to investigate the possible mechanisms underlying salt tolerance conferred by jasmonic acid (JA).MethodsSalt‐stressed wheat seedlings were supplemented with 1 mM JA and/or 1 mM ibuprofen (IBU), an inhibitor of endogenous JA biosynthesis, in the culture medium.ResultsThe obtained results showed that salt stress significantly decreased shoot and root dry weight production and relative water contents. This was associated with a noteworthy reduction in leaf and root ascorbate (AsA) concentrations, as well as glutamine synthetase (GS), glutamate synthase (GOGAT), and glutamate dehydrogenase (GDH) activities. Exogenously supplied JA did not affect GS and GOGAT activities in leaves and roots of salt‐treated seedlings. However, noticeable enhancements were observed in growth, AsA concentrations, as well as GDH activities. Likewise, the inhibition of JA biosynthesis by IBU application was accompanied by a significant decrease in seedlings’ growth associated with a noticeable reduction in AsA concentrations and GDH activities. The decreases in growth and GDH activities were also obtained following inhibition of AsA biosynthesis by lycorine (Lyc) application. By contrast, increased GDH activities and enhanced growth were obtained following exogenous AsA supplementation, with or without JA biosynthesis inhibition.ConclusionsThe findings implied that exogenous JA enhanced AsA biosynthesis and induced GDH activity, which further promoted the growth of wheat seedlings in salt‐stressed conditions. Therefore, the stimulation of AsA biosynthesis and GDH activity through JA application in the rhizosphere may be suggested as a vital strategy for strengthening the salt tolerance of wheat plants, at least at the seedling stage.

Foliar jasmonic acid application reduces Cd and As accumulations in rice grains by regulating physiological, biochemical, and ROS scavenging attributes

The remediation of soil contaminated with cadmium (Cd) and arsenic (As) has consistently been a complex issue. Foliar application of jasmonic acid (JA) could be a promising agronomic practice for reducing heavy metal accumulations. However, the combined reduction effects and mechanisms of Cd and As in rice through foliar JA application have not been fully explored. In this study, a pot experiment was conducted to investigate rice yield, Cd and As accumulations and translocations, photosynthesis, and ROS-scavenging attributes in Huanghuazhan (HHZ) and Huarun No.2 (HR). The results revealed that 1 μM JA treatment significantly decreased the concentrations of Cd (by 34.6% in HHZ and 38.3% in HR) and As (by 30.8% in HHZ and 40.8% in HR) in the grains, and increased the percentage of filled-grain and 1000-grain weight in HHZ. The structural equation model (SEM) indicated that grain Cd was directly and positively affected by panicle Cd and leaf sheath Cd, while grain As was directly and positively affected by panicle As, leaf blade As and leaf sheath As. JA application enhanced the net photosynthetic rate and chlorophyll content (both a and b). Additionally, it scavenged levels of H2O2 and O2.-, reduced lipid peroxidation damage by promoting the activities of antioxidant enzymes and altering the cellular redox status in the flag leaves of rice. Overall, these results suggest that foliar JA application of could be an effective strategy for preventing Cd and As accumulations in rice grains in paddy soils with low to medium contamination risks.

Transcriptomic and physiological analyses reveal that jasmonic acid and abscisic acid coordinately regulate cold stress response in Myriophyllum aquaticum

Myriophyllum aquaticum, renowned for its ability to purify aquaculture wastewater, faces a significant challenge due to its susceptibility to cold stress. However, the molecular mechanisms underlying M. aquaticum's response to cold stress remain poorly understood. In this study, we unraveled the molecular mechanisms governing M. aquaticum's response to cold stress through transcriptome sequencing and physiological analyses. Our investigation revealed 12,684 differentially expressed genes during cold stress. Gene ontology and KEGG analyses demonstrated the involvement of plant hormone signaling and transcriptional reprogramming related genes in M. aquaticum's response to cold stress. Further investigations highlighted the role of jasmonic acid (JA) and abscisic acid (ABA) in M. aquaticum's cold acclimation. Firstly, cold stress significantly increased endogenous levels of JA and ABA in M. aquaticum plants. Secondly, the transcript levels of several crucial JA and ABA signaling genes were prominently elevated, as shown by expression profiling and qRT-PCR analyses. Thirdly, the application of exogenous JA or ABA effectively mitigated foliar damage and improved cold tolerance in M. aquaticum plants. Furthermore, the expression of JA and ABA biosynthesis and signaling genes was significantly upregulated in JA- or ABA-pretreated plants when exposed to cold stress. Collectively, our findings provide evidence that JA and ABA contribute to the cold acclimation of M. aquaticum plants. Our research provides insights into the molecular mechanisms underlying cold acclimation of M. Aquaticum plants and presents a novel strategy to improve their cold tolerance, thereby expanding their potential application in phytoremediation efforts in high latitude areas.

DETERMINATION OF THE EFFECT OF DIFFERENT DOSES OF JASMONIC ACID APPLICATIONS ON ALLEVIATING SALT STRESS IN TOMATO PLANTS WITH PHYSIOLOGICAL PARAMETERS

Salt stress is one of the most important abiotic stress factors that limit productivity in crop production due to climate change, whose effects have been felt more clearly in the world in recent years, and incorrect applications in agricultural soils. Research in plant production in saline soils, based on alleviating the effects of stress through applications to plants or soil, has gained momentum in recent years. In our study, we aimed to demonstrate that foliar jasmonic acid application to tomato plants alleviates the effects of salt stress with physiological parameters. Two tomato genotypes, sensitive to salt stress (TOM 106) and tolerant (TOM 23), determined in previous studies on abiotic stress, were used as plant materials. These two genotype selections were chosen to determine how close jasmonic acid brings the sensitive genotype to the tolerant genotype in salt stress. Salt dose is 100 mM and Control (0mM), jasmonic acid doses are; It was applied as 0, 20, 30 and 40 μM. The experiment carried out in pots was carried out under controlled conditions. Plant growth parameters (plant fresh and dry weight, stem diameter and plant length) and physiological parameters (such as leaf water potential, leaf osmotic potential, photosynthetic rate, transpiration rate, internal CO2, stomatal conductivity, chlorophyll) were measured at regular intervals. Jasmonic acid applications created a statistically significant difference. As a result, it was determined that 20 and 30 μM jasmonic acid applications were more effective in reducing salt stress damage.

Detection and Estimation of Endogenous Jasmonic Acid and Salicylic Acid in Potato Genotypes Imposed with Defense Modulators Using High Performance Liquid Chromatography

Jasmonic Acid (JA) and Salicylic Acid (SA) are pivotal signaling molecules involved in the complex network of plant defense mechanisms. Enhancing the levels of JA and SA through exogenous application or genetic manipulation has shown promising results in bolstering plant resistance to a wide range of diseases. This study investigates the effects of JA, SA and Compost Tea (CT) treatments on the endogenous JA and SA responses of four distinct potato genotypes-KH (Kufri Himalini, Solanum tuberosum), KJ (Kufri Jyothi, Solanum tuberosum), AC4 (Solanum sparsipillium) and AC6 (Solanum spegzinii). High-Performance Liquid Chromatography (HPLC) analysis was conducted to determine endogenous detectable levels of JA and SA defence phytohormones. The absorption spectra showed peak absorptions at 295 nm and 325 nm for JA (25 µg ml-1) and SA (10 µg ml-1) respectively. Retention times of JA and SA were determined to be RT-3.74 and RT-2.86 min respectively. The genotypes were subjected to various concentrations of JA and SA, and their respective impacts on endogenous JA and SA were measured. Genotype-specific responses were evident, with all genotypes displaying distinct sensitivities with respect to endogenous detectable JA in CT (KH-15.42 µg ml-1, KJ-133.67 µg ml-1, AC4-10.36 µg ml-1, AC6-7.92 µg ml-1), JA (KH-83.03 µg ml-1, KJ-184.14 µg ml-1, AC4-286.95 µg ml-1, AC6-9.2 µg ml-1) treatments while no detectable JA and SA was observed in Control, SA and JA+SA combined treatments. JA could enhance higher amount of detectable endogenous JA than CT treatment. The application of JA and SA enhancement could demonstrate success in various other crops rendering resistance against diseases in an eco-friendly approach.

The Effect of Organic Fertilization and Jasmonic Acid on the Morphological, Quantitative, and Chemical Parameters of Okra (Abelmoschus esculentus L.) variety Hussainawiya

A study was conducted in a field belonging to the Najaf Agriculture Directorate/Najaf/Iraq during the spring growing season of 2021. The study aimed to analyze the response of okra variety Hussainiya for two factors. The first studied factor was three levels of DPW (decomposed palm waste), including 0, 16, and 32 tonha-1, while the second factor was three levels of a foliar application of Jasmonic acid, including 0, 15, and 30 mgL-1. Randomized Complete Block Design (RCBD) was used to model the factorial experiment with three replications, and the Least Significant Differences (LSD) were selected to compare the means at the probability level of 0.05. The results showed the significant superiority of organic fertilization treatment of DPW at the level of 32-ton ha-1 compared with control treatments in the studied parameters, recording the highest value of the plant height, total number of leaves, total leaf area, dry weight of the vegetative system, number of fruits per plant, the yield of one plant, total yield, the percentage of nitrogen in leaves, the total chlorophyll percentage, and the total soluble carbohydrates in fruits. The foliar application of 30 mg. L-1 Jasmonic acid gave significantly higher values for the above indicators than control treatments. The interaction between the application of 32 tons. ha-1 DPW and 30 mg L-1 Jasmonic acids showed significant superiority over other treatments in all studied indicators. These indicators were plant height 131.66 cm, total number of leaves 42.55 leaves plant-1, total leaf area 1.66 m2plant-1, dry weight of the vegetative system 95.48 g plant-1, fruits number 77.15 fruit plant-1, yield of one plant 884.75 g plant-1, total yield 56.17 tons. ha-1, nitrogen in leaves 2.262%, total chlorophyll in leaves 80.91 mg.100 g-1FW, and carbohydrates in fruits 20.33%. While the interaction between non-fertilized plants sprayed with water only recorded significantly the lowest value of these indicators, which scored 77.10 cm, 20.36 leaf plant-1, 0.59 m2plant-1, 54.11 g plant-1, 47.23 fruit plant-1, 237.42 g plant-1, 15.07-ton ha-1, 1.351%, 47.45 mg.100 g-1 fresh weight, and 6.77% respectively. Keywords: Abelmoschus plant; decomposed palm waste; Jasmonic acid; okra, Organic fertilizer; yield indicators.

English

Application of untreated wastewater for vegetable production in peri-urban areas enters into the food chain leading to compromised human health. The present study was planned to evaluate the potential of cadmium (Cd) tolerant bacterial strains in combination with foliar application of Jasmonic acid (JA) under Cd stress. The Cd tolerant bacterial strains were isolated from wastewater and characterized for the production of exopolysaccharides (EPS), siderophore, and indole acdetic acid (IAA) under in vitro studies. The four most efficient strains SS5, SS7, SS8, and SS10 were selected based on growth-promoting traits and further evaluated with different levels of JA (20 μmol L-1 and 40 μmol L-1) in jar trial. Cauliflower (hyperaccumulator) was used as a test crop with Cd levels (0 and 150 mg kg-1). Our results depicted that the use of consortium (SS7+SS8) along with a foliar application of JA (40 μmol L-1) significantly improved shoot dry weight (15.5%), root dry weight (28.4%), shoot length (23.7%), root length (37%), superoxide dismutase (29.8%), peroxidase dismutase (29.7%), catalase (31.7%) and POX (29.2%). However, 29 and 26% reduction in Cd concentration in shoots and roots was observed, respectively. It was concluded that the Klebsiella strains SS7 and SS8 with foliar application of JA is a potential biofertilizer and a phyto-stabilizer for metal-contaminated soils and recommended to reduce the Cd toxicity among crop plants.

Boosting Drought Resistance in Pepper (Capsicum annuum L.) with the Aid of Arbuscular Mycorrhizal Fungi and Key Phytohormones

Drought is a primary abiotic stressor that markedly impairs pepper growth and quality. This study aimed to investigate the effects of foliar applications of phytohormones, including salicylic acid (SA), jasmonic acid (JA), and root application of arbuscular mycorrhizal fungi (AMF), on severe and moderate drought stress of 38-day-old ‘Anemon F1’ pepper plants. The results showed that drought stress led to a considerable decrease in plant growth parameters, nutrient uptake, leaf water content, and chlorophyll content, and it increased leaf temperature, phenolic and flavonoid contents, and antioxidant enzyme activity. Nevertheless, the combined application of AMF with SA and JA demonstrated substantial synergistic effects, resulting in a notable improvement in the ability to alleviate the detrimental impacts of drought stress. Furthermore, the combined application of AMF and phytohormones exhibited a stronger effect on drought stress compared with the individual application of AMF or phytohormones alone. The application of AMF+SA and AMF+JA not only improves the availability of essential nutrients but also leads to an increase in fresh shoot weight, relative water content, leaf area, and chlorophyll and antioxidant capacity. Consequently, the combined application of SA and JA with mycorrhiza emerged as a promising treatment for enhancing pepper growth under drought-stress conditions. The positive results observed in pepper cultivation through the combined use of phytohormones and mycorrhizae in regions with limited water availability emphasize the importance of investigating the effectiveness of similar approaches in other agricultural crops.

Transcription Factor and Zeatin Co-Regulate Mixed Catkin Differentiation of Chinese Chestnut (Castanea mollissima)

Castanea mollissima is an important monoecious fruit crop with high economic and ecological value in China. However, its yield is restricted by an imbalanced ratio of male and female flowers for chestnut production. To address this issue, we examined the morphology of bisexual flower organs, measured the levels of endogenous hormones in the flowers, profiled gene expression related to plant hormone biosynthesis and signaling pathways and transcription factors, and investigated the effects of exogenous jasmonic acid (JA) and zeatin (ZT) hormone application on flower development in C. mollissima ‘Tanqiao’. Morphological studies indicated that the development of male and female flowers can be divided into nine and eight stages, respectively. Male flowers contained higher levels of gibberellic acid (GA3) and abscisic acid (ABA) than female flowers, whereas female flowers had higher levels of JA and ZT. The analysis of the Kyoto encyclopedia of genes and genomes (KEGG) pathways revealed that the major significant enrichment pathways of differentially expressed genes (DEGs) consisted of plant hormone signal transduction and zeatin biosynthesis. Through time-series analyses, we screened 3 genes related to jasmonic acid biosynthesis and signal transduction and 21 genes related to zeatin biosynthesis and transduction. Among these genes, only the gene family LOG, related to zeatin biosynthesis, was highly expressed in female flowers. This result indicated that LOG may be the core gene hormone family involved in regulating female flower development. However, a weighted gene co-expression network analysis (WGCNA) suggested that IDD7 was the core gene involved in regulating female flower development. The results of exogenous hormone application indicated that zeatin could greatly increase the quantity of fertile female flowers, but JA was not significant. These findings demonstrated that zeatin and transcription factors were crucial regulators in the formation of female flowers in C. mollissima.