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L-Proline (l-Pro) is a non-essential amino acid which, in high concentrations, can cause neurological problems including seizures, although the causative mechanism for this is unclear. Here, we studied the impact of physiological levels of proline on brain energy metabolism and investigated the metabolism of l-Pro itself, using the cortical brain tissue slice and stable isotope labelling from [1-13 C]glucose and [1,2-13 C]acetate detected by NMR spectroscopy and LCMS. l-Pro was actively taken up by the slices and significantly reduced the total metabolic pools of all measured metabolites with glutamine the least affected, while reducing net flux of 13C into glycolytic byproducts (lactate and alanine). Conversely, net flux into Krebs cycle intermediates was increased, suggesting that L-Pro at lower concentrations was driving increased mitochondrial activity in both neurons and glia at the expense of glycolysis and metabolic pool sizes. As there was no evidence of metabolism of [1-13 C] l-Pro in slices under normo-glycemic conditions, the effect of proline on metabolism was not due to displacement of metabolites by added l-Pro. Comparison of the metabolic fingerprint generated by l-Pro in slices metabolizing [3-13 C]pyruvate with that generated by ligands active in the GABAergic system suggested that l-Pro may engender effects similar to that of the inhibitory neurotransmitter and metabolite γ-aminobutyric acid (GABA), in line with previous suggestions that l-Pro may be a GABA mimetic in addition to its role as a modulator of mitochondrial metabolism. [ABSTRACT FROM AUTHOR]

Apple is a commercially important fruit produced in Iran but due to water scarcity most of the orchards are irrigated with saline waters in arid and semi-arid regions of the country. Recent studies show that magnetization of irrigation water may decrease the adverse effects of salinity on some plants. In order to study the responses of apple seedlings to magnetization of saline water the M7 and MM106 saplings grafted on Golden Delicious rootstock were irrigated with saline water of 0, 40 and 80 mM NaCl exposed to a magnetic field 0, 0.1 0.2 Tesla. Saline water increased the Na+ content of the roots and leaves, hydrogen peroxide and electrolyte leakage of the cells, and decreased the quantum yield, K+ and Ca2+ contents of the root and leaf, relative water content and SPAD index of the saplings. However, the proline, soluble sugars, and phenolics contents, and the activity of catalase, peroxidase, superoxide dismutase and polyphenol oxidase enzymes were increased in saplings irrigated with magnetic water by 70.1%, 105.76%, 72.18%, 183.74%, 107.31%, 11.22% and 104.42%, respectively. Furthermore, all of these parameters were significantly enhanced in response to irrigation with a magnetized non-saline water. Both cultivars showed similar responses to magnetic field treatment. Our results demonstrate that magnetic field exposure ameliorates the adverse effects of saline water by enhancing plant antioxidant systems, water absorbance capacity, photosynthetic activity and absorbance rate of K+ and Ca2+ while decreasing the absorbance rate of Na+. The best results for magnetization treatment were obtained with 0.2 Tesla. [ABSTRACT FROM AUTHOR]

Proline is a major substrate in collagen biosynthesis and is required for collagen molecule formations. However, detailed explanations of the molecular basis through which proline functions in collagen biosynthesis have yet to be provided. Thus, genome-wide screening was employed to elucidate these in the pre-osteoblastic MC3T3-E1 and human periodontal ligament fibroblast (hPDLF) cell lines. Indeed, both cell lines represent important sources for collagen biosynthesis and tissue regeneration in the dental region, specifically treating extracellular proline during cultivations. The altered gene expression patterns were identified, and the precise expression patterns were confirmed by microarray. Cell viability and osteogenic differentiation patterns were examined using a range of experimental methods, such as the MTS assay, ALP staining, ARS staining, and collagen (COL)-type1A ELISA. Overall, we revealed a cell line-specific function of exogenous proline in collagen biosynthesis during osteogenic differentiation conditions with the candidate signaling pathways. These putative signaling networks could represent plausible answers to understanding collagen biosynthesis for regenerating connective tissues such as skin, muscle, and bone. [ABSTRACT FROM AUTHOR]

Potato is cultivated all the year round in Pakistan. However, the major crop is the autumn crop which is planted in mid-October and contributes 80–85% of the total production. The abrupt climate change has affected the weather patterns all over the world, resulting in the reduction of the mean air temperature in autumn by almost 1.6 °C in Pakistan, which in turn, has adversely affected the crop performance and tuber yield. This trial, therefore, was conducted to optimize and evaluate the concentration of salicylic acid (SA) and potassium nitrate (KNO3) for inducing frost stress tolerance in an autumn-sown potato crop cv. Sutlej. The findings revealed that the foliar application of 0.5 mM SA significantly enhanced the growth, yield, fluorescent, and biochemical indices of potato plants outperforming 100 mM KNO₃ application in comparison with the control. This included increased plant height by 14% and 17.6%, leaf area index by 6.3% and 26.3%, shoot biomass by 15.4% and 46.2%, crop growth rate by 16.7% and 43.3%, average tuber weight by 8.2% and 23%, tuber diameter by 6.8% and 12.2%, tuber yield by 26.1% and 46.3%, leaf angle by 16.2% and 21.6%, quantum yield of photosystem II by 20.6% and 28.2%, photosynthetically active radiations by 20.5% and 32.4%, chlorophyll content by 6.3% and 14.6%, leaf thickness by 14% and 29%, linear electron flow by 20% and 32.7%, O–2 by 6% and 14.4%, H2O2 by 11.7% and 27.6%, enzyme activities of catalase by 20.7% and 28.5%, superoxide dismutase by 28.6% and 28.5%, peroxidase by 8.3% and 13.5%, ascorbate peroxidase by 17.2% and 37.8%, total protein by 21% and 37%, proline by 36.2% and 114%, and phenolic content by 33% and 63.3% with a reduction in non-photochemical quenching by 12.7% and 29.6%, non-regulatory energy dissipation by 169.5% and 268.5%, and leaf electrolyte leakage by 57.5% and 180%, compared to KNO3 and the control, respectively. Based on the above findings, it can be concluded and recommended that 0.5 mM foliar spray of SA can be utilized on potato crop cv. Sutlej in frost-sensitive regions. However, the application rate of KNO3 needs to be optimized in order to use its maximal frost stress tolerance potential. [ABSTRACT FROM AUTHOR]

Bell peppers are highly sensitive to salt stress, posing significant challenges for sustainable vegetables production especially bell pepper under suboptimal climatic conditions. Given the economic importance of bell peppers, enhancing their tolerance to salinity stress is a critical research focus over period. Silicon (Si) and potassium (K) and are crucial elements that have potential to combat salt stress significantly. This study aimed to investigate influential role of Si and K fertilization on root growth, physiological response, and fruit yield of bell pepper under salt stress. The factorial experiment included six fertilizer doses (F0: control- recommended fertilizer dose (RDF); F1: RDF + K30 (35 kg ha−1 K); F2: RDF + 60 kg ha−1 Si (soil); F3: RDF + K30 (35 kg ha−1 K) + 60 kg ha−1 Si (soil); F4: RDF + 100 ppm Si (foliar), and F5: RDF + K30 (35 kg ha−1 K) + 100 ppm Si (foliar) and five water salinity levels (control- 0.54, 3, 6, 9, and 12 dS m−1). Results revealed that root morphological traits particularly root biomass, root-shoot ratio, root length and root length density were significantly improved by RDF + K30 (35 kg ha−1 K) + 60 kg ha−1 Si (soil), followed by RDF + K30 (35 kg ha−1 K) + 100 ppm Si (foliar). At 12 dS m−1 salinity level, about 53% and 55% higher root and shoot biomass was reported at RDF + K30 (35 kg ha−1 K) + 60 kg ha−1 Si (soil) in compare to control. Leaf proline accumulation was increased with rising salinity levels which maximized by 51% at RDF + K30 (35 kg ha−1 K) + 60 kg ha−1 Si (soil) followed by 43% increase at RDF + K30 (35 kg ha−1 K) + Si (foliar) over control at 12 dS m−1 salinity level. Enhanced fruit yield was observed with various Si and K fertilization combinations, where RDF + K30 (35 kg ha−1 K) + 60 kg ha−1 Si (soil) shown a 62% and 40% higher yield in compare to control at 9 and 12 dS m−1 salinity levels, respectively. Collectively, incorporating Si and K with standard fertilizer demonstrated synergistic effects, to mitigate the adverse impacts of salt stress through up-regulating root-shoot morphological traits, physio-biochemical attributes and fruit yield of bell pepper. [ABSTRACT FROM AUTHOR]

Soil contamination with toxic heavy metals [such as aluminum (Al)] is becoming a serious global problem due to the rapid development of the social economy. Although plant growth-promoting rhizo-bacteria (PGPR) are the major protectants to alleviate metal toxicity, the study of these bacteria to ameliorate the toxic effects of Al is limited. Therefore, the present study was conducted to investigate the combined effects of different levels of Acinetobacter calcoaceticus (5 ppm and 10 ppm) of accession number of MT123456 on plant growth and biomass, photosynthetic pigments, gas exchange attributes, oxidative stress and response of antioxidant compounds (enzymatic and nonenzymatic), and their specific gene expression, sugars, nutritional status of the plant, organic acid exudation pattern and Al accumulation from the different parts of the plants, which was spiked with different levels of Al [0 µM (i.e., no Al), 50 µM, and 100 µM] using aluminum sulfate [Al2(SO4)3] in wheat (Triticum aestivum L.). Results from the present study revealed that the Al toxicity induced a substantial decreased in shoot length, root length, number of leaves, leaf area, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, chlorophyll-a, chlorophyll-b, total chlorophyll, carotenoid content, net photosynthesis, stomatal conductance, transpiration rate, soluble sugar, reducing sugar, non-reducing sugar contents, calcium (Ca2+), magnesium (Mg2+), iron (Fe2+), and phosphorus (P) contents in the roots and shoots of the plants. In contrast, increasing levels of Al in the soil signifcantly (P < 0.05) increased Al concentration in the roots and shoots of the plants, phenolic content, malondialdehyde (MDA), hydrogen peroxide (H2O2), electrolyte leakage (EL), fumaric acid, acetic acid, citric acid, formic acid, malic acid, oxalic acid contents in the roots of the plants. Although, the activities of enzymatic antioxidants such as superoxidase dismutase, peroxidase, catalase, ascorbate peroxidase and their specific gene expression in the roots and shoots of the plants and non-enzymatic such as phenolic, favonoid, ascorbic acid, and anthocyanin contents were initially increased with the exposure of 50 µM Al, but decreased by the increasing the Al concentration 100 µM in the soil. Addition of A. calcoaceticus into the soil signifcantly alleviated Al toxicity effects on T. aestivum by improving photosynthetic capacity and ultimately plant growth. Increased activities of antioxidant enzymes in A. calcoaceticus-treated plants seem to play a role in capturing stress-induced reactive oxygen species as was evident from lower levels of MDA, H2O2, MDA, and EL in A. calcoaceticus-treated plants. Research findings, therefore, suggested that A. calcoaceticus application can ameliorate Al toxicity in T. aestivum seedlings and resulted in improved plant growth and composition under metal stress as depicted by balanced exudation of organic acids. [ABSTRACT FROM AUTHOR]

The metabolites gluconic acid, 5-ketogluconic acid, proline, and glutamic acid, produced by Pseudomonas reptilivora B-6bs, are industrially important, particularly in food and pharmaceutical sectors. However, producing these metabolites involves biotin supplementation to enhance yields, which is an expensive additive, and reducing its use can significantly lower production costs. Thus, This study aimed to enhance the production of gluconic acid, 5-ketogluconic acid, proline, and glutamic acid without biotin supplementation. To achieve this, a full factorial design was employed, varying agitation speed, glucose concentration, and temperature to determine the optimal conditions for metabolite production. Metabolite concentration was measured using spectrophotometric analysis and thin-layer chromatography (TLC), and the results were statistically analyzed using Minitab® 18. The findings demonstrate that Pseudomonas reptilivora B-6bs effectively produce gluconic acid (50.51 ± 0.035 g/L, YP/S: 0.917 g/g) and 5-ketogluconic acid (44.46 ± 0.23 g/L, YP/S: 0.947 g/g), along with proline (0.1727 ± 0.00085 g/L, YP/S: 0.00004 g/g) and glutamic acid (0.853 ± 0.142 g/L, YP/S: 0.013 g/g) without biotin supplementation. Optimal production was observed with a glucose concentration of 55 g/L. These findings provide a viable biotin-independent strategy for high-value metabolite production. This study contributes novel insights into cost-effective production processes, making it relevant to industrial applications. [ABSTRACT FROM AUTHOR]

The objective of our study was the collection and characterization of germplasm of different species of cucurbitaceae followed by its evaluation for drought tolerance. Characterization of two species of Luffa (9 genotypes), two species of Cucumis (12 genotypes), one species of Lagenaria (2 genotypes), one species of Cucurbita (2 genotypes), one species of Citrullus (one genotype) and one species of Momordica (one genotype) were done based on 15 characters including internodal length, days to first female flower opening, node number of first female flower etc. Among Luffa species, days to first female flower opening ranged from 28.66 to 42.00 days. In Cucumis callosus it ranged from 18.28 to 22.00 days.From this, twenty genotypes were evaluated for drought tolerance in a pot culture experiment.Higher proline content under water deficit was found in Momordica genotype IC-373784(212.69 ug g−1 of fresh wt.). Diphenyl picrylhydrazyl (DPPH) free radical scavenging activity was generally higher under water deficit and it was more pronounced in Cucumis melo var. momordica genotype AHS 82 (76.05%).The reduction in the photosynthesis rate was less in Cucumis melo var. momordica (from 11.73 to 10.85 µmol CO2 m−2 s−1). From this study, four genotypes of Cucumis melo var. momordica (IC-274017, IC-274007, IC-331085 and AHS 82) three genotypes of Cucumis melo var. callosus (IC-641436, AHK 119 and IC-351039) and one of Momordica charantia var. muricata (IC-373784) were identified as drought tolerant. [ABSTRACT FROM AUTHOR]

Drought stress poses a significant threat to crop productivity worldwide, necessitating innovative approaches to mitigate its adverse impact on crops. This study investigates the combined effects of methyl jasmonate and Pseudomonas fluorescens (P. fluorescens) under drought conditions in providing resilience to mustard plants (Brassica juncea) by bolstering antioxidative defense mechanisms, elevating secondary metabolite production, and promoting osmolyte accumulation. Under drought stress, mustard plants exhibited reduced growth and increased oxidative stress markers malondialdehyde and H2O2. However, the application of MeJA and P. fluorescens resulted in a substantial improvement in plant growth, as indicated by increased photosynthesis and shoots and root biomass with decrease in oxidative stress. This enhancement was attributed to an upregulation of antioxidative enzymes, including superoxide dismutase, catalase, and ascorbate peroxidase and glutathione reductase which collectively reduced reactive oxygen species levels and prevented oxidative damage. Furthermore, in combination they significantly enhanced the production of secondary metabolites and osmolytes enabling mustard plants to maintain cellular turgor and osmotic balance under drought conditions together with improved stress tolerance. In conclusion, these findings provide valuable insights into sustainable strategies for improving crop resilience to drought, with potential applications in agriculture to mitigate the adverse effects of climate change on crop production. [ABSTRACT FROM AUTHOR]

Seed hydration memory is the result of hydration and dehydration cycles (HD cycles) that occur naturally during seeds' imbibition in semiarid ecosystems. It is expressed through the improvement of germination and initial development, especially under water deficit. This study investigated the seed hydration memory expression in Senna spectabilis var. excelsa seedlings originating from seeds that underwent HD cycles and developed under water deficit. Seeds were subjected to 0, 1, 2 and 3 HD cycles and allowed to germinate in ideal growth conditions. After acclimatization, seedlings were subjected to water deficit treatments, which consisted of 15 days without watering, with a single watering event on the seventh day, and 15 consecutive days without watering. Subsequently, the seedlings were rewatered and underwent 48 h of recovery. Three assessments were performed: first after acclimatization, the second after both treatments, and the third after recovery. In each evaluation, morphological parameters (height, root length, stem diameter, and number of leaves), biomass accumulation, and proline concentration were analyzed. HD cycles promoted greater development of morphological parameters and greater accumulation of biomass and proline under water deficit. Phenotypic plasticity related to morphological characteristics and biomass accumulation was observed in seeds that were subjected to 1 and 2 HD cycles. Seeds that were submitted to 3 HD cycles promoted a higher proline concentration, suggesting seed hydration memory expression through phenotypic plasticity in physiological aspects. These responses to HD cycles allow the seedlings' development under water deficit, being able to overcome unpredictable conditions of water availability in semiarid ecosystems. [ABSTRACT FROM AUTHOR]

High salt concentrations pose a significant challenge to the efficiency of activated sludge (AS) in phenolic wastewater treatment. As a cellular osmoprotectant, proline (Pro) has the capacity to increase the salt tolerance of microbes in AS, hence improving the efficiency of phenolic wastewater degradation. Nevertheless, the precise mechanism behind this enhancement remains ambiguous. This study utilized short-time aerobic digestion (STAD) to examine the kinetics of phenol degradation (250–750 mg/L) by AS under high-salinity stress (2–8%), with the inclusion of Pro (115–575 mg/L) as an auxiliary agent. The process was optimized via response surface methodology (RSM), and the mitigating effect of Pro on microorganisms in AS subjected to salt stress was evaluated. The results demonstrated that the addition of 468 mg/L Pro substantially improved the ability of AS to withstand high-salinity wastewater with high phenol concentrations, which had a salinity of 5.1% and a phenol concentration of 531 mg/L. The addition led to a mitigation rate of the phenol degradation constant k0 of 38.59 ± 1.54%, resulting in enhanced degradation of chemical oxygen demand (COD), NH4+-N, and NO3−-N. In addition, the prolonged presence of Pro increased AS dehydrogenase activity (DHA) by 24.82% after 30 days. Microbial community analysis demonstrated that Pro promoted the proliferation of functional microorganisms such as Proteobacteria, Firmicutes, Acinetobacter, and Comamonas. These bacteria have essential functions in the elimination of phenol and organic matter, as well as the absorption of nitrogen. This study emphasizes the impact of Pro as a compatible solute in the treatment of high-salinity and high-phenol wastewater in the STAD process. [ABSTRACT FROM AUTHOR]

Proline, a multifunctional amino acid, plays a pivotal role in mitigating heat stress in maize. This review analyses proline's role in enhancing heat tolerance. Proline functions as an osmoprotectant, maintaining cellular hydration and turgor, and as an antioxidant, scavenging reactive oxygen species (ROS) to protect cellular components. These dual functions contribute significantly to cellular homeostasis under heat stress conditions. The biosynthesis and accumulation of proline in maize are regulated by complex genetic and metabolic pathways. Environmental cues, particularly heat stress, induce proline accumulation through the upregulation of biosynthetic genes and the suppression of catabolic pathways. Proline interacts with other molecular modulators, including glycine betaine, trehalose, ascorbate, glutathione, heat shock proteins (HSPs), spermidine, and abscisic acid (ABA), to collectively enhance heat stress tolerance. Moreover, proline is integrated into complex signaling networks, including ROS scavenging and calcium signaling pathways, to orchestrate cellular responses to heat stress. Understanding the regulatory networks governing proline's role in heat stress tolerance is crucial for developing maize varieties with improved resilience to climate change. By elucidating the molecular mechanisms underlying proline's multifunctional role, we can identify potential targets for genetic manipulation and biotechnological interventions to enhance crop performance under heat stress conditions. [ABSTRACT FROM AUTHOR]

In the first hours of development of salt-alkaline stress in the leaves of Kamenka variety spring wheat (Triticum aestivum L.), changes in the content of water, proline, organic (malic, citric, succinic) acids, and activity of peroxidases and catalase were studied. The two-factor experiment included variants with NaCl salinity (50, 100, 150, 200 mM), alkalinity (pH 7–10) and variants with combined effects of NaCl and pH. The separate and mutual effects of stress factors on the height and mass of the above-ground part of plants; the content of water, proline, and organic acids in leaves; and enzyme activity were established using a two-factor analysis of variance with the determination of the strength of influence according to Snedecor. After 24 and 48 h of stress exposure, changes in height and weight were minimal, and the strength of the influence of stress factors was 8–11%. Under the influence of separate and mutual action of salinity and pH, the water content in the leaves decreased, while the overall impact of stress factors ranged from 17 to 28%. Changes in leaf proline levels were relatively equally dependent on salinity, pH values, and the interaction of these factors; over the observation period, the overall effect of stress factors increased from 54 to 77%. The increase in the total content of citric, malic, and succinic acids was equally influenced by individual stress factors and their mutual effect; the total strength of their influence during the observation period increased from 66 to 99%. Catalase activity of wheat leaves decreased during the first observation period (1 h), then the enzyme activity gradually recovered. The catalase activity of leaves was influenced to a greater extent by the factor of high pH values. The increase in peroxidase activity of leaves depended equally on individual stress factors and their mutual action. During the observation period, the total effect of salt-alkaline stress factors on the peroxidase activity of leaves decreased from 93–97% (1 and 4 h) to 79% (24 h). It is concluded that, at the initial stage of development of salt-alkaline stress, the main adaptation processes include the accumulation of organic acids and the activation of peroxidases in wheat leaves. [ABSTRACT FROM AUTHOR]

Salt-sensitive crop varieties suffer from oxidative stress as a consequence of osmotic and ionic stresses in plants under salinity stress. This study is aimed at identifying the effects of riboflavin (RIB) application on uplifting rice growth under salinized soil condition. Two-week-old seedlings of IR29 (a salt-sensitive variety) were supplemented with 0.5 μM of RIB, and 50 mM of NaCl was supplied for 2 weeks, inducing salinized soil conditions. The results indicated that RIB pretreatment (RP) seedlings possessed higher plant biomass, and lower electrolyte leakage ration (ELR), hydrogen peroxide (H2O2) and malondialdehyde (MDA) concentrations, higher chlorophyll, magnesium (Mg), and iron (Fe) concentrations in the leaf blades, a higher proline concentration, and a lower Na+ concentration in the leaf blades. To further understand the mechanisms behind the difference in plant growth between the RP and non-RP seedlings, molecular analysis revealed that RP seedlings upregulated OsNHX1 and OsHKT1;5 expressions were observed in the roots of RP seedlings, regulating Na+ uptake through the transpiration stream and reducing Na+ concentration in the leaf blades. Collectively, these results suggest that RP is a potent method for improving plant growth under salinized soil conditions. [ABSTRACT FROM AUTHOR]

Zinc (Zn) deficiency is a serious problem for agriculture and human health. Under Zn deficient conditions, many physiological functions in plants are disturbed, and cellular homeostasis is badly affected. Under these circumstances, wheat crops produce fewer yields having low concentration of micronutrients in grains. In this modern era of nanotechnology, a possible way to achieve maximum plant growth in a sustainable manner is using nanoparticles (NPs). The present study was developed to observe the ameliorating effect of Zn nanoparticles (ZnNPs) as priming agents in wheat (Triticum aestivum L.) plants grown under saline circumstances. Five levels of ZnNPs: 0, 25, 50, 75, and 100 ppm, and two levels of salinity: 2 and 12 dS m−1, were studied. The mitigation of stress was seen in ZnNPs-applied wheat plants under salt stress, with a marked rise in total soluble sugars and total free amino acids. A significant decrease in pigment contents, total soluble proteins, and gas exchange characteristics was observed in the stress condition. Application of ZnNPs significantly improved the working of antioxidant enzymes, increased biochemical attributes, and helped regulate water relations and lipid peroxidation in wheat plants in a dose-dependent manner. It is worth mentioning that the application of ZnNPs at a rate of 100 ppm as a seed priming agent was observed to be the most distinct treatment in the accumulation of osmolytes and regulation of growth in wheat plants. [ABSTRACT FROM AUTHOR]

Pea is the third most widely grown leguminous vegetable crop globally. The crop is fairly easy to grow but is salt and drought-sensitive, limiting its yield. This study aimed to explore the morphological and biochemical responses of peas under salt stress and water-deficit stress. Three pea varieties (Climax, Green grass, Meteor) were subjected to different levels [5.4 mM (Control), 50 mM, 75 mM, and 100 mM of NaCl] of salt stress. The water-deficit stress was administered by watering 100%, 75%, and 50% of field capacity. Morphological parameters showed a significant reduction under salt and water-deficit stresses in all three varieties. The highest relative water content under various levels of both stresses was 38.3% which was significantly lower than the control treatment. Chlorophyll content index (CCI) declined significantly in all three varieties, however, Climax exhibited a noteworthy CCI of 43.7 at 100 mM salt treatment, significantly higher than Green grass (25.9 CCI) and Meteor (35.9 CCI) at the same treatment. Significant accumulation of proline content was observed under both stresses, where 100 g of fresh weight of Climax showed proline content as 0.043 mg against 100 mM salt and 0.040 mg against 50% water-deficit treatments. Similar trends were recorded for water-deficit stress, indicating a shared response to both stress types. These findings provide insights into the effects of salt and water-deficit stress on pea crops, specifically focusing on the role of proline. The insights gained may aid in developing strategies to mitigate these stresses for enhanced pea crop productivity. [ABSTRACT FROM AUTHOR]

Approximately 900 million hectares of farmland are destroyed by soil salinization, reducing global grain crop yield and quality. Although some current rice cultivars exhibit salt tolerance and high production yields, the exact mechanisms of their salt stress responses remain unclear. Hence, this study aims to elucidate the biochemical and biomolecular responses in different rice varieties, namely OM 9577 (salt-tolerant), OC 10 (moderately salt-tolerant), and Dai Thom 8 (salt-sensitive). The research findings indicate that increasing NaCl concentration leads to a decline in the fresh, dry mass of shoots and roots of all examined varieties (from 7.5 to 27% in OM 9577, OC 10; and from 16 to 54% in Dai Thom 8), as well as an increase in Na+ accumulation. OM 9577 and OC 10 accumulated higher levels of Ca2+, protein, proline, glycine betaine, sugars, and some monosaccharides (d-lyxofuranose, D-arabinose, ß-D-glucopyranose, ß-D-mannopyranose, D-galactofuranose) compared to Dai Thom 8. Transcript levels of some genes related to salt-tolerant mechanisms also have determined, including OsSOS1, OsNHX1, OsHKT1;4, OsHKT1;5, OsCaM, OsMAPKKK, OsCDPK, OsWAK, OsCML31, OsSOD, OsAOX1b, Os79, OsDUF26, OsWRKY26, OsWRKY62, OsAP2/ERF–58. The data demonstrated that transcript levels of some target genes were higher in OM 9577 and OC 10 than those in Dai Thom 8. Specifically, transcript levels of OsWRKY62, OsCML31, Os79, OsSOS1, OsHKT1:5, and OsCDPK were highest in OM 9577, while OsDUF26 and OsNHX1 transcript levels were highest in OC 10. These results offer potential biochemical and biomolecular markers for screening salt-tolerant rice cultivars and improving existing cultivars by transgenic or conventional breeding. [ABSTRACT FROM AUTHOR]

Salinity is one of the abiotic stress factors that affect plant physiology and cause various plant disorders. Thiourea, which consists of amino, thiol, and imino groups, is an antioxidant and growth regulator. The objective was to determine the antioxidant role of thiourea (0, 3, 6 mM) in attenuating the effects of salinity (0 mM, 50 mM, 100 mM NaCl) on growth, yield, and some biochemical compositions of flax (Linum usitatissimum L.) plants. Salt stress significantly reduced root and shoot length, root and shoot weight in dry and fresh matter, and yield components. In addition, salinity decreased photosynthetic pigments, total soluble sugar (TSS), and total free amino acids (TFAA) and suppressed ascorbate peroxidase (APX) and peroxidase (POX) activities, while proline and malondialdehyde (MDA) increased in stressed flax plants. Thiourea (TU) application improved all growth and yield characteristics of flax plants. TU increased photosynthetic pigment, APX, TSS, and TFAA while reducing proline and MDA. The differential accumulation of several proteins was reported under salt stress and TU-treatment. These proteins might be involved in the stress response and tolerance. Finally, foliar application of thiourea, especially at 6 mM, can counteract the effects of salinity on the growth and harvesting characteristics of flax plants by strengthening antioxidant defense mechanisms. [ABSTRACT FROM AUTHOR]

This study investigates the freezing tolerance and cold-induced changes in amino acid metabolism in three Triticeae species (rye, wheat, and barley) with varying levels of freezing tolerance. Freezing tests confirmed that rye exhibited the highest tolerance, while barley showed the highest sensitivity. Cold acclimation significantly increased total free amino acid levels, with wheat and barley showing nearly twice the accumulation compared to rye. The glutamate family of amino acids, particularly proline (Pro), γ-aminobutyric acid (GABA), and glutamine (Gln), displayed substantial increase during cold treatment. Pro levels were notably higher in freezing-tolerant wheat and barley genotypes, suggesting its role in osmotic stress mitigation. However, this correlation was absent in rye. Gene expression analysis revealed that cold-induced proline accumulation is likely regulated at the post-transcriptional level, particularly involving the P5CS gene. These findings highlight the species-specific metabolic adjustments and regulatory mechanisms underlying freezing tolerance in Triticeae species, emphasizing the central role of proline and glutamate family amino acids in cold acclimation. [ABSTRACT FROM AUTHOR]

Among different classes of osmolytes, proline is known for the prevention of protein aggregation. A limited number of studies have demonstrated the effectiveness of synthesized nano-osmolytes in stabilizing protein from aggregating. Because of the unknown characteristics of nanoparticles, it is essential to comprehend the effectiveness of recently synthesized nano-osmolytes in maintaining the stability of the protein. It is known that proline is effective at high molar concentrations and non-specific to various molecular targets for its biomedical applications. To enhance its efficiency, ZnO (zinc oxide), a known biocompatible nanoparticle, is used as proline-functionalized zinc oxide (ZnOP). Synthesis of ZnO and ZnOP was performed through the sol-gel method. Our results of chemical and denaturation studies suggest that conjugated ZnOP is perturbing more on the stability of the protein as compared to the equimolar mixture of ZnO and proline. Our biophysical studies reveal that ZnOP interacts more with the hydrophobic groups of BSA (bovine serum albumin) and acts as an intercalating agent to bind more BSA molecules to form higher aggregates. ZnO behaves as a denaturing agent whereas a mixture of ZnO and proline at higher temperature promotes fibrillation of the protein. Additionally, proline at 0.2 mM is effective against the unfolding of the protein at 1 M urea concentration, whereas ZnOP is perturbing more on the stability of protein than a mixture of ZnO and proline at the same condition. We conclude that ZnO could not be used as a biocompatible nano-carrier of proline osmolyte. [ABSTRACT FROM AUTHOR]

The impact of climate change on agricultural production is apparent due to declining irrigation water availability vis-à-vis rising drought stress, particularly affecting summer crops. Growing evidence suggests that zinc (Zn) supplementation may serve as a potential drought stress management strategy in agriculture. Field studies were conducted using soybean (Glycine max var. Saba) as a model crop to test whether foliar application of zinc oxide nanoparticles (ZnO-NPs) or conventional Zn fertilizer (ZnSO4) would mitigate drought-related water stress and improve soybean yield. Each fertilizer was foliar applied twice at a two-week interval during the flowering stage. Experiments were concurrently conducted under non-drought conditions (70% field capacity) for comparison. Results showed drought significantly reduced relative water content, chlorophyll-a, and chlorophyll-b in untreated control plants by 35.7%, 47.7%, and 41.4%, respectively, compared to non-drought conditions (p < 0.05). Under drought conditions, ZnO-NPs (200 mg Zn/L) led to 33.1% and 20.7% increase in chlorophyll-a and chlorophyll-b levels, respectively, compared to ZnSO4 at 400 mg Zn/L. Likewise, catalase, peroxidase and superoxide dismutase activities increased by 62.6%, 39.5% and 28.5%, respectively, with ZnO-NPs (200 mg Zn/L) under drought compared to non-drought conditions. Proline was significantly increased under drought but was remarkably suppressed (~ 54% lower) with ZnO-NPs (200 mg Zn/L) treatment. More importantly, the highest seed yield was observed with ZnO-NPs (200 mg Zn/L) treatment under drought (39% higher than untreated control) and non-drought (79.4% higher than control) conditions. Overall, the findings suggest that ZnO-NPs could promote seed yield in soybean under drought stress via increased antioxidant activities, increased relative water content, decreased stress-related proline content, and increased photosynthetic pigments. It is recommended that foliar application of 200 mg Zn/L as ZnO-NPs could serve as an effective drought stress management strategy to improve soybean yield. [ABSTRACT FROM AUTHOR]

Trichoderma spp. is primarily applied to manage biotic stresses in plants. Still, they also can mitigate abiotic stresses by the stimulation of antioxidative protective mechanisms and enhanced synthesis of secondary metabolites. The study optimized the conditions to enhance peptaibol production by novel Trichoderma spp, characterized and quantified peptaibol- alamethicin using HPLC and LC MS–MS. The present study investigated these isolates efficacy in enhancing growth and the associated physio-biochemical changes in black pepper plants under moisture stress. Under in vitro conditions, out of 51 isolates studied, six isolates viz., T. asperellum (IISR NAIMCC 0049), T. erinaceum (IISR APT1), T. harzianum (IISR APT2), T. harzianum (IISR KL3), T. lixii (IISR KA15) and T. asperellum (IISR TN3) showed tolerance to low moisture levels (5, 10 and 20%) and higher temperatures (35 and 40 °C). In vivo evaluation on black pepper plants maintained under four different moisture levels (Field capacity [FC]; 75%, 50%, and 25%) showed that the plants inoculated with Trichoderma accumulated greater quantities of secondary metabolites viz., proline, phenols, MDA and soluble proteins at low moisture levels (50% and 25% FC). In the present study, plants inoculated with T. asperellum and T. harzianum showed significantly increased growth compared to uninoculated plants. The shortlisted Trichoderma isolates exhibited differences in peptaibol production and indicated that the peptide might be the key factor for their efficiency as biocontrol agents. The present study also demonstrated that Trichoderma isolates T. harzianum and T. asperellum (IISR APT2 & NAIMCC 0049) enhanced the drought-tolerant capabilities of black pepper by improving plant growth and secondary metabolite production. [ABSTRACT FROM AUTHOR]

Water is an essential abiotic factor for seed imbibition process. Seeds of several Caatinga species have a physiological strategy known as seed hydration memory to mitigate the effects of irregular rainfall patterns in this environment. However, the mechanisms behind are not well understood. Therefore, our study aimed to evaluate the occurrence of water memory in Sarcomphalus joazeiro seeds through ecophysiological, biochemical and anatomical analyzes. The seeds were subjected to different cycles (0, 1, 2, and 3) of hydration (12 h) and dehydration (48 h)-HD, or continuous hydration (CH) for 183 h. The seedlings obtained of these seeds were subjected to different water suspension cycles. Our results showed that seeds subjected to HD cycles had greater germinability, higher emergence speed index, lower T50 values, and accumulated higher proline content. Seedlings from the 0, 1, and 2 seed HD cycles showed decreased net carbon assimilation (A) only when subjected to severe stress after 21 days of water deficit compared to the daily irrigated plants. While in seeds exposed to 3-HD cycles after 21 days of water deficit A did not change compared to control. Our results evidenced that seeds subjected to 3-HD cycles conferred the plants a greater tolerance to water deficit, proving the existence of seed hydration memory in Sarcomphalus joazeiro. [ABSTRACT FROM AUTHOR]

The longevity of cut flowers is associated with various physio-biochemical traits. To extend vase life (VL) of cut flowers, a wide range of chemical-based preservatives solutions have been used, which raise the concerns of human health and environmental pollution. This study explored the potential of using ascorbic acid (AsA) to naturally extend the VL of cut sword lily (Gladiolus grandifloras) 'White Prosperity' flowers. Fresh spikes were placed in vase solutions containing 1, 2, 3 and 4% AsA solutions, denoted as AsA1, AsA2, AsA3 and AsA4, respectively, as well as distilled water (DsW) as control. The AsA solutions prolonged the VL from 5.75 to 12.5 days. The treatment AsA4 significantly improved the relative fresh weight, floret diameter, the number of open florets, and chlorophyll contents. Ascorbic acid decreased oxidative stress (malondialdehyde and hydrogen peroxide) and boosted proline and total soluble proteins levels in cut sword lily, indicating a link with reduced water stress. AsA application improved phenols and sugars in the florets. Bacterial count was low in AsA-based vase solutions. Overall, AsA4 had the best performance with respect to VL and other associated traits. Given the encouraging outcomes of the ongoing research, AsA may be recommended as a viable postharvest treatment to extend the VL of sword lily. [ABSTRACT FROM AUTHOR]

Boron (B) is the most common trace element deficiency of cotton (Gossypium hirsutum L.) plantation in China. Whereas the narrow range of the deficiency and toxicity restrict the application of B, proline (Pro) mitigates many kinds of stress damage in plants, including B deficiency. How the pro-regulation of pro-metabolites affects plant growth, photosynthesis and leaf structure under boron (B) deficiency condition remains poorly understood. Here, this study investigates the effects of exogenous proline on the growth of Pro metabolites in cotton (E Kang 10) under B deficiency at different growth stages. We applied three Pro concentrations (0, 1.5 and 3 mg/L) with two B concentrations (0.1, 0.5 mg/L), with a total of six treatments. The addition of exogenous Pro at 1.5 mg/L significantly promoted the accumulation of B in leaves and increased the dry and fresh weight of various parts of the plant under low B stress. Additionally, the content of MDA was reduced, while the content of soluble protein increased in cotton plants under B0.1 treatment after the addition of Pro. Both 1.5 and 3 mg/L of Pro increased the ratio of chlorophyll a/b under B stress. In the late stage, the synthesis of Pro is mainly promoted by regulating the activities of Arg, P5CS, P5CR and ProDH. Under two B levels, the application of Pro significantly reduced the Pro content in roots at both growth stages, which was related to the decrease in Arg, Glu, GSA and P5CS activities. Additionally, exogenous applicable Pro has a better-alleviating effect on low B stress of cotton seedlings. [ABSTRACT FROM AUTHOR]

The objective of this study was to screen air pollution-induced stress in some plant species in the Sejzi industrial region (Isfahan, Iran). An assessment of APTI and other physiological and biochemical features of significant species in the area was conducted across three seasons: spring, summer, and autumn. The physiological and biochemical factors of the following species were evaluated: Limonium persicum, Atriplex lentiformis, Nitraria schoberi, Haloxylon persicum, Tamarix hispida, Zygophyllum atriplicoides, Karelinia caspica, and Prosopis farcta. The physiological factors assessed included acidity and relative humidity content, while the biochemical factors assessed included proline, sugar, ascorbic acid, and total chlorophyll. Subsequently, a thorough evaluation was carried out on the species under investigation to ascertain their biomonitors' capabilities and APTI. The study findings indicated that the species P. farcta, N. schoberi, and K. caspica consistently had high APTI values during the spring, autumn, and summer seasons, classifying them as tolerant plant species. Conversely, the observed traits showed significant fluctuations across the seasons. The investigation's findings indicate that the species L. persicum, N. schoberi, and K. caspica exhibit higher annual averages of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid compared to other species. The examination of the annual variation in the tolerance levels of plant species to pollution ranked from highest to lowest was as follows: N. schoberi, P. farcta, K. caspica, Z. atriplicoides, H. persicum, T. hispida, L. persicum, and A. lentiformis. Moreover, based on the annual average, the primary determinants that impact the APTI in the species being studied include ascorbic acid (35%), leaf acidity (19%), total chlorophyll content (35%), and relative humidity content (69%). Furthermore, a distinct and significant correlation was found between proline and sugar levels and the annual APTI values. Additionally, the species P. farcta had the highest API compared to other species. The study revealed the high potential of some plant species against air pollution induced stress which can be used in air and dust pollution management in the region. [ABSTRACT FROM AUTHOR]

The effects of exogenously applied ascorbic acid (AsA, 1 mM) and proline (Pro, 1 mM), were evaluated on the growth, nutritional behavior, some key biochemical attributes, oxidative damage indicators, osmolytes accumulation as well as antioxidant system in wheat seedlings (Triticum aestivum cv. Salammbô) grown in the presence of 100 mM NaCl. AsA or Pro supplementation ameliorated wheat seedlings' growth and increased parameters that were reduced by salinity. Relative water content, total chlorophyll, K+ and total carbohydrates contents as well as K+/Na+ ratio and root-to-shoot K+ translocation were significantly increased. Osmoprotectant contents were remarkably accumulated, whereas Na+ content and root-to-shoot Na+ translocation were significantly declined. Additionally, exogenous AsA or Pro application enhanced the antioxidant defense system components and insured better oxidative stress tolerance, as indicated by reduced H2O2 production and lipid peroxidation, resulting in an increased membrane stability index. Such effects were further enhanced following the simultaneous application of AsA and Pro, resulting in a better growth, as compared to single applications of these substances. Taken together, findings of this study provide strong arguments highlighting the potential synergy between exogenously applied AsA and Pro in mitigating the adverse effects of salt stress of wheat plants at the early seedling stage. [ABSTRACT FROM AUTHOR]

Hazelnuts are glycophytic and sensitive plants to salt, especially to chloride ion. However, the genotypes might be different in responses to salt stress. This search attempted to understand the behavior of four hazelnut commercial widely grown cultivars ('Segorb', 'Ronde de Piemant', 'Fertile de Coutard' and 'Negret') under salinity stress. The experimental four-year-potted plants were treated with four levels of NaCl (0, 30, 60, and 90 mM). Variations were found in the values of morphological and physiological indicators between the studied cultivars. The 'Fertile de Coutard' leaves contained the lowest accumulation of sodium (0.48%) and chloride (1.1%) of dry weight (DW)), a high potassium content (1.4% DW), the smallest decrease of Fv/Fm (15.85% at 90 mM K+/Na+ ratio (2.91% DW), the lowest decrease in the relative water content (RWC) (22.5%), the highest proline content (4 μmol g−1) of fresh weight (FW), and a low amount of lipid peroxidation (0.6 μmol g−1 FW) compared to other cultivars. On the contrary, 'Segorb' contained the highest chloride content (1.63% DW), and recorded the greatest decrease of Fv/Fm (45.12% at 90 mM NaCl) and K+/Na+ ratio (1.45% DW). Changes in the expression rate of the studied transcription factors (TF) were observed. The drought-responsive element binding (DREB) transcript level significantly increased after 12 h in 'Fertile de Coutard', and 72 h in 'Segorb'. The APETALA2/ethylene-responsive factor (AP2/ERF) transcript abundance reached the highest level after 72 h of treatment in 'Fertile de Coutard', while it did not change in 'Segorb'. Thus, our results indicate that the 'Fertile de Coutard' has the greatest potential to resilient salinity stress among the studied cultivars. [ABSTRACT FROM AUTHOR]

We report the detailed mechanistic insights of L-proline catalyzed, solvent-controlled, regioselective Mannich reaction. Different solvation models were employed to understand the formation of critical intermediates. The seminal difference in the nature of H-acceptor solvents and H-donor solvents leads to variation in the attachment site on the reactant molecule. Our calculations suggest that the H-acceptor solvent exhibits selective non-covalent interaction with α-hydrogen atoms of the iminium group, facilitating the reactivity at the more hindered site, which results in the formation of a branched isomer. On the other hand, the H-donor solvent preferentially binds to the carboxylate group, thus enabling the reactivity to proceed from the less hindered carbon chain, leading to a linear isomer. The above distinct interactions force a regioselective generation of enamines. Thus, the iminium ion's site-specific solvent interaction has been observed to cause a switch in the regioselectivity. These enamines subsequently react with cyclic ketone to produce Mannich base with excellent enantioselectivity (>99%ee). [ABSTRACT FROM AUTHOR]

Soil salinity is one of the most devastating environmental impediments that poses a significant threat to agricultural practices hamper crop productivity worldwide. In the present study, a total of thirty finger millet genotypes were examined through in vitro screening at varying sodium chloride concentrations (0, 75, 175, 275, and 375 mM). Based on the morphological characteristics, visual salt injury (VSI) and salinity susceptibility index (SSI), two tolerant (TRY–1 and ML–365), two moderately tolerant (GPU—48 and GPU—28) and two susceptible (VL–146 and Indaf–9) genotypes were shortlisted. Further, the greenhouse illustrated the experiment to assess physiological and biochemical response at the seedling stage by imposing sodium chloride concentrations (0 and 375 mM). The results revealed that TRY–1 was on par among all the studied genotypes that exhibited a significant increase (P < 0.05) in phenotypic (germination percentage, shoot length, root length, and seedling vigour index) biochemical characteristics (contents of total chlorophyll, proline, phenolic, and flavonoids) and antioxidant enzyme activities (SOD and CAT) under varying salinity regimes indicating a strong defense mechanism against salinity-induced oxidative and osmotic stress. In contrast, Indaf—9 exhibited a significant decrease in all the growth and physiological traits and an increment in MDA and H2O2 content compared to other genotypes. In Indaf—9, MDA increased by 184% whereas in TRY—1, it increased by 105%. In contrast, proline content was enhanced as maximum in TRY –1 (239%) compared to Indaf—9 (191%) from 0 to 375 mM sodium chloride concentration. Our findings were supported by extensive statistical analyses such as cluster analysis, correlation, and PCA, indicating key contributing traits involved in salinity stress tolerance. Therefore, this study may help select the salt-tolerant genotypes and contribute to sustainable agriculture by increasing food production in saline-prone agroecological zones. [ABSTRACT FROM AUTHOR]

We attempted to study the response of six rice cultivars, viz., BPT 5204, CR 1009, TRY 1, CO 50, Jodimattai, and CO 46, to salt stress under in vitro conditions. In this study, we report the highest relative growth rate (RGR) in BPT 5204 and TRY1, suggesting that these could maintain a higher relative fresh mass of the callus to survive salt stress. For regeneration frequency (RF), genotype TRY 1 registered the highest RF (35%) in the control (0 mM NaCl), but a significant reduction in RF (66%) was observed at 90, 120, and 150 mM NaCl. The genotypes CO 50, CR 1009, and BPT 5204 registered the lowest regeneration frequency (6.7%) and produced a moderate number of shoots. The biochemical nature of stress implies that proline content decreases in the control and progressively increases from 30 to 90 mM but gradually decreases with higher salt concentrations. The proline content was high for both tolerant (BPT 5204) and sensitive (CO-46) cultivars, implying that proline gives adaptiveness rather than growth. Our results provide unique insight into the antioxidant (catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD)) properties of callus culture. Antioxidants act as potential reactive oxygen species (ROS) scavengers and provide adaptive mechanisms to plants. The antioxidant enzyme activities increased progressively with increasing NaCl concentration in the medium, showing that antioxidants augment the stress and provide an adaptive mechanism. The genotypes BPT 5204 and TRY1 had a significant level of enzyme activities at 90, 120, and 150 mM NaCl treatment, whereas the other genotypes seemed to have reduced enzymatic activities. Hence, the genotypes BPT 5204 and TRY1 were better in their performance for the above parameters, which showed growth and biochemical homeostasis in response to salt stress. [ABSTRACT FROM AUTHOR]

The effect of exogenous administration of two concentrations of proline (10 and 20 mM) on postharvest values and chilling injury (CI) of 'Malaseh Saveh' pomegranate (Punica granatum L.) fruits was investigated during 90 days at 4 °C. Proline treatment attenuated CI symptoms and prevented membrane lipids peroxidation, and reduction of cell membrane integrity in treated fruits, which were represented by malondialdehyde and electrolyte leakage, respectively. Therewith, a higher amount of endogenous proline (352.48 µg g−1 FW) was perceived in 20 mM proline-treated fruits at the end of the cold storage time. Furthermore, proline treatment increased antioxidant capacity and antioxidant enzyme activity, namely ascorbate peroxidase, superoxide dismutase, and catalase, and also retained ascorbic acid amount at higher levels. This treatment decreased the activity of polyphenol oxidase and enhanced the phenylalanine ammonia-lyase activity which led to high accumulation of total phenol, flavonoids, and anthocyanin. All in all, exogenous application of proline, especially 20 mM concentration, as a safe, natural, and environment-friendly osmolyte substance, could alleviate harmful effects of CI and retain eating values of pomegranate fruits all over long-term postharvest and shelf life. [ABSTRACT FROM AUTHOR]

Understanding gene expression kinetics and the underlying physiological mechanisms in stress combinations is a challenge for the purpose of stress resistance breeding. The novelty of this study is correlating the physiological mechanisms with the expression of key target genes in tall fescue under a combination of various salinity and osmotic stress treatments. Four drought- and salt-responsive genes belonging to different crucial pathways evaluated included one transcription factor FabZIP69, one for the cytosolic polyamine synthetase FaADC1, one for ABA signaling FaCYP707A1, and another one for the specific Na+/H+ plasma membrane antiporter FaSOS1 involve in osmotic homeostasis. FaSOS1, FaCYP707A1, and FabZIP69 were induced early at 6 h after NaCl treatment, while FaSOS1 and FaCYP707A1 were transcribed gradually after exposure to PEG. However, stress interactions showed a significantly increased expression in all genes. Expression of these genes was positively correlated to Pro, SSs, IL, DPPH, and antioxidant enzyme activity and negatively correlated with RWC, total Chl, and MSI. Chemical analyses showed that tall fescue plants exposed to the combination of stresses exhibited increased quantity of reactive oxygen species (H2O2), EL and DPPH, and higher levels of antioxidant enzyme activities (CAT, and SOD), Pro, and SSs content, compared with control seedlings. Under dual-stress conditions, the expression of FabZIP69 was effective in controlling the expression of FaSOS1 and FaADC1 genes differently. [ABSTRACT FROM AUTHOR]

Drought stress, at different growth stages, causes substantial yield loss in major crops, thus, threatening global food security. Enhancement of drought stress tolerance in plants has been reported with the sole application of silicon (Si) and Zinc (Zn). However, the synergistic effects of their combined application and the exact mechanisms through which they enhance drought tolerance are still not fully understood. Therefore, the present study investigated the potential of Si and Zn to ameliorate drought stress in Eruca sativa (L.) and associated morphological and physio-biochemical mechanisms. The seeds were soaked in individual or combined Si (3 mM, from calcium silicate) and Zn (10 mM, from zinc sulfate) solutions for 8 h and 12 h. Water-primed and unprimed seeds were kept as control. Later, primed seeds were grown under various levels of drought viz. control (100% field capacity, FC) and 50% FC. Results revealed that drought stress significantly reduced growth traits, photosynthetic pigments, and reactive oxygen species and decreased antioxidative enzymes activities. Seed priming with Si and Zn increased seedling lengths, and their fresh and dry weights under drought stress with significantly higher values for the combined application of both. Moreover, Si and Zn-treated plants also showed a significant increase in chlorophyll pigments, i.e., chlorophyll and carotenoid contents in drought-exposed seedlings. Seed priming treatments improved drought-induced oxidative stress tolerance associated with higher activities of enzymatic and non-enzyme antioxidant activities and soluble sugar and proline contents. The results suggested that the combined application of Si and Zn serves as an appropriate treatment to increase the seedling growth, and physiological and biochemical attributes of E. sativa under drought stress conditions. [ABSTRACT FROM AUTHOR]

Heat stress poses a significant environmental challenge that profoundly impacts wheat productivity. It disrupts vital physiological processes such as photosynthesis, by impeding the functionality of the photosynthetic apparatus and compromising plasma membrane stability, thereby detrimentally affecting grain development in wheat. The scarcity of identified marker trait associations pertinent to thermotolerance presents a formidable obstacle in the development of marker-assisted selection strategies against heat stress. To address this, wheat accessions were systematically exposed to both normal and heat stress conditions and phenotypic data were collected on physiological traits including proline content, canopy temperature depression, cell membrane injury, photosynthetic rate, transpiration rate (at vegetative and reproductive stage and 'stay-green'. Principal component analysis elucidated the most significant contributors being proline content, transpiration rate, and canopy temperature depression, which exhibited a synergistic relationship with grain yield. Remarkably, cluster analysis delineated the wheat accessions into four discrete groups based on physiological attributes. Moreover, to explore the relationship between physiological traits and DNA markers, 158 wheat accessions were genotyped with 186 SSRs. Allelic frequency and polymorphic information content value were found to be highest on genome A (4.94 and 0.688), chromosome 1A (5.00 and 0.712), and marker Xgwm44 (13.0 and 0.916). Population structure, principal coordinate analysis and cluster analysis also partitioned the wheat accessions into four subpopulations based on genotypic data, highlighting their genetic homogeneity. Population diversity and presence of linkage disequilibrium established the suitability of population for association mapping. Additionally, linkage disequilibrium decay was most pronounced within a 15–20 cM region on chromosome 1A. Association mapping revealed highly significant marker trait associations at Bonferroni correction P < 0.00027. Markers Xwmc418 (located on chromosome 3D) and Xgwm233 (chromosome 7A) demonstrated associations with transpiration rate, while marker Xgwm494 (chromosome 3A) exhibited an association with photosynthetic rates at both vegetative and reproductive stages under heat stress conditions. Additionally, markers Xwmc201 (chromosome 6A) and Xcfa2129 (chromosome 1A) displayed robust associations with canopy temperature depression, while markers Xbarc163 (chromosome 4B) and Xbarc49 (chromosome 5A) were strongly associated with cell membrane injury at both stages. Notably, marker Xbarc49 (chromosome 5A) exhibited a significant association with the 'stay-green' trait under heat stress conditions. These results offers the potential utility in marker-assisted selection, gene pyramiding and genomic selection models to predict performance of wheat accession under heat stress conditions. [ABSTRACT FROM AUTHOR]

Proline is a unique amino acid in that its side-chain is cyclised to the backbone, thus giving proline an exceptional rigidity and a considerably restricted conformational space. Polyproline forms two well-characterized helical structures: a left-handed polyproline helix (PPII) and a right-handed polyproline helix (PPI). Usually, sequences made only of prolyl residues are in PPII conformation, but even sequences not rich in proline but which are rich in glycine, lysine, glutamate, or aspartate have also a tendency to form PPII helices. Currently, the only way to study unambiguously PPII structure in solution is to use spectroscopies based on optical activity such as circular dichroism, vibrational circular dichroism and Raman optical activity. The importance of the PPII structure is emphasized by its ubiquitous presence in different organisms from yeast to human beings where proline-rich motifs and their binding domains are believed to be involved in vital biological processes. Some of the domains that are bound by proline-rich motifs include SH3 domains, WW domains, GYF domains and UEV domains, etc. The PPII structure has been demonstrated to be essential to biological activities such as signal transduction, transcription, cell motility, and immune response. [ABSTRACT FROM AUTHOR]

Soybean is essential for food security worldwide and water restriction is a rising challenge for its production. In this scenario the use of natural sources such as Ascophyllum nodosum extracts (ANE) which contribute to the better adaptation of plants to environmental stresses, gains relevance. Nonetheless, understanding the metabolic effect of ANE according to the time of application could be better explored, such as, if the application before or during the stress occurrence can trigger different metabolic responses. Thus, this work aimed to identify the physiological and biochemical effects of foliar application of ANE at different times, in soybean plants subjected to water restriction. The experiment was carried out in pots with plants at the vegetative stage, subjected to foliar sprays of ANE in the following treatments: (i) application of ANE at adequate humidity with 80% of the substrate water holding capacity (WHC); (ii) application of ANE three days before the humidity reached 50% of the substrate WHC; (iii) application of ANE on the day that WHC reached 50% (established as drought stress condition); (iv) positive control without application of ANE and WHC 50%; (v) absolute control, without application of ANE and without water restriction. The results allow to point out that ANE application three days before drought stress improved nitrate reductase enzyme activity, chlorophyll and proline content, decrease lipid peroxidation and presented more effective improvement of peroxidase enzyme activity; while application at stress condition resulting in more effective reduction of stomata resistance, long term expressive proline content increment, more effective improvement of superoxide dismutase and catalase enzymes activity and reduce chlorophyll degradation. This works results also could help to answer some field practice questions, such as; it is worth applying ANE when plants are already under drought stress. Ascophyllum nodosum extracts (ANE) applied three days before drought stress (A) improved nitrate reductase enzyme activity (NR), proline (PR) and chlorophyll content (Chl), decreased lipid peroxidation (LP) and presented more effective improvement of peroxidase enzyme activity (POD). Application at stress condition (B) resulting in more effective reduction of stomata resistance (SR) and chlorophyll (Chl) degradation, long term proline content increment (PR), more effective improvement of superoxide dismutase (SOD) and catalase (CAT) enzymes activity. [ABSTRACT FROM AUTHOR]

We studied the effect of seed treatment with salicylic acid (SA, 100 μM) on seed germination, growth, the level of lipid peroxidation (LPO), and the functioning of a number of components of the antioxidant system in wheat plants (Triticum aestivum L.) Zlata variety grown with optimal (2 μM) or excess (1500 µM) zinc content in the root environment. It has been shown that excess zinc has an inhibitory effect on root and shoot growth and also enhances the accumulation of one of the indicators of LPO development: malondialdehyde (MDA). At the same time, the structural integrity of the membranes was maintained, as indicated by the absence of changes in membrane permeability, recorded by the yield of electrolytes. The activity of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), did not change under these conditions, but the activity of guaiacol-specific peroxidase (GPO) decreased. Treatment of seeds with SA at a concentration of 100 μM, which stimulates their germination, enhanced the negative effect of excess zinc on growth performance and MDA accumulation in wheat leaves. However, in this case, the yield of electrolytes did not increase, which is presumably due to an increase in the activity of SOD and GPO. Based on the data presented in the work and previously obtained, as well as an analysis of the literature, it was concluded that the response of plants to excess zinc in the external environment, like the reaction to other abiotic stresses, is not only multicomponent and multiechelon but also variable, depending on many factors and circumstances: the dose of exposure (zinc concentration and duration of its action), biological characteristics of the plant species (variety), their age condition, etc. Treatment of seeds with SA can change the nature of the plant’s response to the action of excess zinc, and the direction of these changes will, in turn, depend on the concentration of SA, the duration of its action, and the method of treatment. [ABSTRACT FROM AUTHOR]

Drought stress is one of the most important limitations in the production of agricultural products and especially horticulture in different parts of the world and Iran. The climate changes that have happened in the last few years, it is possible to provide sustainable production of grapes in water stress conditions by examining and selecting cultivars that tolerate to drought stress. For this purpose, an experiment from 2018 to 2022 in the form of split plots in the form of randomized complete blocks with 3 replications in garden conditions to investigate the effect of changes in soil water potential on the morphological, physiological and biochemical characteristics of grafted cuttings on cultivar traits Tolerant to sensitive 7 grape (Vitis vinifera L.) cultivars were carried out. The treatments included 7 selected grape varieties (‘Bidaneh Ghermez’, ‘Bidaneh Sefid’, ‘Rashe’, ‘Sahani’, ‘Kare Royeh’, ‘Moulai’, and ‘Chafte’) as the base and red quince cultivar as scion and three levels of drought stress including humidity. Agricultural (control), 75% (moderate stress) and 55% (severe stress) were based on agricultural moisture discharge. The results showed that with more severe water stress, the amount of proline, ABA, activity of catalase and peroxidase, the expression of CBF4, NCED3, and DHN1 genes increased, as well as the amount of total chlorophyll were decreased. In this experiment, the highest proline, abscisic acid, catalase, peroxidase, NCED3, CBF4 and DHN1 gene expression were observed in this experiment under severe stress treatment. In general, ‘Bidaneh Ghermez’ cultivar grafted on the rootstocks of ‘Chafte’, ‘Moulai’ and ‘Kare Royeh’ had a higher potential for tolerance to drought stress than other grafted combinations tested in most of the traits. [ABSTRACT FROM AUTHOR]

Cadmium (Cd2+) is a toxic heavy metal that is widespread throughout the environment. It is a subject of interest to environmental scientists because of its toxicity to plants, animals, and humans. The current work aims to evaluate the effects of Cd2+ on the production of phenolic compounds and morphological, physiological and biochemical responses of Lupinus albus L. plants exposed to Cd2+ at 0, 10, 20, 50, 100, and 150 μM CdCl2 for 7 days. Cd2+ induced negative effect on growth especially at the dose of 150 µM. Cd2+ also induced chlorosis and reduced photosynthetic activity. Besides, the metal increased the level of malondialdehyde (MDA). Under Cd2+ toxicity (50, 100, and 150 µM), the superoxide dismutase (SOD) and catalase (CAT) activities were increased or not significantly affected, while at 150 µM Cd2+ affected the activity of these enzymes. At the highest Cd2+ level (150 µM), proline and total polyphenol and flavonoid contents were markedly increased in leaves and roots of L. albus. Our results suggest that L. albus plants produced phenolic compounds with reducing capacity as a selective mechanism triggered by the highest activity of Cd2+. [ABSTRACT FROM AUTHOR]

Metabolic regulation occurs through precise control of enzyme activity. Allomorphy is a post-translational fine control mechanism where the catalytic rate is governed by a conformational switch that shifts the enzyme population between forms with different activities. β-Phosphoglucomutase (βPGM) uses allomorphy in the catalysis of isomerisation of β-glucose 1-phosphate to glucose 6-phosphate via β-glucose 1,6-bisphosphate. Herein, we describe structural and biophysical approaches to reveal its allomorphic regulatory mechanism. Binding of the full allomorphic activator β-glucose 1,6-bisphosphate stimulates enzyme closure, progressing through NAC I and NAC III conformers. Prior to phosphoryl transfer, loops positioned on the cap and core domains are brought into close proximity, modulating the environment of a key proline residue. Hence accelerated isomerisation, likely via a twisted anti/C4-endo transition state, leads to the rapid predominance of active cis-P βPGM. In contrast, binding of the partial allomorphic activator fructose 1,6-bisphosphate arrests βPGM at a NAC I conformation and phosphoryl transfer to both cis-P βPGM and trans-P βPGM occurs slowly. Thus, allomorphy allows a rapid response to changes in food supply while not otherwise impacting substantially on levels of important metabolites. A structural study shows that the enzyme βPGM uses an allomorphically controlled switch that accelerates proline isomerisation to alleviate the wastage of valuable metabolites while allowing the organism to react quickly to changes in food supply. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

The unique physicochemical properties of PEG-400 were imparted to (L)-prolinamide to afford a homogeneous, solvent-free, recyclable organocatalyst for scalable enantioselective aldol reaction between acetone and benzaldehyde to afford (R)-4-hydroxy-4-phenylbutan-2-one. The reaction was scaled up to afford 41 g of ketol in 95% yield and an ee of 91% using 30 mol% catalyst, 10 mol% trifluoroacetic acid (TFA), and 135 equivalent moles of acetone with respect to benzaldehyde. The catalyst was recycled 4 times with no obvious loss of activity. The role of PEG is discussed at the molecular level. This type of catalyst may provide new possibilities for the so-far-thwarted attempts at large-scale application of proline organocatalysis to asymmetric aldol reactions. [ABSTRACT FROM AUTHOR]

Drought stress adversely affects growth, development, productivity, and fiber quality of cotton (Gossypium hirsutum L). Breeding strategies to enhance drought tolerance require an improved knowledge of plant drought responses necessitating proper identification of drought-tolerant genotypes of crops, including cotton. The objective of this study was to classify the selected cotton genotypes for their drought tolerance ability based on morpho-physio-biochemical traits using Hierarchical Ward's cluster analysis. Five genotypes of cotton (Takfa 3, Takfa 6, Takfa 7, Takfa 84–4, and Takfa 86–5) were selected as plant materials, and were grown under well-watered (WW; 98 ± 2% field capacity) and water-deficit (WD; 50 ± 2% field capacity) conditions for 16 days during the flower initiation stage. Data on morpho-physio-biochemical parameters and gene expression levels for these parameters were collected, and subsequently genotypes were classified either as a drought tolerant or drought susceptible one. Upregulation of GhPRP (proline-rich protein), GhP5CS (Δ1-pyrroline-5-carboxylate synthetase), and GhP5CR (Δ1-pyrroline-5-carboxylate reductase) in relation to free proline enrichment was observed in Takfa 3 genotype under WD condition. An accumulation of free proline, total soluble sugar, and potassium in plants under WD conditions was detected, which played a key role as major osmolytes controlling cellular osmotic potential. Magnesium and calcium concentrations were also enriched in leaves under WD conditions, functioning as essential elements and regulating photosynthetic abilities. Leaf greenness, net photosynthetic rate, stomatal conductance, and transpiration rate were also declined under WD conditions, leading to growth retardation, especially aboveground traits of Takfa 6, Takfa 7, Takfa 84–4, and Takfa 86–5 genotypes. An increase in leaf temperature (1.1 − 4.0 °C) and crop water stress index (CWSI > 0.75) in relation to stomatal closure and reduced transpiration rate was recorded in cotton genotypes under WD conditions compared with WW conditions. Based on the increase of free proline, soluble sugar, leaf temperature, and CWSI, as well as the decrease of aboveground growth traits and physiological attributes, five genotypes were categorized into two cluster groups: drought tolerant (Takfa 3) and drought susceptible (Takfa 6, Takfa 7, Takfa 84–4, and Takfa 86–5). The identified drought-tolerant cotton genotype, namely, Takfa 3, may be grown in areas experiencing drought conditions. It is recommended to further validate the yield traits of Takfa 3 under rainfed field conditions in drought-prone environments. [ABSTRACT FROM AUTHOR]

The E3 ligase-degron interaction determines the specificity of the ubiquitin‒proteasome system. We recently discovered that FEM1B, a substrate receptor of Cullin 2-RING ligase (CRL2), recognizes C-degrons containing a C-terminal proline. By solving several cryo-EM structures of CRL2FEM1B bound to different C-degrons, we elucidate the dimeric assembly of the complex. Furthermore, we reveal distinct dimerization states of unmodified and neddylated CRL2FEM1B to uncover the NEDD8-mediated activation mechanism of CRL2FEM1B. Our research also indicates that, FEM1B utilizes a bipartite mechanism to recognize both the C-terminal proline and an upstream aromatic residue within the substrate. These structural findings, complemented by in vitro ubiquitination and in vivo cell-based assays, demonstrate that CRL2FEM1B-mediated polyubiquitination and subsequent protein turnover depend on both FEM1B-degron interactions and the dimerization state of the E3 ligase complex. Overall, this study deepens our molecular understanding of how Cullin-RING E3 ligase substrate selection mediates protein turnover. A key question in the ubiquitin-proteasome system is how E3 ligases select their substrates. Here, the authors reveal that CRL2FEM1B E3 ligase functions as a dimer and employs a bipartite mode of substrate recognition, requiring a C-terminal proline and an upstream aromatic residue in the target. [ABSTRACT FROM AUTHOR]

Proline is widely known as the only proteogenic amino acid with a secondary amine. In addition to its crucial role in protein structure, the secondary amino acid modulates neurotransmission and regulates the kinetics of signaling proteins. To understand the structural basis of proline import, we solved the structure of the proline transporter SIT1 in complex with the COVID-19 viral receptor ACE2 by cryo-electron microscopy. The structure of pipecolate-bound SIT1 reveals the specific sequence requirements for proline transport in the SLC6 family and how this protein excludes amino acids with extended side chains. By comparing apo and substrate-bound SIT1 states, we also identify the structural changes that link substrate release and opening of the cytoplasmic gate and provide an explanation for how a missense mutation in the transporter causes iminoglycinuria. The SIT1-ACE2 complex transports the amino acid proline and is the receptor of SARS-CoV-2. Here, the authors identify specific sequence requirements for proline transport and explain for how a missense mutation causes iminoglycinuria. [ABSTRACT FROM AUTHOR]

Understanding the intricate interactions governing protein and peptide behavior in liquid–liquid phase separation (LLPS) is crucial for unraveling biological functions and dysfunctions. This study employs a residue-leveled coarse-grained molecular dynamics approach to simulate the phase separation of repetitive polyproline and polyarginine peptides (poly PR) with varying lengths and sequences in solution, considering different concentrations and temperatures. Our findings highlight the crucial role of sequence order in promoting LLPS in peptides with identical lengths of repetitive sequences. Interestingly, repetitive peptides containing fewer than 10 polyarginine repeats exhibit no LLPS, even at salt concentrations up to 3 M. Notably, our simulations align with experimental observations, pinpointing a salt concentration of 2.7 M for PR25-induced LLPS. Utilizing the same methodology, we predict the required salt concentrations for LLPS induction as 1.2 M, 1.5 M, and 2.7 M for PR12, PR15, and PR35, respectively. These predictions demonstrate good agreement with experimental results. Extending our investigation to include the peptide glutamine and arginine (GR15) in DNA solution, our simulations mirror experimental observations of phase separation. To unveil the molecular forces steering peptide phase separation, we introduce a dielectric constant modifier and hydrophobicity disruptor into poly PR systems. Our coarse-grained analysis includes an examination of temperature effects, leading to the inference that both hydrophobic and electrostatic interactions drive phase separation in peptide systems. [ABSTRACT FROM AUTHOR]

The kinetic regularities of crystallization (its order and constants) in a model solution of human synovia (inorganic composition) under conditions close to physiological have been investigated. The crystallization constants in a pure solution and in the presence of organic synovia additives with variation in their concentration and supersaturation of the model solution are determined. The following descending order sequence is proposed for the influence of additives on the general and particular kinetic characteristics of crystallization in a model synovial solution: glucose → proline → alanine → glycine → citric acid. It is found that impurities affect to a greater extent the nucleation process rather than growth stages. [ABSTRACT FROM AUTHOR]

Potato is the fourth most important food crop. Recently, negative effects of a temperature drop on field crops have been increasingly frequently recorded. The elucidation of the mechanisms of plant tolerance to cold contributes to the development of measures to reduce crop yield losses from prolonged low temperatures. Potato health can be improved with the help of microclonal propagation. We studied short-term treatments of roots with indole-3-acetic acid (IAA) or melatonin (Mel) as a stimulus to activate the protective responses of potato regenerants to the later effects of hypothermia. The effect of 4-h treatment of roots with 0.1 μM IAA or Mel solutions on the cold tolerance of Solanum tuberosum L. regenerant plants in aquaculture was investigated. Two lines of regenerants obtained in vitro from the apical (AR) and middle part (MR) of the shoot of sterile plants of different growth intensity were used as a study object. It was found that hypothermia (4 °C, 3 days) most affected the actively growing plant organs: leaves and roots in MR, and leaves, stems, and stolons in AR. The most damaged AR leaves retained severe dehydration and elevated oxidative status during natural recovery, despite increased superoxide dismutase intensity and free proline levels. Pretreatment of plants with individual hormones increased their resistance to damaging hypothermia, manifested by changes in metabolic and growth responses. IAA pretreatment exerted a greater positive effect than Mel pretreatment. IAA treatment stimulated the root and leaf growth recovery in MR by reducing oxidative stress and restoring constitutive water levels at increased free proline, ascorbic acid, and the sum of flavonoids and phenolic compounds. Possible reasons for the differences between AR and MR hormone restoration therapy are discussed. [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]