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Salicylic acid (SA) is an important signaling molecule involved in plant defense. While many proteins play essential roles in SA signaling, increasing evidence shows that responses to SA appear to involve and require lipid signals. The phospholipid-generated signal transduction involves a family of enzymes that catalyze the hydrolysis or phosphorylation of phospholipids in membranes to generate signaling molecules, which are important in the plant cellular response. In this review, we focus first, the role of SA as a mitigator in biotic/abiotic stress. Later, we describe the experimental evidence supporting the phospholipid-SA connection in plant cells, emphasizing the roles of the secondary lipid messengers (phosphatidylinositol 4,5-bisphosphate (PIP 2 ) and phosphatidic acid (PA)) and related enzymes (phospholipase D (PLD) and phospholipase C (PLC)). By placing these recent finding in context of phospholipids and SA in plant cells, we highlight the role of phospholipids as modulators in the early steps of SA triggered transduction in plant cells.

Salicylic acid (SA) is a crucial signal molecule and phytohormone, regulating the biotic and abiotic stress responses as well as plant development. In this research, we comparatively examined the effects of exogenous SA on the behaviors of thiamethoxam (THIM), hymexazol (HMI) and chlorantraniliprole (CAP) in cucumber planting systems under soil pot and hydroponic cultivation. The cucumber seedlings were transplanted into soil or nutrient solution containing a target pesticide (1 mg/kg) or a target pesticide with SA (1 mg/kg) after the fourth leaf emerged. We examined the behaviors of pesticides both the SA treated and nontreated plants by analyzing cucumber root, stem and leaf samples taken on the 0-21 days following the root treatment. The root concentration factor (RCF), bioconcentration factor (BCF) and translocation factors (TF stem and TF leaf ) were calculated for the comparison of the differences in the behaviors of pesticides. We found that the accumulation behaviors of pesticides in planting systems were related to the physicochemical properties of pesticides, exogenous SA and cultivation methods. Exogenous SA had a certain promoting effect on the degradation of pesticides in soil and nutrient solution, resulting in reduced half-lives. SA was able to block the accumulation of pesticides in roots and leaves and alleviated the accumulation ability of roots, the bioconcentration ability of plants, and the translocation ability from roots to leaves. Interestingly, SA had more distinct effects on the behaviors of pesticides under hydroponic experiments than under soil pot experiments. Furthermore, the behaviors of clothianidin (CLO), the main metabolite of THIM, were also assessed, indicating that THIM was mainly metabolized to CLO in leaves and stems, and SA facilitated this process. Our findings suggest that SA has a certain regulatory effect on the accumulation of pesticides in plants, and SA-blocked pesticide accumulation is practically rewarding for improving food safety., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled, “Exogenous salicylic acid blocks the accumulation of pesticides in cucumber planting systems under soil pot and hydroponic cultivation modes”., (Copyright © 2020 Elsevier Inc. All rights reserved.)

To control food contamination and meet the growing demand for high quality food, a novel and excellent starch composite film as packing material with optimized physical, mechanical properties and antimicrobial activity was produced in this paper. Starch-based composite films incorporated with salicylic acid (SA) and waxy maize starch nanoparticles/κ-carrageenan (WMSNs/KC) were used to achieve antimicrobial activity and improve the mechanical properties. WMSNs were fabricated through enzymolysis and recrystallisation method, followed by individually adding KC to form WMSNs/KC by self-assembly, and used as a nanofiller and stabilizer to be incorporated into hydroxypropyl tapioca starch-based films at a concentration of 0-9%. Characterization of macromorphology and scanning electron microscope indicated the starch composite films with WMSNs/KC were smooth, uniform, and transparent. X-ray diffraction pattern and Thermogravimetric analysis also showed strong interactions such as hydrogen bond formation among films, WMSNs/KC and SA. Compared with the pure starch-based films, the composite films reinforced by the addition of WMSNs/KC significantly increased the tensile strength, water vapor barrier and thermal stability, while the transparency and elongation at break decreased slightly. Moreover, the starch composite films showed excellent antimicrobial activity for three typical undesired microorganisms in foods, Escherichia coli, Staphylococcus aureus, and Bacillus subtilis., Competing Interests: Declaration of competing interest The authors have read the policy on conflicts of interest and declare no competing interests with other people or organization., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Salicylic acid (SA) and gibberellins (GAs), as two important plant growth hormones, play a key role in increasing plant tolerance to abiotic stress. They contribute to the increased plant antioxidant activities in ROS scavenging, which is related to the enzymes involved in H 2 O 2 -detoxifying. In photosynthetic cycles, the endogenous form of these phytohormones enhances photosynthetic properties such as stomatal conductance, net photosynthesis (PN), photosynthetic oxygen evolution, and efficiency of carboxylation. Furthermore, in cell cycle, they are able to influence division and expansion of cell growth in plants under stress, leading to increased growth of radicle cells in a meristem, and ultimately contributing to the increased germination rate and lengths of shoot and root in the stress-affected plants. In the case of crosstalk between SA and GA, exogenous GA 3 can upregulate biosynthesis of SA and consequently result in rising levels of SA, enhancing plant defense response to environmental abiotic stresses. The aim of this paper was to investigate the mechanisms related to GA and SA phytohormones in amelioration of abiotic stress, in particular, heavy metal stress.

Tomato Atypical Receptor Kinase 1 (TARK1) is a pseudokinase required for postinvasion immunity. TARK1 was originally identified as a target of the Xanthomonas euvesicatoria effector protein Xanthomonas outer protein N (XopN), a suppressor of early defense signaling. How TARK1 participates in immune signal transduction is not well understood. To gain insight into TARK1's role in tomato ( Solanum lycopersicum ) immunity, we used a proteomics approach to isolate and identify TARK1-associated immune complexes formed during infection. We found that TARK1 interacts with proteins predicted to be associated with stomatal movement. TARK1 CRISPR mutants and overexpression (OE) lines did not display differences in light-induced stomatal opening or abscisic acid-induced stomatal closure; however, they did show altered stomatal movement responses to bacteria and biotic elicitors. Notably, we found that TARK1 CRISPR plants were resistant to Pseudomonas syringae pathovar tomato strain DC3000-induced stomatal reopening, and TARK1 OE plants were insensitive to P syringae pathovar tomato strain DC3118 (coronatine deficit)-induced stomatal closure. We also found that TARK1 OE in leaves resulted in increased susceptibility to bacterial invasion. Collectively, our results indicate that TARK1 functions in stomatal movement only in response to biotic elicitors and support a model in which TARK1 regulates stomatal opening postelicitation., (© 2020 American Society of Plant Biologists. All Rights Reserved.)

The plant stress hormone salicylic acid (SA) participates in local and systemic acquired resistance, which eventually leads to whole-plant resistance to bacterial pathogens. However, if SA-mediated signaling is not appropriately controlled, plants incur defense-associated fitness costs such as growth inhibition and cell death. Despite its importance, to date only a few components counteracting the SA-primed stress responses have been identified in Arabidopsis ( Arabidopsis thaliana ). These include other plant hormones such as jasmonic acid and abscisic acid, and proteins such as LESION SIMULATING DISEASE1, a transcription coregulator. Here, we describe PLANT NATRIURETIC PEPTIDE A (PNP-A), a functional analog to vertebrate atrial natriuretic peptides, that appears to antagonize the SA-mediated plant stress responses. While loss of PNP-A potentiates SA-mediated signaling, exogenous application of synthetic PNP-A or overexpression of PNP-A significantly compromises the SA-primed immune responses. Moreover, we identify a plasma membrane-localized receptor-like protein, PNP-R2, that interacts with PNP-A and is required to initiate the PNP-A-mediated intracellular signaling. In summary, our work identifies a peptide and its putative cognate receptor as counteracting both SA-mediated signaling and SA-primed cell death in Arabidopsis., (© 2020 American Society of Plant Biologists. All rights reserved.)

Although it is well known that parasitic weeds such as Orobanche (broomrape) significantly reduce the yield of economically important crops, their infection-induced oxidative changes need more exploration in their host plants. Moreover, applying an eco-friendly approach to minimize the infection is not yet available. This study was conducted to understand the effect of Orobanche ramosa infection on oxidative and redox status of tomato plants and the impact of hormonal (indole acetic acid (IAA); 0.09 mM and salicylic acid (SA); 1.0 mM) seed-priming upon mitigating the infection threats. Although Orobanche invades tomato roots, its inhibitory effects on shoot biomass were also indicted. Orobanche infection usually induces oxidative damage i.e., high lipid peroxidation, lipoxygenase activity and H 2 O 2 levels, particularly for roots. Interestingly, hormonal seed-priming significantly enhanced tomato shoots and roots growth under both healthy and infected conditions. Also, IAA and SA treatment significantly reduced Orobanche infection-induced oxidative damage. The protective effect of seed-priming was explained by increasing the antioxidant defense markers including the antioxidant metabolites (i.e., total antioxidant capacity, carotenoids, phenolics, flavonoids, ASC, GSH, tocopherols) and enzymes (CAT, POX, GPX, SOD, GR, APX, MDHAR, DHAR), particularly in infected tomato seedlings. Additionally, cluster analysis indicated the differential impact of IAA- and SA-seed-priming, whereas lower oxidative damage and higher antioxidant enzymes' activities in tomato root were particularly reported for IAA treatment. The principal component analysis (PCA) also proclaimed an organ specificity depending on their response to Orobanche infection. Collectively, here and for the first time, we shed the light on the potential of seed-priming with either IAA or SA to mitigate the adverse effect of O. ramosa stress in tomato plants, especially at oxidative stress levels., Competing Interests: Declaration of Competing Interest The authors have declared no conflict of interest., (Copyright © 2020 Elsevier GmbH. All rights reserved.)

Capparis spinosa is an edible medicinal plant which is considered as an excellent source of rutin. Rutin is a glycoside of the flavonoid quercetin that has been reported to have a beneficial role in controlling various diseases such as hypertension, arteriosclerosis, diabetes, and obesity. In this study, the partial cDNA of four genes involved in the rutin biosynthetic pathway including 4-coumaroyl CoA ligase (4CL), flavonoid 3'-hydroxylase (F3'H), flavonol synthase (FLS) and flavonol-3-O-glucoside L-rhamnosyltransferase (RT) were identified in C.spinosa plants for the first time. The protein sequences of these genes shared high similarity with the same proteins in other plant species. Subsequently, the expression patterns of these genes as well as rutin accumulation in C.spinosa leaves treated with different concentrations of salicylic acid (SA) and methyl jasmonate (MeJA) and also in different tissues of Caper plants treated with 100 mgL -1 SA and 150 μM MeJA were evaluated. The expression of all four genes was clearly up-regulated and rutin contents increased in response to MeJA and SA treatments after 24 h. The highest rutin contents (5.30 mgg -1 DW and 13.27 mgg -1 DW), as well as the highest expression levels of all four genes, were obtained using 100 mgL -1 SA and 150 μM MeJA, respectively. Among the different tissues, the highest rutin content was observed in young leaves treated with 150 μM MeJA, which corresponded to the expression of related genes, especially RT, as a key gene in the rutin biosynthetic pathway. These results suggest that rutin content in various tissues of C. spinosa can be enhanced to a significant extent by MeJA and SA treatments and the gene expression patterns of rutin-biosynthesis-related genes are regulated by these elicitors.

An aliphatic ester of hydroxysalicylic acid ( 6 ), reported for the first time from a natural source in addition to five known compounds were isolated from the fermented Carica papaya L. preparation, a commercialized functional food. The known compounds were identified as 5-hydroxymethylfurfuraldehyde ( 1 ), trans -caffeic acid ( 2 ), butyl 4-hydroxybenzoate (butylparaben) ( 3 ), lycopene ( 4 ), benzyl isothiocyanate ( 5 ). Compounds 1 and 3 were reported for the first time from Papaya fruits through this study. The new compound showed a moderate antioxidant activity and a potent hair growth stimulating activity in vitro .

Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) biotype B is a key pest of Solanum lycopersicum L. (Solanaceae) throughout the world. In this study, we examined the induction of resistance on tomato plants treated with SA, BABA, and Trichoderma either individually or in combination against B. tabaci biotype B through the assessment of some biological and behavioral aspects of this insect pest. Also, to understand the mode of action of these inducers, we correlated and analyzed the biochemical basis of plant resistance, by measuring levels of polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia lyase (PAL), and phenolic content in leaves of treated tomato plants. The longest development time of whitefly immature stages was recorded for plants treated with root β-aminobutyric acid application (RBABA) + root Trichoderma application (RT), root salicylic acid application (RSA) + RT, and RT. In a free-choice assay, B. tabaci adults showed a significantly lower preference for settling and oviposition in RBABA + RT, RSA + RT, and RT in comparison with control. In a no-choice assay, B. tabaci females laid significantly fewer eggs on treatments than those in control, with better results observed in RBABA + RT. Plants responded to different treatments and showed higher induction of PPO, POD, and PAL activities, besides the higher accumulation of phenols in RBABA + RT, RSA + RT, and RT treatments. These results suggest that RBABA + RT, RSA + RT, and RT could be utilized for the induction of effective plant defense against B. tabaci.

Background: In this study, response surface methodology (RSM) and artificial neural network (ANN) was used to construct the predicted models of linear, quadratic and interactive effects of two independent variables viz. salicylic acid (SA) and chitosan (CS) for the production of amarogentin (I), swertiamarin (II) and mangiferin (III) from shoot cultures of Swertia paniculata Wall. These compounds are the major therapeutic metabolites in the Swertia plant, which have significant role and demand in the pharmaceutical industries., Results: Present study highlighted that different concentrations of SA and CS elicitors substantially influenced the % yield of (I), (II) and (III) compounds in the shoot culture established on modified ½ MS medium (supplemented with 2.22 mM each of BA and KN and 2.54 mM NAA). In RSM, different response variables with linear, quadratic and 2 way interaction model were computed with five-factor-three level full factorial CCD. In ANN modelling, 13 runs of CCD matrix was divided into 3 subsets, with approximate 8:1:1 ratios to train, validate and test. The optimal enhancement of (I) (0.435%), (II) (4.987%) and (III) (4.357%) production was achieved in 14 days treatment in shoot cultures of S. paniculata elicited by 9 mM and 12 mg L - 1 concentrations (SA) and (CS)., Conclusions: In optimization study, (I) show 0.170-0.435%; (II) display 1.020-4.987% and (III) upto 2.550-4.357% disparity with varied range of SA (1-20 mM) and CS (1-20 mg L - 1 ). Overall, optimization of elicitors to promote secoiridoid and xanthone glycoside production with ANN modeling (r 2  = 100%) offered more significant results as compared to RSM (r 2  = 99.8%).

The discovery of specific microbiota metabolite mechanisms has begun to motivate new therapeutic approaches. Inspired by our mechanistic studies of microbiota-derived short chain fatty acid (SCFA) acylation of bacterial virulence factors, here we explored covalent protein acylation therapeutics as potential anti-infectives. For these studies, we focused on acetyl-salicylic acid, aspirin, and discovered that SCFA analogues such as butyryl-salicylic acid showed significantly improved anti-infective activity against Salmonella Typhimurium. Structure-activity studies showed that the ester functionality of butyryl-salicylic acid was crucial and associated with the acylation of key bacterial virulence factors and metabolic enzymes, which are important for Salmonella infection of host cells and bacterial growth. Beyond the Gram-negative bacterial pathogens, butyryl-salicylic acid also showed better antibacterial activity compared to aspirin against Clostridioides difficile , a clinically challenging Gram-positive bacterial pathogen. Notably, coadministration of butyryl-salicylic acid, but not aspirin, effectively attenuated Salmonella pathogenesis in vivo . This study highlights how the analysis of microbiota metabolite mechanisms may inspire the repurposing and development of new anti-infective agents.

Mitogen-activated protein kinase (MAPK) is a form of serine/threonine protein kinase that activated by extracellular stimulation acting through the MAPK cascade (MAPKKK-MAPKK-MAPK). The MAPK cascade gene family, an important family of protein kinases, plays a vital role in responding to various stresses and hormone signal transduction processes in plants. In this study, we identified 14 CmMAPKs, 6 CmMAPKKs and 64 CmMAPKKKs in melon genome. Based on structural characteristics and a comparison of phylogenetic relationships of MAPK gene families from Arabidopsis, cucumber and watermelon, CmMAPKs and CmMAPKKs were categorized into 4 groups, and CmMAPKKKs were categorized into 3 groups. Furthermore, chromosome location revealed an unevenly distribution on chromosomes of MAPK cascade genes in melon, respectively. Eventually, qRT-PCR analysis showed that all 14 CmMAPKs had different expression patterns under drought, salt, salicylic acid (SA), methyl jasmonate (MeJA), red light (RL), and Podosphaera xanthii (P. xanthii) treatments. Overall, the expression levels of CmMAPK3 and CmMAPK7 under different treatments were higher than those in control. Our study provides an important basis for future functional verification of MAPK genes in regulating responses to stress and signal substance in melon., Competing Interests: The authors have declared that no competing interests exist.

Susceptibility of plants to abiotic stresses, including extreme temperatures, salinity and drought, poses an increasing threat to crop productivity worldwide. Here the drought-induced response of maize was modulated by applications of methyl jasmonate (MeJA) and salicylic acid (SA) to seeds prior to sowing and to leaves prior to stress treatment. Pot experiments were conducted to ascertain the effects of exogenous applications of these hormones on maize growth, physiology and biochemistry under drought stress and well-watered (control) conditions. Maize plants were subjected to single as well as combined pre-treatments of MeJA and SA. Drought stress severely affected maize morphology and reduced relative water content, above and below-ground biomass, rates of photosynthesis, and protein content. The prolonged water deficit also led to increased relative membrane permeability and oxidative stress induced by the production of malondialdehyde (from lipid peroxidation), lipoxygenase activity (LOX) and the production of H2O2. The single applications of MeJA and SA were not found to be effective in maize for drought tolerance while the combined pre-treatments with exogenous MeJA+SA mitigated the adverse effects of drought-induced oxidative stress, as reflected in lower levels of lipid peroxidation, LOX activity and H2O2. The same pre-treatment also maintained adequate water status of the plants under drought stress by increasing osmolytes including proline, total carbohydrate content and total soluble sugars. Furthermore, exogenous applications of MeJA+SA approximately doubled the activities of the antioxidant enzymes catalase, peroxidase and superoxide dismutase. Pre-treatment with MeJA alone gave the highest increase in drought-induced production of endogenous abscisic acid (ABA). Pre-treatment with MeJA+SA partially prevented drought-induced oxidative stress by modulating levels of osmolytes and endogenous ABA, as well as the activities of antioxidant enzymes. Taken together, the results show that seed and foliar pre-treatments with exogenous MeJA and/or SA can have positive effects on the responses of maize seedlings to drought., Competing Interests: The authors have declared that no competing interests exist.

Chitosan (CHT) induces stomatal closure and thus plays a crucial role in plants to adapt to the adverse environments. Our previous results of a SA-deficient mutant nahG suggest that endogenous salicylic acid (SA) is involved in the CHT signaling in guard cells. Here in order to make the involvement definite, we examined stomatal responses to CHT of another SA-deficient mutant, sid2 , and an SA receptor mutant, npr1-3 . The sid2 mutation impaired CHT-induced stomatal closure and reactive oxygen species production and both impairments were complemented with exogenous SA application. Moreover, the CHT-induced stomatal closure is disrupted in the npr1-3 mutant. These results suggest that endogenous SA is involved in the CHT-induced stomatal closure via the SA receptor, NPR1. Abbreviations : SA: salicylic acid; ABA: abscisic acid; ROS: reactive oxygen species; NPR1: nonexpresser of pathogenesis-related genes1; CHT: chitosan; DAB: 3,3'-diaminobenzidine.

Leaf senescence is tightly regulated by numerous internal cues and external environmental signals. The process of leaf senescence is promoted by a low ratio of red to far-red (R:FR) light, FR light, or extended darkness and is repressed by a high ratio of R:FR light or R light. However, the precise regulatory mechanisms by which plants assess external light signals and their internal cues to initiate and control the process of leaf senescence remain largely unknown. In this study, we discovered that the light-signaling protein FAR-RED ELONGATED HYPOCOTYL3 (FHY3) negatively regulates age-induced and light-mediated leaf senescence in Arabidopsis ( Arabidopsis thaliana ). FHY3 directly binds to the promoter region of transcription factor gene WRKY28 to repress its expression, thus negatively regulating salicylic acid biosynthesis and senescence. Both the fhy3 loss-of-function mutant and WRKY28 -overexpressing Arabidopsis plants exhibited early senescence under high R:FR light conditions, indicating that the FHY3- WRKY28 transcriptional module specifically prevents leaf senescence under high R:FR light conditions. This study reveals the physiological and molecular functions of FHY3 and WRKY28 in leaf senescence and provides insight into the regulatory mechanism by which plants integrate dynamic environmental light signals and internal cues to initiate and control leaf senescence., (© 2020 American Society of Plant Biologists. All rights reserved.)

Key Message: SBTX has defensive role against C. kikuchii, and therefore, its constituent genes SBTX17 and SBTX27 are promising candidates to engineer pathogen resistant plants. Soybean (Glycine max [L.] Merr.) is economically the most important legume crop in the world. Its productivity is strongly affected by fungal diseases, which reduce soybean production and seed quality and cause losses of billions of dollars worldwide. SBTX is a protein that apparently takes part in the defensive chemical arsenal of soybean against pathogens. This current study provides data that reinforce this hypothesis. Indeed, SBTX inhibited in vitro the mycelial growth of Cercospora kikuchii, it is constitutively located in the epidermal region of the soybean seed cotyledons, and it is exuded from mature imbibed seeds. Moreover, RT-qPCR analysis of the SBTX associated genes, SBTX17 and SBTX27, which encode for the 17 and 27 kDa polypeptide chains, showed that both genes are expressed in all studied plant tissues during the soybean development, with the highest levels found in the mature seeds and unifoliate leaves. In addition, to assess a local response of the soybean secondary leaves from 35-day-old plants, they were inoculated with C. kikuchii and treated with salicylic acid. It was verified using RT-qPCR that SBTX17 and SBTX27 genes overexpressed in leaves compared to controls. These findings strongly suggest that SBTX has defensive roles against C. kikuchii. Therefore, SBTX17 and SBTX27 genes are promising candidates to engineer pathogen resistant plants.

N-terminal (Nt) acetylation (NTA) is an ample and irreversible cotranslational protein modification catalyzed by ribosome-associated Nt-acetyltransferases. NTA on specific proteins can act as a degradation signal (called an Ac/N-degron) for proteolysis in yeast and mammals. However, in plants, the biological relevance of NTA remains largely unexplored. In this study, we reveal that Arabidopsis ( Arabidopsis thaliana ) SIGMA FACTOR-BINDING PROTEIN1 (SIB1), a transcription coregulator and a positive regulator of salicylic acid-primed cell death, undergoes an absolute NTA on the initiator Met; Nt-acetyltransferase B (NatB) partly contributes to this modification. While NTA results in destabilization of certain target proteins, our genetic and biochemical analyses revealed that plant NatB-involved NTA instead renders SIB1 more stable. Given that the ubiquitin/proteasome system stimulates SIB1 degradation, it seems that the NTA-conferred stability ensures the timely expression of SIB1-dependent genes, mostly related to immune responses. Taking our findings together, here we report a noncanonical NTA-driven protein stabilization in land plants., (© 2020 The authors. All Rights Reserved.)

Implications of the role of antioxidant buffering in reactive oxygen species (ROS)-antioxidant interactions and associated redox regulation during adventitious root formation (ARF) were assessed in redox-manipulated salicylic acid (SA)-treated hypocotyl explants of mung bean [Vigna radiata (L.) R. Wilczek]. Application of pro-oxidant H 2 O 2 (500 μM) followed by SA (600 μM) was shown to stimulate ARF, whereas treatments combining 600 μM SA and 10 × 10 -4 M DPI (diphenyleneiodonium, an inhibitor of NADPH-oxidase) and 600 μM and SA 10 × 10 -4 M (dimethylthiourea, a free radical scavenger) were found to prevent ARF. The redox status of the experimental explants monitored under such treatment conditions (in terms of accumulation of pro-oxidants, in situ localization of O 2 - and H 2 O 2 , radical scavenging property and total thiol content) revealed significant changes in ROS-antioxidant interactions at the metabolic interface, causing alterations in the pattern of ARF. Further, the assessment of activities and transcript abundance of the enzymes of the H 2 O 2 turnover pathway (mainly the ascorbate-glutathione system) supported the transcriptional regulation of genes such as vrrboh, vrAPX, vrGR, vrSOD, and vrCAT and the activities of the relevant enzymes necessary for the generation of endogenous redox cues during ARF. The present work provides an inventory in support of the importance of antioxidant buffering associated with redox regulation for the origin of the metabolic redox cue (redox signal) necessary for SA-induced ARF in mung bean., Competing Interests: Declaration of Competing Interest The authors declare that they has no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier GmbH. All rights reserved.)

Background: Canker disease caused by Neoscytalidium dimidiatum is a devastating disease resulting in a major loss to the pitaya industry. However, resistance proteins in plants play crucial roles to against pathogen infection. Among resistance proteins, the leucine-rich repeat (LRR) protein is a major family that plays crucial roles in plant growth, development, and biotic and abiotic stress responses, especially in disease defense., Results: In the present study, a transcriptomics analysis identified a total of 272 LRR genes, 233 of which had coding sequences (CDSs), in the plant pitaya (Hylocereus polyrhizus) in response to fungal Neoscytalidium dimidiatum infection. These genes were divided into various subgroups based on specific domains and phylogenetic analysis. Molecular characterization, functional annotation of proteins, and an expression analysis of the LRR genes were conducted. Additionally, four LRR genes (CL445.Contig4_All, Unigene28_All, CL28.Contig2_All, and Unigene2712_All, which were selected because they had the four longest CDSs were further assessed using quantitative reverse transcription PCR (qRT-PCR) at different fungal infection stages in different pitaya species (Hylocereus polyrhizus and Hylocereus undatus), in different pitaya tissues, and after treatment with salicylic acid (SA), methyl jasmonate (MeJA), and abscisic acid (ABA) hormones. The associated protein functions and roles in signaling pathways were identified., Conclusions: This study provides a comprehensive overview of the HpLRR family genes at transcriptional level in pitaya in response to N. dimidiatum infection, it will be helpful to understand the molecular mechanism of pitaya canker disease, and lay a strong foundation for further research.

Due to the long growth period of plants, phytoremediation is time costly. Improving the accumulation of cadmium (Cd) in shoots of plants will promote the efficiency of phytoremediation. In this study, two senescence-relative phytohormones, abscisic acid (ABA) and salicylic acid (SA), were applied to strengthening phytoremediation of Cd by tall fescue (Festuca arundinacea S.). Under hydroponic culture, phytohormones treatment increased the Cd content of shoots 11.4-fold over the control, reaching 316.3 mg/kg (dry weight). Phytohormones-induced senescence contributes to the transport of heavy metals, and HMA3 was found to play a key role in this process. Additionally, this strategy could strengthen the accumulation of Cu and Zn in tall fescue shoots. Moreover, in soil pot culture, the strategy increased shoot Cd contents 2.56-fold over the control in tall fescue, and 2.55-fold over the control in Indian mustard (Brassica juncea L.), indicating its comprehensive adaptability and potential use in the field. In summary, senescence-induced heavy metal transport is developed as a novel strategy to strengthen phytoremediation. The strategy could be applied at the end of phytoremediation with an additional short duration (7 days) with comprehensive adaptability, and markedly strengthen the phytoremediation in the field., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Demand for agricultural crop continues to escalate in response to increasing population and damage of prime cropland for cultivation. Research interest is diverted to utilize soils with marginal plant production. Moisture stress has negative impact on crop growth and productivity. The plant growth promoting rhizobacteria (PGPR) and plant growth regulators (PGR) are vital for plant developmental process under moisture stress. The current study was carried out to investigate the effect of PGPR and PGRs (Salicylic acid and Putrescine) on the physiological activities of chickpea grown in sandy soil. The bacterial isolates were characterized based on biochemical characters including Gram-staining, P-solubilisation, antibacterial and antifungal activities and catalases and oxidases activities and were also screened for the production of indole-3-acetic acid (IAA), hydrogen cyanide (HCN) and ammonia (NH3). The bacterial strains were identified as Bacillus subtilis, Bacillus thuringiensis and Bacillus megaterium based on the results of 16S-rRNA gene sequencing. Chickpea seeds of two varieties (Punjab Noor-2009 and 93127) differing in sensitivity to drought were soaked for 3 h before sowing in fresh grown cultures of isolates. Both the PGRs were applied (150 mg/L), as foliar spray on 20 days old seedlings of chickpea. Moisture stress significantly reduced the physiological parameters but the inoculation of PGPR and PGR treatment effectively ameliorated the adverse effects of moisture stress. The result showed that chickpea plants treated with PGPR and PGR significantly enhanced the chlorophyll, protein and sugar contents. Shoot and root fresh (81%) and dry weights (77%) were also enhanced significantly in the treated plants. Leaf proline content, lipid peroxidation and antioxidant enzymes (CAT, APOX, POD and SOD) were increased in reaction to drought stress but decreased due to PGPR. The plant height (61%), grain weight (41%), number of nodules (78%) and pod (88%), plant yield (76%), pod weight (53%) and total biomass (54%) were higher in PGPR and PGR treated chickpea plants grown in sandy soil. It is concluded from the present study that the integrative use of PGPR and PGRs is a promising method and eco-friendly strategy for increasing drought tolerance in crop plants., Competing Interests: The authors have declared that no competing interests exist.

Chemical stimulants, used to enhance biomass yield, are highly desirable for the commercialisation of algal products for a wide range of applications in the food, pharma and biofuels sectors. In the present study, phenolic compounds, varying in substituents and positional isomers on the arene ring have been evaluated to determine structure-activity relationship and growth. The phenols, catechol, 4-methylcatechol and 2, 4-dimethyl phenol were generally inhibitory to growth as were the compounds containing an aldehyde function. By contrast, the phenolic acids, salicylic acid, aspirin and 4-hydroxybenzoate markedly stimulated cell proliferation enhancing cell numbers by 20-45% at mid-log phase. The order of growth stimulation was ortho > para > meta with respect to the position of the OH group. Both SA and aspirin reduced 16:3 in chloroplast galactolipids. In addition, both compounds inhibited lipoxygenase activity and lowered the levels of lipid hydroperoxides and malondialdehydes in the cells. The present study has demonstrated the possibility of using SA or aspirin to promote algal growth through the manipulation of lipid metabolising enzymes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Isochorismate synthase (ICS) plays an essential role in the accumulation of salicylic acid (SA) and plant disease resistance. Diseases caused by Botryosphaeria dothidea affect apple yields. Thus, it is important to understand the role of ICS1 in disease resistance to B. dothidea in apple. In this study, SA treatment enhanced the resistance to B. dothidea. MdICS1 was induced by B. dothidea and enhanced the resistance to B. dothidea. MdICS1 promoter analysis indicated that the W-box was vital for the response to B. dothidea treatment. MdWRKY15 was found to interact with the W-box using yeast one-hybrid screening. Subsequently, the interaction was confirmed by EMSA, yeast one-hybrid, ChIP-PCR, and quantitative PCR assays. Moreover, luciferase and GUS analysis further indicated that MdICS1 was transcriptionally activated by MdWRKY15. Finally, we found the function of MdWRKY15 in the resistance to B. dothidea was partially dependent on MdICS1 from the phenotype of transgenic apples and calli. In summary, we revealed that MdWRKY15 activated the transcription of MdICS1 by directly binding to its promoter to increase the accumulation of SA and the expression of disease-related genes, thereby resulting in the enhanced resistance to B. dothidea in the SA biosynthesis pathway., (© 2019 Institute of Botany, Chinese Academy of Sciences.)

Background: Cruciferous foods rich in health-promoting metabolites are of particular interest to consumers as well as being a good source of bioactives-enriched ingredients. Several elicitors have been used to stimulate the biosynthesis and accumulation of secondary metabolites in foods; however, little is known about the response of new hybrid varieties, such as Bimi®, under field-crop production conditions. Therefore, this study was designed to evaluate the effect of salicylic acid (200 μmol L -1 , SA), methyl jasmonate (100 μmol L -1 , MeJA), and their combination on Bimi plant organs (inflorescences and aerial vegetative tissues - stems and leaves). For this, the composition of the glucosinolates present in the tissues was evaluated. Also, aqueous extracts of the plant material, obtained with different times of extraction with boiling water, were studied., Results: The results indicate that the combined treatment (SA + MeJA) significantly increased the content of glucosinolates in the inflorescences and that MeJA was the most effective elicitor in leaves. Regarding the aqueous extracts, the greatest amount of glucosinolates was extracted at 30 min - except for the leaves elicited with MeJA, for which 15 min was optimal., Conclusion: The elicitation in the field enriched leaves in glucobrassicin (GB), 4-methoxyglucobrassicin (MGB), and neoglucobrassicin (NGB) and stems and inflorescences in glucoraphanin, 4-hydroxyglucobrassicin, GB, MGB, and NGB. In this way, this enhanced vegetable material favored the presence of bioactives in the extracts, which is of great interest regarding enriched foods and ingredients with added value obtained from them. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

Biohybrid materials were prepared by co-assembling the three following components: nanotubular halloysite, microfibrous sepiolite, and cellulose nanofibers dispersed in water, in order to exploit the most salient features of each individual component and to render homogeneous, flexible, yet strong films. Indeed, the incorporation of halloysite improves the mechanical performance of the resulting hybrid nanopapers and the assembly of the three components modifies the surface features concerning wetting properties compared to pristine materials, so that the main characteristics of the resulting materials become tunable with regard to certain properties. Owing to their hierarchical porosity together with their diverse surface characteristics, these hybrids can be used in diverse biomedical/pharmaceutical applications. Herein, for instance, loading with two model drugs, salicylic acid and ibuprofen, allows controlled and sustained release as deduced from antimicrobial assays, opening a versatile path for developing other related organic-inorganic materials of potential interest in diverse application fields.

Heat stress is found to be a detrimental factor for growth and development of alfalfa (Medicago sativa L.) which is tremendously invaluable forage due to its high feed value and yield potential. Salicylic acid (SA) has been reported to play a pivotal role in the regulation of plants biotic and abiotic stress response. However, the role of exogenous SA in protecting alfalfa from heat-induced damage has rarely been studied. In this study, four-week-old alfalfa seedlings were treated with 0.25 mM or 0.5 mM SA five days prior to high stress treatment (three day), and various growth and physiological traits were measured. The results showed that exogenous SA pretreatment could improve leaf morphology, plant height, biomass, chlorophyll content, and photosynthetic efficiency of alfalfa under heat stress. Meanwhile, SA could alleviate heat-induced membrane damage by reducing electrolyte leakage (EL) and malondialdehyde (MDA) content, and regulate the activities of antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD). The results revealed that exogenous SA application enhanced alfalfa heat tolerance by modulating various morphological and physiological characteristics under heat stress, with more prominent effect at lower concentration (0.25 mM). Overall, this study provides fundamental insights into the SA-mediated physiological adaptation of alfalfa plants to heat stress, which could have useful implication in managing other plants which are suffering global warming., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Macarpine is a minor benzophenanthridine alkaloid with interesting biological activities, which is produced in only a few species of the Papaveraceae family, including Eschscholzia californica . Our present study was focused on the enhancement of macarpine production in E. californica suspension cultures using three elicitation models: salicylic acid (SA) (4; 6; 8 mg/L) elicitation, and simultaneous or sequential combinations of SA and L-tyrosine (1 mmol/L). Sanguinarine production was assessed along with macarpine formation in elicited suspension cultures. Alkaloid production was evaluated after 24, 48 and 72 h of elicitation. Among the tested elicitation models, the SA (4 mg/L), supported by L-tyrosine, stimulated sanguinarine and macarpine production the most efficiently. While sequential treatment led to a peak accumulation of sanguinarine at 24 h and macarpine at 48 h, simultaneous treatment resulted in maximum sanguinarine accumulation at 48 h and macarpine at 72 h. The effect of SA elicitation and precursor supplementation was evaluated also based on the gene expression of 4'-OMT, CYP719A2, and CYP719A3. The gene expression of investigated enzymes was increased at all used elicitation models and their changes correlated with sanguinarine but not macarpine accumulation.

The mechanism by which endogenous salicylic acid (SA) regulates leaf senescence remains elusive. Here we provide direct evidence that an enhancement of endogenous SA level, via chemical-induced upregulation of ISOCHORISMATE SYNTHASE 1 (ICS1), could significantly accelerate the senescence process of old leaves through mediation of the key SA signaling component NON EXPRESSOR OF PATHOGENESIS RELATED GENES 1 (NPR1) in Arabidopsis. Importantly, by taking advantage of this chemically induced leaf senescence system, we identified a mitogen-activated protein kinase (MAPK) cascade MKK4/5-MPK1/2 that is required for the SA/NPR1-mediated leaf senescence. Both MKK4/5 and MPK1/2 exhibited SA-induced kinase activities, with MPK1/2 being the immediate targets of MKK4/5. Double mutants of mkk4 mkk5 and mpk1 mpk2 displayed delayed leaf senescence, while constitutive overexpression of the kinase genes led to premature leaf senescence. Such premature leaf senescence was suppressed when they were overexpressed in an SA synthesis defective mutant (sid2) or signaling detective mutant (npr1). We further showed that MPK1, but not MPK2, could directly phosphorylate NPR1. Meanwhile, MPK1 also mediated NPR1 monomerization. Notably, induction of disease resistance was significantly compromised in the single and double mutants of the kinase genes. Taken together, our data demonstrate that the MKK4/5-MPK1/2 cascade plays a critical role in modulating SA signaling through a complex regulatory network in Arabidopsis.

Background and Objective: Climate change affecting on weather in many different ways especially drought and temperature rise. This will drastically down plant production, if not start looking for another source to increase water productivity to cope up with water stress conditions. In this study efforts were conducted to interpret the use of anti-transpirants to conserving irrigation water, aiding plant survival under dry conditions and protecting plant against drought stress., Materials and Methods: Two field experiments were carried out during 2017 and 2018 successive growing summer seasons at the experimental farm of National Research Centre, Nubaria, El-Beheira Governorate, Egypt. Anti-transparent ,i.e., chitosan (100 and 150 mg L-1), calcium carbonate (5 and 10 g L-1), salicylic acid (200 and 300 mg L-1) were foliar sprayed on sunflower plants grown under two water levels (normal 100% and deficit 50%)., Results: The results showed that water stress decreased growth criteria, photosynthetic pigments, osmoprotectants, yield components, oil and carbohydrate (%) as compared to 100% of irrigation requirements. Meanwhile, water deficit induced significant increases in (proline). Foliar treatments of sunflower plant with chitosan, calcium carbonate, salicylic acid increased growth criteria, yield components, photosynthetic pigments, total soluble sugars, proline and free amino acid as compared to control plant. Data also illustrated that, all used treatment improved seed yield, oil and carbohydrate% of sunflower plants., Conclusion: Generally, it could be concluded that 10 g L-1 CaCO3 and 300 mg L-1 SA at 50% level of water irrigation could be recommended for sunflower plant grown under similar field conditions in order to get optimum yield and to save irrigation water.

Epigenetic modifications have emerged as an important mechanism underlying plant defence against pathogens. We examined the role of JMJ14, a Jumonji (JMJ) domain-containing H3K4 demethylase, in local and systemic plant immune responses in Arabidopsis. The function of JMJ14 in local or systemic defence response was investigated by pathogen growth assays and by analysing expression and H3K4me3 enrichments of key defence genes using qPCR and ChIP-qPCR. Salicylic acid (SA) and pipecolic acid (Pip) levels were quantified and function of JMJ14 in SA- and Pip-mediated defences was analysed in Col-0 and jmj14 plants. jmj14 mutants were compromised in both local and systemic defences. JMJ14 positively regulates pathogen-induced H3K4me3 enrichment and expression of defence genes involved in SA- and Pip-mediated defence pathways. Consequently, loss of JMJ14 results in attenuated defence gene expression and reduced Pip accumulation during establishment of systemic acquired resistance (SAR). Exogenous Pip partially restored SAR in jmj14 plants, suggesting that JMJ14 regulated Pip biosynthesis and other downstream factors regulate SAR in jmj14 plants. JMJ14 positively modulates defence gene expressions and Pip levels in Arabidopsis., (© 2019 The Authors. New Phytologist © 2019 New Phytologist Trust.)

Salicylic acid (SA) and ethylene (ET) are important phytohormones that regulate numerous plant growth, development, and stress response processes. Previous studies have suggested functional interplay of SA and ET in defense responses, but precisely how these two hormones coregulate plant growth and development processes remains unclear. Our present work reveals antagonism between SA and ET in apical hook formation, which ensures successful soil emergence of etiolated dicotyledonous seedlings. Exogenous SA inhibited ET-induced expression of HOOKLESS1 ( HLS1 ) in Arabidopsis ( Arabidopsis thaliana ) in a manner dependent on ETHYLENE INSENSITIVE3 (EIN3) and EIN3-LIKE1 (EIL1), the core transcription factors in the ET signaling pathway. SA-activated NONEXPRESSER OF PR GENES1 (NPR1) physically interacted with EIN3 and interfered with the binding of EIN3 to target gene promoters, including the HLS1 promoter. Transcriptomic analysis revealed that NPR1 and EIN3/EIL1 coordinately regulated subsets of genes that mediate plant growth and stress responses, suggesting that the interaction between NPR1 and EIN3/EIL1 is an important mechanism for integrating the SA and ET signaling pathways in multiple physiological processes. Taken together, our findings illuminate the molecular mechanism underlying SA regulation of apical hook formation as well as the antagonism between SA and ET in early seedling establishment and possibly other physiological processes., (© 2020 American Society of Plant Biologists. All rights reserved.)

Different abiotic and biotic stresses lead to the production and accumulation of reactive oxygen species (ROS) in various cell organelles such as in mitochondria, resulting in oxidative stress, inducing defense responses or programmed cell death (PCD) in plants. In response to oxidative stress, cells activate various cytoprotective responses, enhancing the antioxidant system, increasing the activity of alternative oxidase and degrading the oxidized proteins. Oxidative stress responses are orchestrated by several phytohormones such as salicylic acid (SA). The biomolecule SA is a key regulator in mitochondria-mediated defense signaling and PCD, but the mode of its action is not known in full detail. In this review, the current knowledge on the multifaceted role of SA in mitochondrial ROS metabolism is summarized to gain a better understanding of SA-regulated processes at the subcellular level in plant defense responses.

Inhibition of cytochrome P450 (CYP) alters the pharmacokinetic parameters of the drug and causes drug-drug interactions. Salicylic acid been used for the treatment of colorectal cancer (CRC) and chemoprevention in recent decades. Thus, the aim of this study was to examine the in vitro inhibitory effect of salicylic acid on CYP2E1 activity in rat liver microsomes (RLMs) using high-performance liquid chromatography (HPLC). High-performance liquid chromatography analysis of a CYP2E1 assay was developed on a reversed phase C 18 column (SUPELCO 25 cm × 4.6 mm × 5 µm) at 282 nm using 60% H 2 O, 25% acetonitrile, and 15% methanol as mobile phase. The CYP2E1 assay showed a good linearity (R 2 > 0.999), good reproducibility, intra- and inter-day precision (<15%), acceptable recovery and accuracy (80-120%), and low detection (4.972 µM and 1.997 µM) and quantitation limit values (15.068 µM and 6.052 µM), for chlorzoxazone and 6-hydroxychlorzoxazone, respectively. Salicylic acid acts as a mixed inhibitor (competitive and non-competitive inhibition), with K i (inhibition constant) = 83.56 ± 2.730 µM and concentration of inhibitor causing 50% inhibition of original enzyme activity (IC 50 ) exceeding 100 µM (IC 50 = 167.12 ± 5.460 µM) for CYP2E1 enzyme activity. Salicylic acid in rats would have both low and high potential to cause toxicity and drug interactions with other drugs that are substrates for CYP2E1., Competing Interests: The authors declare no conflict of financial interest or any financial involvement with any company.

We, herein, report the effect of chitosan nanofertilizer comprising of copper (Cu) and salicylic acid (SA) on source activity in maize. Seed treatment and foliar application of chitosan nanofertilizer significantly up-regulated the source activity in developing maize plants. Seed treatment with nanofertilizer induced 1.6 folds higher seedling vigour index, 1.7-3.0 folds higher activities of reserve food mobilizing enzymes in seedlings as compared with control. Foliar application of nanofertilizer (0.01-0.16%) statistically significantly increased the activities of antioxidant enzymes (1.06-1.91 folds), reduced malondialdehyde content and enhanced chlorophyll contents (2 folds) in leaves. Application of nanofertilizer remarkably induced sucrose translocation (2.5-3.5 folds) in internodes which gives subtle clue of higher remobilization of nutrients towards growing cob. The elusive bioactivities of nanofertilizer can be attributed to slow release and synergistic effects of Cu and SA. We claim that chitosan nanofertilizer has immense potential to promote source activity in maize for higher crop yield., Competing Interests: Declaration of competing interest Authors declare that they do not have any financial conflict of interest., (Copyright © 2019 Elsevier B.V. All rights reserved.)

DEK involves in the modulation of cell proliferation, differentiation, apoptosis, migration and cell senescence. However, direct genetic evidence proving the functions of DEK in disease resistance against pathogens is still deficient. In the present study, four DEKs were identified in tomato genome and their roles in disease resistance in tomato were analyzed. The expression levels of DEKs were differently induced by Botrytis cinerea, Pseudomonas syringae pv. tomato (Pst) DC3000 and defense-related signaling molecules (such as jasmonic acid, aethylene precursor and salicylic acid). The DEKs' silencing by virus induced gene silencing led to decreased resistance against B. cinerea or Pst DC3000. The underlying mechanisms may be through the upregulation of the accumulation of reactive oxygen species (ROS) and the changed expression levels of defense-related genes by pathogen inoculation. These results indicate that DEKs involve in disease resistance against different pathogens and thus broaden the knowledge of DEK genes' function in tomato., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Salicylic acid (SA) is considered to play an important role in plant responses to environmental stresses. However, the detailed protective mechanisms in photosynthesis are still unclear. We therefore explored the protective roles of SA in photosystem II (PSII) in Arabidopsis thaliana under high light. The results demonstrated that 3 h of high light exposure resulted in a decline in photochemical efficiency and the dissipation of excess excitation energy. However, SA application significantly improved the photosynthetic capacity and the dissipation of excitation energy under high light. Western blot analysis revealed that SA application alleviated the decrease in the levels of D1 and D2 protein and increased the amount of Lhcb5 and PsbS protein under high light. Results from photoinhibition highlighted that SA application could accelerate the repair of D1 protein. Furthermore, the phosphorylated levels of D1 and D2 proteins were significantly increased under high light in the presence of SA. In addition, we found that SA application significantly alleviated the disassembly of PSII-LHCII super complexes and LHCII under high light for 3 h. Overall, our findings demonstrated that SA may efficiently alleviate photoinhibition and improve photoprotection by dissipating excess excitation energy, enhancing the phosphorylation of PSII reaction center proteins, and preventing the disassembly of PSII super complexes., Competing Interests: The authors declare no conflict of interest.

The evolution of adaptive interactions with beneficial, neutral and detrimental microbes was one of the key features enabling plant terrestrialization. Extensive studies have revealed conserved and unique molecular mechanisms underlying plant-microbe interactions across different plant species; however, most insights gleaned to date have been limited to seed plants. The liverwort Marchantia polymorpha, a descendant of early diverging land plants, is gaining in popularity as an advantageous model system to understand land plant evolution. However, studying evolutionary molecular plant-microbe interactions in this model is hampered by the small number of pathogens known to infect M. polymorpha. Here, we describe four pathogenic fungal strains, Irpex lacteus Marchantia-infectious (MI)1, Phaeophlebiopsis peniophoroides MI2, Bjerkandera adusta MI3 and B. adusta MI4, isolated from diseased M. polymorpha. We demonstrate that salicylic acid (SA) treatment of M. polymorpha promotes infection of the I. lacteus MI1 that is likely to adopt a necrotrophic lifestyle, while this effect is suppressed by co-treatment with the bioactive jasmonate in M. polymorpha, dinor-cis-12-oxo-phytodienoic acid (dn-OPDA), suggesting that antagonistic interactions between SA and oxylipin pathways during plant-fungus interactions are ancient and were established already in liverworts., (© The Author(s) 2019. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Banana is highly susceptible to low temperature and salicylic acid (SA) can effectively improve the chilling tolerance. The metabolic changes of SA induced chilling responses of banana were studied. Bananas normally ripened under 15 °C and dramatic metabolic difference compared with other groups was recorded. Accumulation of glucose (>1.5 folds) and consumption of unsaturated fatty acids (11.0-16.5%) were observed. The glycolysis was induced to compensate the decreased energy charge. Low temperature (6 °C) caused chilling damage and metabolites including glutamine, serine, and glucose were related to chilled bananas. Various physiological changes such as sugar metabolism and consumption of reducing substances occurred to adapt the cold stress. SA released the cold injury and the disaccharides were increased by 18.1-21.4%. Further analysis revealed the synthesis of unsaturated fatty acids, amino acids such as proline, and enhanced energy charge. Thus, SA increased the chilling tolerance via a number of different metabolic mechanisms., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

An experimentation was carried out to appraise whether or not nitric oxide (NO) contributes to salicylic acid (SA)-induced salinity tolerance particularly by regulating ascorbate-glutathione (AsA-GSH) cycle. Before starting salinity stress (SS), SA (0.5 mM) was sprayed to the foliage of plants once every other day for a week and then seedlings were grown under control or SS (100 mM NaCl), for five weeks. Salinity stress enhanced the AsA-GSH cycle-related enzymes, glutathione reductase (GR), ascorbate peroxidase (APX), and dehydroascorbate reductase (DHAR), and monodehydroascorbate reductase (MDHAR). Furthermore, SS caused substantial decreases in plant physiological-related traits such as leaf potassium (K) contents, K + /Na + ratio, the ratios of reduced ascorbate/dehydroascorbic acid (AsA/DHA) and reduced glutathione/oxidized glutathione (GSH/GSSG), but in contrast, significant increases occurred in leaf hydrogen peroxide, malondialdehyde, electron leakage, proline, the premier antioxidant enzymes' activities, Na + and NO. SA reduced leaf Na + content and oxidative stress-related traits, but improved all earlier-mentioned traits compared with those in plants treated with SS alone. All positive effects of SA were eliminated by NO scavenger, 0.1 mM 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1- oxyl-3-oxide (c-PTIO) by reducing NO, suggesting that NO produced by SA up-regulated the activities of AsA-GSH cycle and antioxidant enzymes, so it could play a central function as a signal molecule in salt tolerance of pepper plants., Competing Interests: Declaration of competing interest Authors declare no conflict of interest exists., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Problem: Oxidative stress and inflammation are key events leading to pre-eclampsia, involved in several maternal deaths. Low doses of acetylsalicylic acid (ASA) are used in the prevention and treatment of pre-eclampsia. The synthesis of aspirin-triggered lipoxin (ATL) by cyclooxygenase-2 acetylation is an alternative mechanism of ASA, which could explain the effectiveness of ASA treatments. The aim of this study was to evaluate the role of ASA, salicylates, and ATL in the modulation of the oxidative and inflammatory responses induced by plasma from women with pre-eclampsia., Method of Study: Plasma from 14 women with pre-eclampsia and 17 normotensive pregnant women was probed for inducing oxidative and inflammatory responses on endothelial cells and U937 promonocytes. The role of ATL, ASA, and salicylic acid (SA) on these events was evaluated., Results: Plasma from women with pre-eclampsia induced TBARS and nitrotyrosine production on endothelial and U937 cells. Pre-treatment with both ATL and ASA decreased the TBARS production, while ATL decreased the nitrotyrosine. Pre-eclamptic plasma augmented the translocation of NF-kB on U937 cells, which decreased by a high dose of ASA and SA. Finally, the pre-eclamptic plasma increased the adhesion of leukocytes-PMN and monocytes-to endothelium, and we were able to determine a state of resolution of inflammation, since ATL decreased the PMN adhesion, and conversely, it increased the monocytes adhesion to endothelium., Conclusion: Together, these results suggest that ATL could explain the beneficial actions of ASA and support further research on mechanisms, real efficacy, and rational use of ASA in pre-eclampsia., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

It is well known that parasitic weeds such as Orobanche (broomrape) significantly decrease crop growth and yield. Although hormonal priming is a well-known inducer of plant resistance against broomrapes (Orobanche spp.), the metabolic events associated with such resistance are poorly understood. Therefore, the current work was undertaken to elucidate the role of SA in inducing tomato resistance against Orobanche, considering its impact on carbon and nitrogen metabolism of the host. Total carbon and nitrogen and levels of carbon (sugars, organic acids and fatty acids) and nitrogen (amino acids and polyamines)-containing metabolites as well as the activities of some key enzymes involved in their metabolic pathways were evaluated. Broomrape infection significantly disrupted C/N ratio in the host roots. On contrary, SA treatment markedly induced accumulation of sugars, organic acids, fatty acids, amino acids as well as polyamines in healthy plants. Under broomrape challenge, SA mitigated the infection-induced growth inhibition by improving the level of nitrogen-containing osmoprotectants (proline, arginine and some polyamines). However, a decrease was observed in some C and N assimilates which are well known to be potentially transferred to the parasite, such as sucrose, asparagine, alanine, serine and glutamate. Interestingly, SA treatment induced the catapolism of polyamines and fatty acids in the host root. Accordingly, our study suggests that SA-induced resistance against broomrape relies on the rational utilization of C and N assimilates in a manner that disturbs the sink strength of the parasite and/or activates the defense pool of the host., Competing Interests: Declaration of competing interest The authors have declared no conflict of interest., (Copyright © 2019. Published by Elsevier Masson SAS.)

Salinity represents a serious environmental threat to crop production and by extension, to world food supply, social and economic prosperity of the developing world. Salicylic acid (SA) is an endogenous plant signal molecule involved in regulating various plant responses to stress. In the present study, we characterized the regulatory role of exogenous SA for their ability to ameliorate deleterious effects of salt stress (0, 100, 150, 200 mM NaCl) in choysum plants through coordinated induction of antioxidants, ascorbate glutathione (AsA-GSH) cycle, and the glyoxalase enzymes. An increase in salt stress dramatically declined root and shoot growth, leaf chlorophyll and relative water content (RWC), subsequently increased electrolyte leakage (EL) and osmolytes accumulation in choysum plants. Salt stress disrupted the antioxidant and glyoxalase defense systems which persuaded oxidative damages and carbonyl toxicity, indicated by increased H 2 O 2 generation, lipid peroxidation, and methylglyoxal (MG) content. However, application of SA had an additive effect on the growth of salt-affected choysum plants, which enhanced root length, plant biomass, chlorophyll contents, leaf area, and RWC. Moreover, SA application effectively eliminated the oxidative and carbonyl stress by improving AsA and GSH pool, upregulating the activities of antioxidant enzymes and the enzymes associated with AsA-GSH cycle and glyoxalase system. Overall, SA application completely counteracted the salinity-induced deleterious effects of 100 and 150 mM NaCl and partially mediated that of 200 mM NaCl stress. Therefore, we concluded that SA application induced tolerance to salinity stress in choysum plants due to the synchronized increase in activities of enzymatic and non-enzymatic antioxidants, enhanced efficiency of AsA-GSH cycle and the MG detoxification systems., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Triclosan (TCS) is a chlorophenol which is highly bacteriostatic and used in a wide array of consumer products. TCS is now one of the most commonly detected organic pollutants in the sewage sludges. The sludge utilization for fertilizers on agricultural land would pose the risk of causing adverse effects on plant growth and yield by TCS. However, the toxicity of TCS toward plants is comparatively less understood. In this study, we assessed the effects of TCS on tobacco plants which were grown in MS medium or soils containing various concentrations of TCS. Our results indicated that TCS at the concentration of 2 mg/L could strongly inhibit the tobacco seed germination. TCS could suppress tobacco plant growth in soil with different concentrations (10, 20, and 50 mg/kg) of TCS through the downregulation of chlorophyll contents, restricting photosynthesis and increasing generation of reactive oxygen species (ROS). Salicylic acid (SA) plays important roles in the stress response of plants. The role of exogenous SA application in protecting tobacco plants from TCS stress was also investigated in this study. SA application could significantly increase net photosynthesis, enhance antioxidant enzyme activity, and thereby enhancing tobacco plant tolerance to TCS. Moreover, the activation of MPK3 and MPK6 induced by TCS was downregulated in plants with the treatment of SA. It was thus referred that mitogen-activated protein kinases (MAPKs) might play a key role in the signal transduction of TCS stress, and this process might be regulated by SA signaling. Overall, our results demonstrated that TCS had negative impacts on tobacco plants and SA played a protective role on tobacco plants against TCS stress.

Phytohormones play a crucial role in regulating plant developmental processes. Among them, ethylene and jasmonate are known to be involved in plant defense responses to a wide range of biotic stresses as their levels increase with pathogen infection. In addition, these two phytohormones have been shown to inhibit plant nodulation in legumes. Here, exogenous salicylic acid (SA), jasmonate acid (JA), and ethephon (ET) were applied to the root system of Casuarina glauca plants before Frankia inoculation, in order to analyze their effects on the establishment of actinorhizal symbiosis. This protocol further describes how to identify putative ortholog genes involved in ethylene and jasmonate biosynthesis and/or signaling pathways in plant, using the Arabidopsis Information Resource (TAIR), Legume Information System (LIS), and Genevestigator databases. The expression of these genes in response to the bacterium Frankia was analyzed using the gene atlas for Casuarina-Frankia symbiosis (SESAM web site).

The present study was carried out to investigate the beneficial role of exogenous application of salicylic acid (1 mM SA) and nitric oxide (100 μM NO) in preventing the oxidative damage in Vigna angularis triggered by salinity stress. Salinity (100 mM NaCl) stress reduced growth, biomass accumulation, chlorophyll synthesis, photosynthesis, gas exchange parameters, and photochemical efficiency (Fv/Fm) significantly. Exogenous application of SA and NO was affective in enhancing these growth and photosynthetic parameters. Salinity stress reduced relative water content over control. Further, the application of SA and NO enhanced the synthesis of proline, glycine betaine, and sugars as compared to the control as well as NaCl treated plants contributing to the maintenance of tissue water content. Exogenous application of SA and NO resulted in up-regulation of the antioxidant system. Activities of enzymatic antioxidants including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), and glutathione reductase (GR), as well as the content of non-enzymatic components, were more in SA + NO treated seedlings as compared to control and salinity stressed counterparts resulting in significant alleviation of the NaCl mediated oxidative damage. Content of nitrogen, potassium, and calcium increased due to SA and NO under normal conditions and NaCl stress conditions while as Na and Cl content reduced significantly., Competing Interests: The authors declare no conflict of interest.

Alkalinity is a known threat to crop plant growth and production, yet the role of exogenous silicon (Si) and salicylic acid (SA) application has been largely unexplored. Here, we sought to understand the beneficial impacts of Si and SA on tomato seedlings during high-pH (9.0) stress. Results showed that Si- and SA-treated plants displayed higher biomass, chlorophyll contents, relative leaf water and better root system than none-treated plants under alkaline conditions. Both Si and SA counteracted the alkaline stress-induced oxidative damage by lowering the accumulation of reactive oxygen species and lipid peroxidation. The major antioxidant defence enzyme activities were largely stimulated by Si and SA, and these treatments caused significantly increased K + and lowered Na + concentrations in shoot and root under stress. Moreover, Si and SA treatments modulated endogenous SA levels and dramatically decreased abscisic acid levels in both shoot and root. Additionally, key genes involved in Si uptake, SA biosynthesis, the antioxidant defence system and rhizosphere acidification were up-regulated in Si and SA treatments under alkaline conditions. These results demonstrate that Si and SA play critical roles in improving alkaline stress tolerance in tomato seedlings, by modifying the endogenous Na + and K + contents, regulating oxidative damage and key genes and modulating endogenous hormone levels. These findings will help to broaden our understanding regarding the physiological and molecular mechanisms associated with the alkaline soil tolerance in plants.

The effects of plant inoculation with plant growth-promoting rhizobacteria (PGPR) and those resulting from the exogenous application of salicylic acid (SA) or methyl jasmonte (MeJA) on total phenolic content (TPC) and monoterpenes in Mentha x piperita plants were investigated. Although the PGPR inoculation response has been studied for many plant species, the combination of PGPR and exogenous phytohormones has not been investigated in aromatic plant species. The exogenous application of SA produced an increase in TPC that, in general, was of a similar level when applied alone as when combined with PGPR. This increase in TPC was correlated with an increase in the activity of the enzyme phenylalanine ammonia lyase (PAL). Also, the application of MeJA at different concentrations in combination with inoculation with PGPR produced an increase in TPC, which was more relevant at 4 mM, with a synergism effect being observed. With respect to the main monoterpene concentrations present in peppermint essential oil (EO), it was observed that SA or MeJA application produced a significant increase similar to that of the combination with rhizobacteria. However, when plants were exposed to 2 mM MeJA and inoculated, an important increase was produced in the concentration on menthol, pulegone, linalool, limonene, and menthone concentrations. Rhizobacteria inoculation, the treatment with SA and MeJA, and the combination of both were found to affect the amount of the main monoterpenes present in the EO of M. piperita . For this reason, the expressions of genes related to the biosynthesis of monoterpene were evaluated, with this expression being positively affected by MeJA application and PGPR inoculation, but was not modified by SA application. Our results demonstrate that MeJA or SA application combined with inoculation with PGPR constitutes an advantageous management practice for improving the production of secondary metabolites from M. piperita ., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

The protease inhibitors (PIs) in plants are involved primarily in defense against pathogens and pests and in response to abiotic stresses. However, information about the PI gene families in tomato ( Solanum lycopersicum ), one of the most important model plant for crop species, is limited. In this study, in silico analysis identified 55 PI genes and their conserved domains, phylogenetic relationships, and chromosome locations were characterized. According to genetic structure and evolutionary relationships, the PI gene families were divided into seven families. Genome-wide microarray transcription analysis indicated that the expression of SlPI genes can be induced by abiotic (heat, drought, and salt) and biotic ( Botrytis cinerea and tomato spotted wilt virus (TSWV)) stresses. In addition, expression analysis using RNA-seq in various tissues and developmental stages revealed that some SlPI genes were highly or preferentially expressed, showing tissue- and developmental stage-specific expression profiles. The expressions of four representative SlPI genes in response to abscisic acid (ABA), salicylic acid (SA), ethylene (Eth), gibberellic acid (GA). and methyl viologen (MV) were determined. Our findings indicated that PI genes may mediate the response of tomato plants to environmental stresses to balance hormone signals. The data obtained here will improve the understanding of the potential function of PI gene and lay a foundation for tomato breeding and transgenic resistance to stresses., Competing Interests: The authors declare no conflict of interest.

Developing protein tyrosine phosphatase-1B (PTP1B) inhibitors is an important strategy to treat type 2 diabetes mellitus (T2DM). Most existing ionic PTP1B inhibitors aren't of clinical useful due to their low cell-permeability, however. Herein, we introduced a series of lipid-like acid-based (salicylic acid) modules to prepare PTP1B inhibitors, and demonstrated a marked improvement of cell-permeability while maintaining excellent PTP1B inhibitory activity (e.g. compound B12D, IC 50  = 0.37 μM against PTP1B and P app  = 1.5 × 10 -6  cm/s). We believe that this strategy can be widely utilized to modify potent lead compounds with low cell-permeability., (Copyright © 2019 Elsevier Inc. All rights reserved.)