Salicylic Acid Content Research Articles

Salicylic acid altered the fatty acids compositions and nutrient status of shallot (Allium hirtifolium) grown under drought stress

In arid and semi-arid regions, water shortage is a persistent challenge, significantly affecting plant growth and productivity. To mitigate the detrimental effects of drought, the use of plant growth regulators, such as salicylic acid (SA), has proven to be an effective strategy for enhancing plant resilience, as well as improving yield and quality. This study aimed to investigate the impact of SA on the nutrient composition, yield, and overall quality of shallot plants over three cropping seasons (2020, 2021, and 2022) under drought stress conditions. A split-plot design with four replicates was employed, where irrigation levels (0 %, 50 %, 75 %, and 100 % of the plant's water requirements) were the main factor, and varying concentrations of SA (0, 0.5, 0.75, and 1 mM) were the secondary factor. The results revealed that drought stress increased the concentrations of key micronutrients—iron, copper, sodium, potassium, manganese, and zinc—while reducing magnesium content, ash content, and overall yield. However, the application of SA counteracted these effects by significantly enhancing magnesium content, ash content, and yield in shallot plants. In addition, drought stress increased the levels of palmitic, palmitoleic, and oleic acids while reducing the levels of stearic, linoleic, and linolenic acids. The highest concentrations of linoleic acid (ω6, 110.1 mg) and linolenic acid (ω3, 24.242 mg) were recorded under full irrigation and 75 % water requirement treatments, respectively. SA application further enhanced the levels of stearic, oleic, and linoleic acids, improving the overall nutritional quality of shallot plants. In conclusion, the application of optimal concentrations of SA significantly improves the yield, quality, and nutritional value of shallot plants under drought stress, making it a valuable approach for managing water stress in agriculture.

Integrative multi-omics analysis of chilling stress in pumpkin (Cucurbita moschata).

Pumpkin (Cucurbita moschata) is an important vegetable crop that often suffers from low-temperature stress during growth. However, the molecular mechanism involved in its response to chilling stress remains unknown. In this study, we comprehensively investigated the effect of chilling stress in pumpkin seedlings by conducting physiological, transcriptomic, and metabolomic analyses. Under chilling stress, there was an overall increase in relative electrical conductivity, along with malondialdehyde, soluble sugar, and soluble protein contents, but decreased superoxide dismutase and peroxidase activities and chlorophyll contents in seedling leaves compared with controls. Overall, 5,780 differentially expressed genes (DEGs) and 178 differentially expressed metabolites (DEMs) were identified under chilling stress. Most DEGs were involved in plant hormone signal transduction and the phenylpropanoid biosynthesis pathway, and ERF, bHLH, WRKY, MYB, and HSF transcription factors were induced. Metabolomic analysis revealed that the contents of salicylic acid (SA), phenylalanine, and tyrosine increased in response to chilling stress. The findings indicated that the SA signaling and phenylpropanoid biosynthesis pathways are key to regulating the responses to chilling stress in pumpkins. Overall, our study provides valuable insights into the comprehensive response of C. moschata to chilling stress, enriching the theoretical basis of this mechanism and facilitating the development of molecular breeding strategies for pumpkin tolerance to chilling stress.

Exogenous Salicylic Acid Regulates Fruiting Body Development, Secondary Metabolite Accumulation, Cell Wall Integrity, and Endogenous Salicylic Acid Content under Heat Stress in Pleurotus ostreatus.

High-temperature or heat stress (HS) represents a significant environmental challenge that adversely affects crop growth and poses a substantial threat to agricultural production. Pleurotus ostreatus, recognized as the second most widely cultivated edible fungus worldwide, is particularly susceptible to the detrimental effects of HS. Enhancing the HS resistance of P. ostreatus is crucial for increasing its yield. In a prior investigation, we discovered that salicylic acid (SA) enhanced the resistance of P. ostreatus mycelia to HS through a metabolic rearrangement. The present study further investigated the effects of SA on P. ostreatus under HS. Cultivation experiments revealed that exogenous SA improved the mycelium recovery growth rate, yield, and fruiting body quality after HS. Further experiments revealed that exogenous SA mitigated the damage to the MAPK-Slt2 signal produced by HS while maintaining cell wall integrity. Furthermore, we hypothesized that the phenylalanine ammonia-lyase pathway might serve as a source for SA. In this context, we identified two salicylic hydroxylases, Po1102164 and Po1104438. Both HS and exogenous SA were found to elevate intracellular SA levels, thereby enhancing the resistance of P. ostreatus to HS.

The Role of Salicylic Acid in Salinity Stress Mitigation in Dizygostemon riparius: A Medicinal Species Native to South America.

Salicylic acid (SA) is a bioregulator well-known for mitigating salinity damage in plants. However, no studies have examined the interaction between SA and salinity in Dizygostemon riparius, a species rich in bioactive molecules. Therefore, we aimed to evaluate the effect of SA application on Dizygostemon riparius under different salinity levels. A completely randomized experiment was conducted in a 2 × 3 factorial design (two SA concentrations of 0 and 100 µM and three salinity concentrations of 0, 200, and 400 mM NaCl) with five replicates. At 400 mM NaCl, leaf temperature increased by 11%, while relative water content and total soluble carbohydrates decreased by 30% and 35%, respectively, leading to reduced biomass accumulation. Notably, the SA application mitigated these effects by restoring relative water content under 400 mM NaCl and improving carboxylation efficiency and intrinsic water-use efficiency under 200 mM NaCl. Additionally, dry biomass was maintained under both 200 and 400 mM NaCl with SA treatment. These findings suggest that SA has a promising potential to alleviate salt stress in Dizygostemon riparius. Our results could inform cultivation practices, opening new perspectives on the use of SA as an attenuator of salinity stress.

Seasonal Changes in Salicylic and Jasmonic Acid Levels in Poplar with Differing Stress Responses

Poplars are essential tree species with critical roles in wood production, ecological conservation, environmental protection, and climate change mitigation. Plants of different poplar populations exhibit varying responses to biotic and abiotic stresses, largely driven by phytohormones—key regulators of plant growth and stress responses. Phytohormones control fundamental processes such as cell division, growth, tissue differentiation, organ development, and resistance to environmental challenges such as temperature extremes and drought. In this study, we conducted a quantitative analysis of phytohormone levels in the leaves of two populations of poplar species from the same geographical region over a one-year period, covering the early, mid, and late growth stages. Our results revealed that salicylic acid (SA) and jasmonic acid (JA) concentrations in the stress-resistant poplar (RP) increased significantly during the late growth stage (September), particularly in response to elevated pathogen pressure and fluctuating climatic conditions. In contrast, the susceptible poplar (SP) consistently exhibited lower levels of SA and JA across all growth stages, particularly during the mid-growth stage (characterized by high temperatures and low precipitation) and the late growth stage, when pathogen stress typically intensifies. The limited increase in phytohormone levels in the SP suggests a weaker defense response compared with the RP. These findings demonstrate that climatic factors significantly influence the phytohormonal dynamics in poplars, with the RP exhibiting more robust regulation of SA and JA to mitigate both biotic and abiotic stresses. This study provides a theoretical framework for better understanding the resistance mechanisms in Populus and offers insights for improving stress tolerance in future breeding programs.

Establishment of numerical model for precooling broccoli with ice water integrated with salicylic acid and its effect on broccoli apparent quality

Postharvest precooling is crucial for delaying yellowing of broccoli efficiently removing field heat. In this experiment, a numerical model for ice water precooling broccoli was established, and based on this, the main precooling parameters were optimized. Furthermore, the appropriate concentration of salicylic acid (SA) in the process of ice water integrated with SA precooling was determined. Through numerical simulation and experimental validation, the ice water precooling treatment with a 30 % ice volume fraction and a 1:1 mass ratio of ice water to broccoli was identified as optimal for achieving the best precooling uniformity and meeting the specified temperature requirements. Application of 2 mmol L-1 SA integrated with ice water precooling treatment effectively delayed yellowing, and maintained the apparent quality of broccoli, manifested as a higher h° value (chromaticity value) and chlorophyll content, a lower yellowing index. The shelf life of the treated broccoli was extended by 3 d

Isolation and Identification of Multi-Traits PGPR for Sustainable Crop Productivity Under Salinity Stress

High salinity poses a significant threat to arable land globally and contributes to desertification. Growth-promoting rhizobacteria assist plants in mitigating abiotic stresses and enhancing crop productivity through the production of siderophores, exopolysaccharides (EPS), solubilisation of phosphate, indole-3-acetic acid (IAA), and other secondary metabolites. This study aimed to isolate, identify, and characterise bacteria that exhibit robust growth-promoting properties. A total of 64 bacterial isolates from the rhizosphere of Miscanthus sinensis were evaluated for plant growth-promoting (PGP) traits, including IAA, EPS, siderophores, and solubilisation of phosphate. Among them, five isolates were selected as plant growth-promoting rhizobacteria (PGPR) based on their PGP features and identified via 16S rRNA sequencing: Enterococcus mundtii strain INJ1 (OR122486), Lysinibacillus fusiformis strain INJ2 (OR122488), Lysinibacillus sphaericus strain MIIA20 (OR122490), Pseudomonas qingdaonensis strain BD1 (OR122487), and Pseudomonas qingdaonensis strain MIA20 (OR122489), all documented in NCBI GenBank. BD1 demonstrated a higher production of superoxide dismutase (SOD) (17.93 U/mg mL), catalase (CAT) (91.17 U/mg mL), and glutathione (GSH) (0.18 U/mg mL), along with higher concentrations of IAA (31.69 µg/mL) and salicylic acid (SA) (14.08 ng/mL). These isolates also produced significant quantities of amino and organic acids. BD1 exhibited superior PGP traits compared to other isolates. Furthermore, the NaCl tolerance of these bacterial isolates was assessed by measuring their growth at concentrations ranging from 0 to 200 mM at 8-h intervals. Optical density (OD) measurements indicated that BD1 and INJ2 displayed significant tolerance to salt stress. The utilisation of these isolates, which enhances plant growth and PGP traits under salt stress, may improve plant development under saline conditions.

Spectrometric method for simultaneous quantification of nadifloxacin and salicylic acid in a novel topical dosage form

Acne vulgaris is a prevalent skin disorder that affects many individuals. In the search for effective acne therapy, researchers have found that a combination of Nadifloxacin and Salicylic Acid may produce a synergistic effect. To further investigate this, a study was conducted to devise a spectrophotometric method for simultaneously measuring the concentrations of Nadifloxacin and Salicylic Acid in a novel topical formulation. Simultaneous Estimation Method was employed using methanol as the solvent. Nadifloxacin exhibited an absorbance maximum of 291 nm, while Salicylic Acid showed an absorbance maximum of 297 nm in methanol. Linearity experiments were conducted to determine the concentration ranges for both drugs, which were found to be 2–12 ppm for Nadifloxacin and 5–30 ppm for Salicylic Acid. The recovery results of Nadifloxacin ranged from 82 % to 95 %, while those of Salicylic Acid ranged from 97 % to 110 %. These results indicate the accuracy and reliability of the method. This method was further validated in accordance with the guidelines provided by the International Council for Harmonization (ICH) of Technical Requirements for Human Use. The proposed method has demonstrated its applicability for the simultaneous and quantitative assessment of Nadifloxacin and Salicylic Acid in various dosage forms. This development is significant as it provides a reliable and efficient means of measuring the concentrations of these two drugs in acne therapy formulations.

Phytohormones and Mineral Nutrient Changes in Young Plants of Grapevine Genotypes at Different Growth Stages

Climate change is considered a threat for viticulture by altering phenology, yield, and key physiological processes. The plant responses depend on the genotype characteristics and the microclimate of crop area. In this research, “Castellana Negra”, “Negramoll”, and “Tintilla” were cultivated for 102 days, and physiological variables were assessed under natural conditions. Results indicated similar trends in growth between “Negramoll” and “Tintilla”, while ”Castellana Negra” grew slowly and possessed fewer leaves compared to the other genotypes. Stomatal conductance was constant among the genotypes, excepting “Negramoll”, which demonstrated lower values at d 76 compared to “Castellana Negra” and “Tintilla”, coinciding with the elevated leaf temperature. Regarding the hormonal changes, “Castellana Negra” accumulated the highest concentration of salicylic acid (SA) compared to “Negramoll” and “Tintilla”, which showed similar content. Furthermore, an antagonistic change between SA and jasmonic acid (JA) was observed in all genotypes, as well as between abscisic acid (ABA) and JA at the beginning and end of the trial. The variations in micronutrients did not show a clear tendency between cultivars. Therefore, to thoroughly elucidate the role of phytohormones and other physiological factors in the growth and development of these genotypes under varying environmental conditions, long-term experiments could be conducted.

Regulation of Physiological and Biochemical Mechanisms Related to Water Stress Tolerance in Barley and Improvement of Growth and Productivity Using Salicylic Acid and Chitosan

The present investigation aimed to assess the impacts of three Salicylic Acid (SA) concentrations (T2=100, T3=200, T4=300ppm), three Chitosan concentrations (T5=150, T6=225, T7=300ppm) and T8= Salicylic Acid (100 ppm) with Chitosan (150 ppm) mixture in comparison to control treatment (T1) on two barley cultivars Giza126 and Giza 134 under rainfed conditions. Some vegetative and yield traits were recorded, plant height, spike length, number of gains spike-1, number of spikes/m2, 1000 grain weight, biological and grain yield. A split plot design was performed with three replications. The field experiment was conducted in the northern west coast region of Egypt (Marsa Matruh government) under the rainfed condi­tions during 2019/2020 and 2020/2021 growing seasons. The results showed a direct relationship between increased foliar application and increased yield attributes. Results indicated that Giza 126 cultivar as affected by T4 showed the most desirable values for grains spikes-1 in first season, spikes/m2, biological yield and grain yield during the first and second seasons respectively. In addition, barley cultivar Giza 126 as affected by T3 showed the highest values for grains spikes-1 in second season. On the other hand, barley cultivar Giza 134 as affected by T4 showed the highest values for plant height, spike length and 1000-grain weight in first and second seasons respectively. From results, it can be concluded that the Salicylic Acid (SA) concentration 300 ppm is recommendable for improving the productivity of barley under rainfed conditions of Egypt. To study the potential role of SA and Chitosan on water stress tolerance mechanisms some biochemical and physiological parameters were recorded. Application of SA and Chitosan decreased significantly Reactive Oxygen Species (ROS) measuring by determined the concentrations of MDA and H2O2 especially SA with concentrations 300 ppm (T4). For osmolytes (proline, SSC and SPC), all treatments using SA and Chitosan induced significant increase in osmolytes content compared with control under water stress only in the two studied barley genotypes, except for treatment with Chitosan 225 and 300 ppm in Giza 126 for proline content. Similar results were recorded for antioxidant enzymes activity (CAT, POX and PPO) which showed up-regulation for all treatments compared with control under water stress for the two studied genotypes. On contrast, APX antioxidant enzyme recorded the highest activity in control treatment under water stress only. In general, for all studied treatments comparing with control, application of SA300 ppm and the mixture between SA100 and Chitosan150 ppm were the best treatment for induction of up and down regulation of biochemical and physiological component in the barley cells which is known as defense system against water stress damage.

Overexpressing CsSABP2 enhances tolerance to Huanglongbing and citrus canker in C. sinensis.

Huanglongbing (HLB) and citrus canker, arising from Candidatus Liberibacter asiaticus (CaLas) and Xanthomonas citri pv. Citri (Xcc), respectively, have been imposing tremendous losses to the global citrus industry. Systemic acquired resistance (SAR) has been shown to be crucial for priming defense against pathogen in citrus. Salicylic acid (SA) binding protein 2 (SABP2), which is responsible for converting methyl salicylate (MeSA) to SA, is essential for full SAR establishment. Here, we characterized the functions of four citrus SABP2 genes (CsSABP2-1, CsSABP2-1V18A , CsSABP2-2 and CsSABP2-3) against HLB and citrus canker. In vitro enzymatic assay revealed that all four proteins had MeSA esterase activities, and CsSABP2-1 and CsSABP2-1V18A has the strongest activity. Their activities were inhibited by SA except for CsSABP2-1V18A. Four genes controlled by a strong promoter 35S were induced into Wanjincheng orange (Citrus sinensis Osbeck) to generate transgenic plants overexpressing CsSABP2. Overexpressing CsSABP2 increased SA and MeSA content and CsSABP2-1V18A had the strongest action on SA. Resistance evaluation demonstrated that only CsSABP2-1V18A had significantly enhanced tolerance to HLB, although all four CsSABP2s had increased tolerance to citrus canker. The data suggested the amino acid Val-18 in the active site of CsSABP2 plays a key role in protein function. Our study emphasized that balancing the levels of SA and MeSA is crucial for regulating SAR and conferring broad-spectrum resistance to HLB and citrus canker. This finding offers valuable insights for enhancing resistance through SAR engineering.

Effects of Salicylic Acid on Physiological Responses of Pepper Plants Pre-Subjected to Drought under Rehydration Conditions.

Capsicum annuum L. has worldwide distribution, but drought has limited its production. There is a lack of research to better understand how this species copes with drought stress, whether it is reversible, and the effects of mitigating agents such as salicylic acid (SA). Therefore, this study aimed to understand the mechanisms of action of SA and rehydration on the physiology of pepper plants grown under drought conditions. The factorial scheme adopted was 3 × 4, with three water regimes (irrigation, drought, and rehydration) and four SA concentrations, namely: 0 (control), 0.5, 1, and 1.5 mM. This study evaluated leaf water percentage, water potential of shoots, chlorophylls (a and b), carotenoids, stomatal conductance, chlorophyll a fluorescence, and hydrogen peroxide (H2O2) concentration at different times of day, water conditions (irrigation, drought, and rehydration), and SA applications (without the addition of a regulator (0) and with the addition of SA at concentrations equal to 0.5, 1, and 1.5 mM). In general, exogenous SA application increased stomatal conductance (gs) responses and modified the fluorescence parameters (ΦPSII, qP, ETR, NPQ, D, and E) of sweet pepper plants subjected to drought followed by rehydration. It was found that the use of SA, especially at concentrations of 1 mM in combination with rehydration, modulates gs, which is reflected in a higher electron transport rate. This, along with the production of photosynthetic pigments, suggests that H2O2 did not cause membrane damage, thereby mitigating the water deficit in pepper plants. Plants under drought conditions and rehydration with foliar SA application at concentrations of 1 mM demonstrated protection against damage resulting from water stress. Focusing on sustainable productivity, foliar SA application of 1 mM could be recommended as a technique to overcome the adverse effects of water stress on pepper plants cultivated in arid and semi-arid regions.

Callose and Salicylic Acid Are Key Determinants of Strigolactone-Mediated Disease Resistance in Arabidopsis

Research has demonstrated that strigolactones (SLs) mediate plant disease resistance; however, the basal mechanism is unclear. Here, we provide key genetic evidence supporting how SLs mediate plant disease resistance. Exogenous application of the SL analog, rac-GR24, increased Arabidopsis thaliana resistance to virulent Pseudomonas syringae. SL-biosynthetic mutants and overexpression lines of more axillary growth 1 (MAX1, an SL-biosynthetic gene) enhanced and reduced bacterial susceptibility, respectively. In addition, rac-GR24 promoted bacterial pattern flg22-induced callose deposition and hydrogen peroxide production. SL-biosynthetic mutants displayed reduced callose deposition but not hydrogen peroxide production under flg22 treatment. Moreover, rac-GR24 did not affect avirulent effector-induced cell death between Col-0 and SL-biosynthetic mutants. Furthermore, rac-GR24 increased the free salicylic acid (SA) content and significantly promoted the expression of pathogenesis-related gene 1 related to SA signaling. Importantly, rac-GR24- and MAX1-induced bacterial resistance disappeared completely in Arabidopsis plants lacking both callose synthase and SA. Taken together, our data revealed that callose and SA are two important determinants in SL-mediated plant disease resistance, at least in Arabidopsis.

A randomised crossover design study comparing the pharmacokinetics and pharmacodynamics of two single Doses of ORal Aspirin (75 mg v 150mg) in pregnant women at risk of pre-eclampsia (DORA): implications on assessing aspirin response and patient adherence to therapy.

BackgroundPregnancy is associated with physiological changes that can alter the pharmacokinetic and pharmacodynamic profile of many drugs. Low-dose aspirin is used for pre-eclampsia (PE) prevention; however aspirin's pharmacokinetics and pharmacodynamics are poorly studied in pregnant women. ObjectiveThe aim of this study was to compare the pharmacodynamics of two common doses of aspirin (75 and 150 mg) used for PE prevention in high-risk women by examining their effect on thromboxane B2 (TbxB2) inhibition. A secondary objective sought to assess if salicylic acid could be used as means to evaluate adherence to aspirin. Study DesignFourteen pregnant women from a large maternity unit in England, eligible for prophylactic aspirin according to NICE guidance, were recruited into 2 x 2 randomised crossover trial. Blood samples were collected at baseline, 1, 2, 3, 4, 15, 16, 17, 18 and 19-hours post ingestion of either 75 or 150 mg of aspirin with a 7-day washout period. Plasma concentrations of salicylic acid (SA), the primary metabolite of aspirin, were determined using high performance liquid chromatography. Pharmacodynamic response to aspirin was assessed by measuring serum thromboxane B2 (TbxB2) concentrations by an enzyme-linked immunosorbent assay. Analyte data were compared using nonparametric test statistics for paired values (Wilcoxon Signed Rank Test) and areas under serum SA concentration versus time curve (AUC). Pharmacokinetic modelling was used to bridge the data arising from the overnight sampling break.The trial was registered with the ISRCTN (reg number ISRCTN14693054). ResultsA single dose of 150 mg of aspirin produced higher plasma exposure of SA in comparison to 75 mg (median SA AUC0-19 16.7 μg*h/ml (IQR 15.2-19.3) vs 6.8 μg*h/ml (IQR 6.1- 8.3), p<0.001). Pharmacokinetic models suggest that plasma SA concentrations could be detected above the maximum concentration recorded at baseline for the first 11 hours after 75 mg and for 12 hours after 150 mg aspirin dosing, providing a time frame to confirm recent aspirin ingestion. The 150 mg aspirin dose produced a greater normalised reduction in serum TbxB2 (median normalised reduction 95.7% (IQR 92.6%- 97.3%) than the 75 mg dose (median normalised reduction 84.6% (IQR 77.3-92.3%), p<0.007. ConclusionCompared to the 75 mg dose, 150 mg of aspirin more effectively inhibits TbxB2, providing rationale for further investigation of effectiveness of higher doses for pre-eclampsia prevention. Despite limitations, measuring serum SA concentration could still be used in future models to test adherence if done within 11-12 hours after ingestion.

Metabolomics reveals a key role of salicylic acid in embryo abortion underlying interspecific hybridization between Hydrangea macrophylla and H. arborescens.

Embryo abortion at the heart-shaped stage is the main reason for the failure of interspecific hybridization of hydrangea, and salicylic acid plays a key role during embryo abortion. Difficulties in obtaining seeds from interspecific hybridization between Hydrangea macrophylla and H. arborescens had severely restricted the process of breeding new hydrangea varieties. To clarify the cause of reproductive barriers, an interspecific hybridization was made between H. macrophylla 'Endless Summer' (female parent) and H. arborescens 'Annabelle' (male parent). The results showed that both parents' floral organs developed normally, 'Annabelle' had high pollen viability (84.83% at 8h after incubation), and the pollen tube could enter into the ovule of 'Endless Summer' at 72h after pollination. Therefore, the pre-fertilization barrier was not the main reason for the failure of interspecific hybridization. However, observation of the embryo development by paraffin sections showed that the embryo was aborted at the heart-shaped stage. In addition, salicylic acid (SA) content was significantly higher (fourfold, P < 0.01) at 21 days after pollination (DAP) as compared to that of 17 DAP, which means SA may be closely correlated with embryo development. A total of 957 metabolites were detected, among which 78 were significantly different. During the embryo abortion, phenylpropanoids and polyketides were significantly down-regulated, while organic oxygen compounds were significantly up-regulated. Further analysis indicated that the metabolic pathway was enriched in the shikimic acid biosynthesis pathway, which suggests that more SA was synthesized. Taken together, it can be reasonably speculated that SA plays a key role leading to embryo abortion underlying the interspecific hybridization between Hydrangea macrophylla and H. arborescens. The result is helpful to direct the breeding of hydrangea through distant hybridization.

Induced resistance to control postharvest stem-end rot by methyl jasmonate in mango fruit

Induced resistance is an alternative disease control strategy for postharvest fruits and vegetables. Methyl jasmonate (MeJA) is a crucial phytohormone in the defense response to biotic and abiotic stresses. The effect and relevant mechanism of MeJA on the control of postharvest disease in mango fruit remain unclear. This study investigated the effect and possible mechanism of MeJA against stem-end rot caused by Lasiodiplodia theobromae in mango fruit. The results showed that MeJA significantly inhibited the lesion expansion on mango fruit inoculated with L. theobromae. 10 μM MeJA treatment effectively induced disease resistance against L. theobromae during postharvest storage. MeJA enhanced the activities of defense-related enzymes, including phenylalanine ammonia lyase (PAL), peroxidase (POD), β-1,3-glucanase (GLU), and chitinase (CHT), increased the accumulation of endogenous jasmonic acid (JA) and salicylic acid (SA) contents, up-regulated the expressions of the related genes on JA pathway (AOS, JAR1, MYC2, and COI1) and SA pathway (ICS, and PR1), stimulated the contents of total phenolics and flavonoids, and inhibited the accumulation of malondialdehyde (MDA). Furthermore, MeJA delayed the ripening and senescence of the fruit by inhibiting the peel yellowing, flesh softening and change in soluble solids content (SSC) of mango fruit. The results indicated that the enhanced resistance of MeJA-treated mango to stem-end rot was potentially due to the activation of defense responses induced by synergistic interaction between JA and SA pathways, as well as delayed postharvest ripening. The MeJA treatment is a promising strategy to control stem-end rot of mango fruit.

Novel Insight into the Prevention and Therapeutic Treatment of Paulownia Witches’ Broom: A Study on the Effect of Salicylic Acid on Disease Control and the Changes in the Paulownia Transcriptome and Proteome

Paulownia species not only have significant economic benefits but also show great potential in ecological conservation. However, they are highly susceptible to phytoplasma infections, causing Paulownia witches’ broom (PaWB), which severely restricts the development of the Paulownia industry. Salicylic acid (SA) plays a crucial role in plant disease resistance. However, there have been no reports on the effect of SA on PaWB. Due to the properties of SA, it may have potential in controlling PaWB. Based on the above speculation, the prevention and therapeutic effect of SA on PaWB and its effect on the PaWB-infected Paulownia transcriptome and proteome were studied in this work. The results indicated that 0.1 mmol/L was the optimal SA concentration for inhibiting the germination of Paulownia axillary buds. In terms of resistance physiological indicators, SA treatment significantly affected both Paulownia tomentosa infected (PTI) seedlings and Paulownia fortunei infected (PFI) seedlings, where the activities of peroxidase (POD) and superoxide dismutase (SOD) were enhanced. Malondialdehyde (MDA), O2−, and H2O2, however, were significantly reduced. Specifically, after SA treatment, SOD activity increased by 28% in PFI and 25% in PTI, and POD activity significantly increased by 61% in PFI and 58% in PTI. Moreover, the MDA content decreased by 30% in PFI and 23% in PTI, the H2O2 content decreased by 26% in PFI and 19% in PTI, and the O2− content decreased by 21% in PFI and 19% in PTI. Transcriptomic analysis showed that there were significant upregulations of MYB, NAC, and bHLH and other transcription factors after SA treatment. Moreover, genes involved in PaWB-related defense responses such as RAX2 also showed significant differences. Furthermore, proteomic analysis indicated that after SA treatment, proteins involved in signal transduction, protein synthesis modification, and disease defense were differentially expressed. This work provides a research foundation for the prevention and treatment of PaWB and offers references for exploring anti-PaWB methods.

Effects of Ethylene Inhibitors on the Long-Term Maintenance of the Embryogenic Callus of Vitis vinifera L.

Vitis vinifera is an important fruit crop which is mainly consumed fresh or used for the production of wine. Genetic improvement programs through New Genomic Techniques (NGTs) aim to develop grapevine varieties resistant to biotic and abiotic stresses or enhancing nutraceutical properties. In order to apply NGTs, maintaining embryogenic calluses from flower tissues is critical. Optimizing culture conditions—pH, gelling agents, temperature, light, growth regulators, and gas composition—is essential for inducing efficient embryogenic responses tailored to each genotype/explant. Ethylene, a pivotal gaseous plant hormone, significantly influences tissue culture by affecting organogenesis and embryogenesis processes in several plants. Modulating ethylene levels shows promise for improving tissue culture vitality. This study evaluates in Vitis vinifera the effects of silver thiosulfate (STS) and salicylic acid (SA) on embryogenic callus growth, specifically investigating their roles in maintaining and inducing embryogenic competence. STS, particularly at 40 µM and 60 µM concentrations, effectively preserved embryogenic competence in Italia and Red Globe calluses, while high SA concentrations showed varied and occasionally adverse effects. At the same time, STS markedly suppressed the non-embryogenic callus growth in recalcitrant variety Italia, potentially increasing the ratio between embryogenic to non-embryogenic calluses development.

Transcriptomic and coexpression network analyses revealed the regulatory mechanism of Cydia pomonella infestation on the synthesis of phytohormones in walnut husks

The codling moth (Cydia pomonella) has a major effect on the quality and yield of walnut fruit. Plant defences respond to insect infestation by activating hormonal signalling and the flavonoid biosynthetic pathway. However, little is known about the role of walnut husk hormones and flavonoid biosynthesis in response to C. pomonella infestation. The phytohormone content assay revealed that the contents of salicylic acid (SA), abscisic acid (ABA), jasmonic acid (JA), jasmonic acid-isoleucine conjugate (JA-ILE), jasmonic acid-valine (JA-Val) and methyl jasmonate (MeJA) increased after feeding at different time points (0, 12, 24, 36, 48, and 72 h) of walnut husk. RNA-seq analysis of walnut husks following C. pomonella feeding revealed a temporal pattern in differentially expressed genes (DEGs), with the number increasing from 3,988 at 12 h to 5,929 at 72 h postfeeding compared with the control at 0 h postfeeding. Walnut husks exhibited significant upregulation of genes involved in various defence pathways, including flavonoid biosynthesis (PAL, CYP73A, 4CL, CHS, CHI, F3H, ANS, and LAR), SA (PAL), ABA (ZEP and ABA2), and JA (AOS, AOC, OPR, JAZ, and MYC2) pathways. Three gene coexpression networks that had a significant positive association with these hormonal changes were constructed based on the basis of weighted gene coexpression network analysis (WGCNA). We identified several hub transcription factors, including the turquoise module (AIL6, MYB4, PRE6, WRKY71, WRKY31, ERF003, and WRKY75), the green module (bHLH79, PCL1, APRR5, ABI5, and ILR3), and the magenta module (ERF27, bHLH35, bHLH18, TIFY5A, WRKY31, and MYB44). Taken together, these findings provide useful genetic resources for exploring the defence response mediated by phytohormones in walnut husks.

Response and disease resistance evaluation of sorghum seedlings under anthracnose stress

Sorghum is the world’s fifth-largest cereal crop, and anthracnose (Colletotrichum sublineola) is the main disease affecting sorghum. However, systematic research on the cellular structure, physiological and biochemical, and genes related to anthracnose resistance and disease resistance evaluation in sorghum is lacking in the field. Upon inoculation with anthracnose (C. sublineola) spores, disease-resistant sorghum (gz93) developed a relative lesion area (RLA) that was significantly smaller than that of the disease-susceptible sorghum (gz234). The leaf thickness, length and profile area of leaf mesophyll cells, upper and lower epidermal cells decreased in the lesion area, with a greater reduction observed in gz234 than in gz93. The damage caused by C. sublineola resulted in a greater decrease in the net photosynthetic rate (Pn) in gz234 than in gz93, with early-stage reduction due to stomatal limitation and late-stage reduction caused by lesions. Overall, the activities of superoxide dismutase (SOD) and catalase (CAT), the content of proline (Pro), abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA), and gibberellic acid (GA3), are higher in gz93 than in gz234 and may be positively correlated with disease resistance. While malondialdehyde (MDA) may be negatively correlated with disease resistance. Disease-resistant genes are significantly overexpressed in gz93, with significant expression changes in gz234, which is related to disease resistance in sorghum. Correlation analysis indicates that GA3, MDA, peroxidase (POD), and disease-resistance genes can serve as reference indicators for disease severity. The regression equation RLA = 0.029 + 8.02 × 10−6 JA–0.016 GA3 can predict and explain RLA. Principal component analysis (PCA), with the top 5 principal components for physiological and biochemical indicators and the top 2 principal components for disease-resistant genes, can explain 82.37% and 89.11% of their total variance, reducing the number of evaluation indicators. This study provides a basis for research on the mechanisms and breeding of sorghum with resistance to anthracnose.