Microneedle electrochemical sensor based on disposable stainless-steel wire for real-time analysis of indole-3-acetic acid and salicylic acid in tomato leaves infected by Pst DC3000 in situ.

BACKGROUND: Indole-3-acetic acid (IAA) and salicylic acid (SA), pivotal regulators in plant growth, are integral to a variety of plant physiological activities. The ongoing and simultaneous monitoring of these hormones in vivo enhances our comprehension of their interactive and regulatory roles. Traditional detection methods, such as liquid chromatography-mass spectrometry, cannot obtain precise and immediate information on IAA and SA due to the complexity of sample processing. In contrast, the electrochemical detection method offers high sensitivity, rapid response times, and compactness, making it well-suited for in vivo or real-time detection applications. RESULTS: A microneedle electrochemical sensor system crafted from disposable stainless steel (SS) wire was specifically designed for the real-time assessment of IAA and SA in plant in situ. This sensor system included a SS wire (100 µm diameter) coated with carbon cement and multi-walled carbon nanotubes, a plain platinum wire (100 µm diameter), and an Ag/AgCl wire (100 µm diameter). Differential pulse voltammetry and amperometry were adopted for detecting SA and IAA within the range of 0.1-20 µM, respectively. This sensor was applied to track IAA and SA fluctuations in tomato leaves during PstDC3000 infection, offering continuous data. Observations indicated an uptick in SA levels following infection, while IAA production was suppressed. The newly developed disposable SS wire-based microneedle electrochemical sensor system is economical, suitable for mass production, and inflicts minimal damage during the monitoring of SA and IAA in plant tissues. SIGNIFICANCE: This disposable microneedle electrochemical sensor facilitates in vivo detection of IAA and SA in smaller plant tissues and allows for long-time monitoring of their concentrations, which not only propels research into the regulatory and interaction mechanisms of IAA and SA but also furnishes essential tools for advancing precision agriculture.

A novel member of miR169 family negatively regulates maize resistance against Bipolaris maydis.

MicroRNAs (miRNAs) have been confirmed to play important roles in plant defense response. However, the key maize miRNAs involved in the defense response against Bipolaris maydis are very limited. In this study, a novel member of the miR169 family in response to B. maydis, named zma-miR169s, was discovered and investigated. The expression levels of pre-miR169s and zma-miR169s were significantly repressed during B. maydis infection. CRISPR/Cas9-induced zma-miR169s mutant exhibited more resistance against B. maydis, whereas overexpression zma-miR169s enhanced susceptibility, supporting that zma-miR169s might play a negative role in maize resistance. Moreover, RNA-seq and GO analysis showed that differentially expressed genes were highly enriched in the oxidation-reduction process and plant hormone pathway. Hence, reactive oxygen species (ROS) and plant hormone levels were further investigated. ROS detection confirmed that zma-miR169s mutant accumulated more ROS, while less ROS was detected in transgenic maize OE-miR169s. Furthermore, more remarkable changes in PR-1 expression levels and salicylic acid (SA) contents were detected in zma-miR169s mutant compared to wild-type and transgenic maize during B. maydis infection. Additionally, nuclear transcription factors (NF-YA1 and NF-YA13) were identified as targets regulated by zma-miR169s through the agrobacterium-mediated transient expression method. Overexpression of ZmNF-YA13 enhanced Arabidopsis resistance to Pseudomonas syringae pv. tomato DC3000. Taken together, our results suggest that zma-miR169s negatively regulate maize defense responses by influencing ROS accumulation and the SA-dependent signaling pathway.

Less Frequently Used Growth Regulators in Plant Tissue Culture.

Plant growth regulators are routinely added to in vitro culture media to foster the growth and differentiation of the cells, tissues, and organs. However, while the literature on usage of the more common auxins, cytokinins, gibberellins, abscisic acid, and ethylene is vast, other compounds that also have shown a growth-regulating activity have not been studied as frequently. Such substances are also capable of modulating the responses of plant cells and tissues in vitro by regulating their growth, differentiation, and regeneration competence, but also by enhancing their responses toward biotic and abiotic stress agents and improving the production of secondary metabolites of interest. This chapter will discuss the in vitro effects of several of such less frequently added plant growth regulators, including brassinosteroids (BRS), strigolactones (SLs), phytosulfokines (PSKs), methyl jasmonate, salicylic acid (SA), sodium nitroprusside (SNP), hydrogen sulfite, various plant growth retardants and inhibitors (e.g., ancymidol, uniconazole, flurprimidol, paclobutrazol), and polyamines.

Enhancement of cadmium uptake in Sedum alfredii through interactions between salicylic acid/jasmonic acid and rhizosphere microbial communities.

The focus on phytoremediation in soil cadmium (Cd) remediation is driven by its cost-effectiveness and eco-friendliness. Selecting suitable hyperaccumulators and optimizing their growth conditions are key to enhance the efficiency of heavy metal absorption and accumulation. Our research has concentrated on the role of salicylic acid (SA) and jasmonic acid (JA) in facilitating Cd phytoextraction by "Sedum alfredii (S. alfredii)" through improved soil-microbe interactions. Results showed that SA or JA significantly boosted the growth, stress resistance, and Cd extraction efficiency in S. alfredii. Moreover, these phytohormones enhanced the chemical and biochemical attributes of the rhizosphere soil, such as pH and enzyme activity, affecting soil-root interactions. High-throughput sequencing analysis has shown that Patescibacteria and Umbelopsis enhanced S. alfredii's growth and Cd extraction by modifying the bioavailability and the chemical conditions of Cd in soil. Structural Equation Model analysis further verified that phytohormones significantly enhanced the interaction between S. alfredii, soil, and microbes, leading to a marked increase in Cd accumulation in the plant. These discoveries emphasized the pivotal role of phytohormones in modulating the hyperaccumulators' response to environmental stress and offered significant scientific support for further enhancing the potential of hyperaccumulators in ecological restoration technologies using phytohormones.

Salicylic acid modulates secondary metabolism and enhanced colchicine accumulation in long yellow daylily (Hemerocallis citrina).

Salicylic acid (SA) is an essential phytoregulator that is widely used to promote the synthesis of high-value nutraceuticals in plants. However, its application in daylily, an ornamental plant highly valued in traditional Chinese medicine, has not been reported. Herein, we investigated the exogenous SA-induced physiological, transcriptional and biochemical changes in long yellow daylily (LYD). We found that 2 mg/L foliar SA treatment significantly improved LYD plant growth and yield. Transcriptome sequencing and differentially expressed genes (DEGs) analysis revealed that the phenylpropanoid biosynthesis, isoquinoline alkaloid biosynthesis, sulfur metabolism, plant hormone signal transduction and tyrosine metabolism were significantly induced in SA-treated leaves. Many transcription factors and antioxidant system-related DEGs were induced under the SA treatment. Biochemical analyses showed that the leaf contents of soluble sugar, soluble protein (Cpr), ascorbic acid (AsA) and colchicine were significantly increased by 15.15% (from 30.16 ±â€…1.301 to 34.73 ±â€…0.861 mg/g), 19.54% (from 60.3 ±â€…2.227 to 72.08 ±â€…1.617 mg/g), 30.45% (from 190.1 ±â€…4.56 to 247.98 ±â€…11.652 µg/g) and 73.05% (from 3.08 ±â€…0.157 to 5.33 ±â€…0.462 µg/g), respectively, under the SA treatment. Furthermore, we identified 15 potential candidate genes for enhancing the growth, production and phytochemical content of LYD. Our results provide support for the bioaccumulation of colchicine in yellow daylily and valuable resources for biotechnological-assisted production of this important nutraceutical in Hemerocallis spp.

Arsenic transport, detoxification, and recent technologies for mitigation: A systemic review.

Arsenic (As) is an acute toxic metalloid that affects plant growth and development. As is found in the environment in organic and inorganic forms, but arsenite As(III) and arsenate As(V) are the most prevalent forms that negatively impact the plants. Roots exposed to As can easily absorb it mainly through transporters that carry vital mineral nutrients. As reach the food chain via crops irrigated with As-polluted water and exerts a negative impact. Even at low levels, As exposure disrupts the regular functioning of plants by generating a high level of reactive oxygen species (ROS) results into oxidative damage, and disruption of redox system. Plants have built-in defence mechanisms to combat this oxidative damage. The development of a food crop with lower As levels is dependent upon understanding the molecular process of As detoxification in plants, which will help reduce the consumption of As-contaminated food. Numerous genes in plants that may provide tolerance under hazardous conditions have been examined using genetic engineering techniques. The suppression of genes by RNA interference (RNAi) and CRISPR-Cas 9 (CRISPR associated protein 9) technology revealed an intriguing approach for developing a crop that has minimal As levels in consumable portions. This study aims to present current information on the biochemical and molecular networks associated with As uptake, as well as recent advances in the field of As mitigation using exogenous salicylic acid (SA), Serendipita indica and biotechnological tools in terms of generating As-tolerant plants with low As accumulation.

Salicylic Acid Priming Improves Cotton Seedling Heat Tolerance through Photosynthetic Pigment Preservation, Enhanced Antioxidant Activity, and Osmoprotectant Levels.

The escalating global temperatures associated with climate change are detrimental to plant growth and development, leading to significant reductions in crop yields worldwide. Our research demonstrates that salicylic acid (SA), a phytohormone known for its growth-promoting properties, is crucial in enhancing heat tolerance in cotton (Gossypium hirsutum). This enhancement is achieved through modifications in various biochemical, physiological, and growth parameters. Under heat stress, cotton plants typically show significant growth disturbances, including leaf wilting, stunted growth, and reduced biomass. However, priming cotton plants with 1 mM SA significantly mitigated these adverse effects, evidenced by increases in shoot dry mass, leaf-water content, and chlorophyll concentrations in the heat-stressed plants. Heat stress also prompted an increase in hydrogen peroxide levels-a key reactive oxygen species-resulting in heightened electrolyte leakage and elevated malondialdehyde concentrations, which indicate severe impacts on cellular membrane integrity and oxidative stress. Remarkably, SA treatment significantly reduced these oxidative stresses by enhancing the activities of critical antioxidant enzymes, such as catalase, glutathione S-transferase, and ascorbate peroxidase. Additionally, the elevated levels of total soluble sugars in SA-treated plants enhanced osmotic regulation under heat stress. Overall, our findings reveal that SA-triggered protective mechanisms not only preserve photosynthetic pigments but also ameliorate oxidative stress and boost plant resilience in the face of elevated temperatures. In conclusion, the application of 1 mM SA is highly effective in enhancing heat tolerance in cotton and is recommended for field trials before being commercially used to improve crop resilience under increasing global temperatures.

Salicylic Acid Is Involved in the Growth Inhibition Caused by Excessive Ammonium in Oilseed Rape (Brassica napus L.).

Rapeseed (Brassica napus L.) is extremely sensitive to excessive NH4+ toxicity. There remains incomplete knowledge of the causal factors behind the growth suppression in NH4+-nourished plants, with limited studies conducted specifically on field crop plants. In this study, we found that NH4+ toxicity significantly increased salicylic acid (SA) accumulation by accelerating the conversion of SA precursors. Moreover, exogenous SA application significantly aggravated NH4+ toxicity symptoms in the rapeseed shoots. Genome-wide differential transcriptomic analysis showed that NH4+ toxicity increased the expression of genes involved in the biosynthesis, transport, signaling transduction, and conversion of SA. SA treatment significantly increased shoot NH4+ concentrations by reducing the activities of glutamine synthase and glutamate synthase in NH4+-treated rapeseed plants. The application of an SA biosynthesis inhibitor, ABT, alleviated NH4+ toxicity symptoms. Furthermore, SA induced putrescine (Put) accumulation, resulting in an elevated ratio of Put to [spermidine (Spd) + spermine (Spm)] in the NH4+-treated plants, while the opposite was true for ABT. The application of exogenous Put and its biosynthesis inhibitor DFMA induced opposite effects on NH4+ toxicity in rapeseed shoots. These results indicated that the increased endogenous SA contributed noticeably to the toxicity caused by the sole NH4+-N supply in rapeseed shoots. This study provided fresh perspectives on the mechanism underlying excessive NH4+-induced toxicity and the corresponding alleviating strategies in plants.

LW-1 induced resistance to TMV in tobacco was mediated by nitric oxide and salicylic acid pathway.

The objective of this study was to investigate the mechanism underlying LW-1-induced resistance to TMV in wild-type and salicylic acid (SA)-deficient NahG transgenic tobacco plants. Our findings revealed that LW-1 failed to induce antivirus infection activity and increase SA content in NahG tobacco, indicating the crucial role of SA in these processes. Meanwhile, LW-1 triggered defense-related early-signaling nitric oxide (NO) generation, as evidenced by the emergence of NO fluorescence in both types of tobacco upon treatment with LW-1, however, NO fluorescence was stronger in NahG compared to wild-type tobacco. Notably, both of them were eliminated by the NO scavenger cPTIO, which also reversed LW-1-induced antivirus activity and the increase of SA content, suggesting that NO participates in LW-1-induced resistance to TMV, and may act upstream of the SA pathway. Defense-related enzymes and genes were detected in tobacco with or without TMV inoculation, and the results showed that LW-1 regulated both enzyme activity (ß-1,3-glucanase [GLU], catalase [CAT] and phenylalanine ammonia-lyase [PAL]) and gene expression (PR1, PAL, WYKY4) through NO signaling in both SA-dependent and SA-independent pathways.

Expression pattern of the poplar GSTU family members in response to Alternaria alternate and PdbGSTU10 confers A. alternate resistance to Populus davidiana × P. bolleana.

Plant tau glutathione S-transferase (GSTU) is a kind of multiple functions enzyme, but its specific roles in poplar disease resistance remain uncertain. In this study, 27 PdbGSTU-encoding genes from Populus davidiana × P. bollena were cloned and their protein architectures and phylogenetic relationships were subsequently analyzed. Expression analysis revealed that PdbGSTUs were differentially expressed under Alternaria alternate infection. Then, the PdbGSTU10 was further induced by phytohormones and H2O2, especially salicylic acid (SA), indicating its potential role in the pathogen defense of poplar. Subsequently, gain- and loss-of-function assays showed that overexpressed PdbGSTU10 activated antioxidant enzymes and significantly decreased reactive oxygen species (ROS) content, ultimately improving the resistance to A. alternate in poplar. Conversely, silencing PdbGSTU10 had the opposite effect. Moreover, overexpressed PdbGSTU10 also increased the content of SA and induced the expression of SA signal-related genes. These results showed that PdbGSTU10 may enhance disease resistance in poplar by scavenging ROS and affecting the SA signaling pathway. Our findings contribute to the understanding of the functions of GSTU in woody plants, particularly in disease resistance.

Functional Analysis of Type III Effectors in Xanthomonas campestris pv. campestris Reveals Distinct Roles in Modulating Arabidopsis Innate Immunity.

Xanthomonas campestris pv. campestris (Xcc) is a significant phytopathogen causing black rot disease in crucifers. Its virulence relies heavily on the type III secretion system (T3SS), facilitating effector translocation into plant cells. The type III effectors (T3Es) disrupt cellular processes, promoting pathogen proliferation. However, only a few T3Es from Xcc have been thoroughly characterized. In this study, we further investigated two effectors using the T3Es-deficient mutant and the Arabidopsis protoplast system. XopE2Xcc triggers Arabidopsis immune responses via an unidentified activator of the salicylic acid (SA) signaling pathway, whereas XopLXcc suppresses the expression of genes associated with patterns-triggered immunity (PTI) and the SA signaling pathway. These two effectors exert opposing effects on Arabidopsis immune responses. Additionally, we examined the relationship between the specific domains and functions of these two effector proteins. Our findings demonstrate that the N-myristoylation motif and N-terminal domain are essential for the subcellular localization and virulence of XopE2Xcc and XopLXcc, respectively. These novel insights enhance our understanding of the pathogenic mechanisms of T3Es and contribute to developing effective strategies for controlling bacterial disease.

Alleviating salinity stress in canola (Brassica napus L.) through exogenous application of salicylic acid.

Canola, a vital oilseed crop, is grown globally for food and biodiesel. With the enormous demand for growing various crops, the utilization of agriculturally marginal lands is emerging as an attractive alternative, including brackish-saline transitional lands. Salinity is a major abiotic stress limiting growth and productivity of most crops, and causing food insecurity. Salicylic acid (SA), a small-molecule phenolic compound, is an essential plant defense phytohormone that promotes immunity against pathogens. Recently, several studies have reported that SA was able to improve plant resilience to withstand high salinity. For this purpose, a pot experiment was carried out to ameliorate the negative effects of sodium chloride (NaCl) on canola plants through foliar application of SA. Two canola varieties Faisal (V1) and Super (V2) were assessed for their growth performance during exposure to high salinity i.e. 0 mM NaCl (control) and 200 mM NaCl. Three levels of SA (0, 10, and 20 mM) were applied through foliar spray. The experimental design used for this study was completely randomized design (CRD) with three replicates. The salt stress reduced the shoot and root fresh weights up to 50.3% and 47% respectively. In addition, foliar chlorophyll a and b contents decreased up to 61-65%. Meanwhile, SA treatment diminished the negative effects of salinity and enhanced the shoot fresh weight (49.5%), root dry weight (70%), chl. a (36%) and chl. b (67%). Plants treated with SA showed an increased levels of both enzymatic i.e. (superoxide dismutase (27%), peroxidase (16%) and catalase (34%)) and non-enzymatic antioxidants i.e. total soluble protein (20%), total soluble sugar (17%), total phenolic (22%) flavonoids (19%), anthocyanin (23%), and endogenous ascorbic acid (23%). Application of SA also increased the levels of osmolytes i.e. glycine betaine (31%) and total free proline (24%). Salinity increased the concentration of Na+ ions and concomitantly decreased the K+ and Ca2+ absorption in canola plants. Overall, the foliar treatments of SA were quite effective in reducing the negative effects of salinity. By comparing both varieties of canola, it was observed that variety V2 (Super) grew better than variety V1 (Faisal). Interestingly, 20 mM foliar application of SA proved to be effective in ameliorating the negative effects of high salinity in canola plants.

Exploring lipid signaling in plant physiology: From cellular membranes to environmental adaptation.

Lipids have evolved as versatile signaling molecules that regulate a variety of physiological processes in plants. Convincing evidence highlights their critical role as mediators in a wide range of plant processes required for survival, growth, development, and responses to environmental conditions such as water availability, temperature changes, salt, pests, and diseases. Understanding lipid signaling as a critical process has helped us expand our understanding of plant biology by explaining how plants sense and respond to environmental cues. Lipid signaling pathways constitute a complex network of lipids, enzymes, and receptors that coordinate important cellular responses and stressing plant biology's changing and adaptable traits. Plant lipid signaling involves a wide range of lipid classes, including phospholipids, sphingolipids, oxylipins, and sterols, each of which contributes differently to cellular communication and control. These lipids function not only as structural components, but also as bioactive molecules that transfer signals. The mechanisms entail the production of lipid mediators and their detection by particular receptors, which frequently trigger downstream cascades that affect gene expression, cellular functions, and overall plant growth. This review looks into lipid signaling in plant physiology, giving an in-depth look and emphasizing its critical function as a master regulator of vital activities.

Laser-disintegrated copper-activated salicylic acid (Cu-SA) nanoparticles suppressed the seed-borne pathogens of rice with enhanced seed invigoration parameters.

Leading phytopathological research is focused on managing seed-borne pathogens of rice through the utilization of engineered nanomaterials. Herein, blue laser-induced topo-morphologically nano-advanced copper salicylates (Cu-SA) (Cu/SA in 1:1 and 1:2 ratio) were prepared and evaluated for their augmented antifungal potential along seed invigoration effects in contrast to their prepared sonicated formulations. Laser disintegration on the Cu-SA (Cu/SA in 1:1 and 1:2 ratio) was achieved with high degree of success and precision using blue laser, which yielded uniformly distributed spherical nanoparticles with a narrow size distribution and better crystallinity than aqua-dispersed sonicated formulations. In vitro antifungal evaluation against seed-borne fungi of rice viz. Fusarium verticillioides and Fusarium fujikuroi revealed multiple times the augmented potential of laser-disintegrated nanoformulations (l-CuSA) than sonicated (s-CuSA) and bulk samples. Laser-induced nano-sodium bis(2-oxobenzoato)cuprate (II) (l-CuSA2) with Cu/SA in 1:2 ratio was the best to inhibit the in vitro fungal growth. Ultra-micrographs and fungal double-staining assay further rationalized the membrane disruption as the mode of action for the fungitoxicity. Nanopriming of fungal infested rice seeds with l-CuSA2 at 2500 µg/mL for 8 h showed the maximum reduction of seed rot (80.43%) and seedling blight (63.15%) with respect to control (untreated). The seed-invigorating factors of l-CuSA2 nanoprimed seeds were enhanced to maximum extent and showed the highest per cent germination (35.29%), shoot length (11.42%), root length (21.14%), dry weight (75.43%) and vigour index (81.04%) over the control. Inclusively, the seed nanopriming with l-CuSA2 proved as agro-compatible hypo-toxic semi natural nanoplatform for sustainable agriculture.

Chloride salt enhances plant resistance to biotic stresses.

Biotic stresses caused by bacterial and fungal pathogens damage crops; identifying treatments that enhance disease resistance provides important information for understanding plant defenses and sustainable agriculture. Salt stress affects crop yields worldwide; however, studies have focused on the toxic sodium ion, leaving the effects of the chloride ion unclear. In this study, we found that irrigation with a combination of chloride salts (MgCl2, CaCl2, and KCl) suppressed the cell death phenotype of the ceramide kinase mutant acd5. Chloride salt pre-irrigation also significantly limited the cell death caused by Pseudomonas syringae pv maculicola infection and inhibited the multiplication of this bacterial pathogen in a mechanism partially dependent on the salicylic acid pathway. Moreover, chloride salt pre-irrigation improved plant defenses against the fungal pathogen challenge, confining the lesion area caused by Botrytis cinerea infection. Furthermore, the growth of herbivorous larvae of Spodoptera exigua was retarded by feeding on chloride salt irrigated plants. Thus, our data suggest that treatment with Cl- increases broad spectrum resistance to biotic challenges.

The genetic orchestra of salicylic acid in plant resilience to climate change induced abiotic stress: critical review.

Climate change, driven by human activities and natural processes, has led to critical alterations in varying patterns during cropping seasons and is a vital threat to global food security. The climate change impose several abiotic stresses on crop production systems. These abiotic stresses include extreme temperatures, drought, and salinity, which expose agricultural fields to more vulnerable conditions and lead to substantial crop yield and quality losses. Plant hormones, especially salicylic acid (SA), has crucial roles for plant resiliency under unfavorable environments. This review explores the genetics and molecular mechanisms underlying SA's role in mitigating abiotic stress-induced damage in plants. It also explores the SA biosynthesis pathways, and highlights the regulation of their products under several abiotic stresses. Various roles and possible modes of action of SA in mitigating abiotic stresses are discussed, along with unraveling the genetic mechanisms and genes involved in responses under stress conditions. Additionally, this review investigates molecular pathways and mechanisms through which SA exerts its protective effects, such as redox signaling, cross-talks with other plant hormones, and mitogen-activated protein kinase pathways. Moreover, the review discusses potentials of using genetic engineering approaches, such as CRISPR technology, for deciphering the roles of SA in enhancing plant resilience to climate change related abiotic stresses. This comprehensive analysis bridges the gap between genetics of SA role in response to climate change related stressors. Overall goal is to highlight SA's significance in safeguarding plants and by offering insights of SA hormone for sustainable agriculture under challenging environmental conditions.

Contribution of Antioxidant System Components to the Long-Term Physiological and Protective Effect of Salicylic Acid on Wheat under Salinity Conditions.

Salicylic acid (SA) plays a crucial role in regulating plant growth and development and mitigating the negative effects of various stresses, including salinity. In this study, the effect of 50 µM SA on the physiological and biochemical parameters of wheat plants under normal and stress conditions was investigated. The results showed that on the 28th day of the growing season, SA pretreatment continued to stimulate the growth of wheat plants. This was evident through an increase in shoot length and leaf area, with the regulation of leaf blade width playing a significant role in this effect. Additionally, SA improved photosynthesis by increasing the content of chlorophyll a (Chl a) and carotenoids (Car), resulting in an increased TAP (total amount of pigments) index in the leaves. Furthermore, SA treatment led to a balanced increase in the levels of reduced glutathione (GSH) and oxidized glutathione (GSSG) in the leaves, accompanied by a slight but significant accumulation of ascorbic acid (ASA), hydrogen peroxide (H2O2), proline, and the activation of glutathione reductase (GR) and ascorbate peroxidase (APX). Exposure to salt stress for 28 days resulted in a reduction in length and leaf area, photosynthetic pigments, and GSH and ASA content in wheat leaves. It also led to the accumulation of H2O2 and proline and significant activation of GR and APX. However, SA pretreatment exhibited a long-term growth-stimulating and protective effect under stress conditions. It significantly mitigated the negative impacts of salinity on leaf area, photosynthetic pigments, proline accumulation, lipid peroxidation, and H2O2. Furthermore, SA reduced the salinity-induced depletion of GSH and ASA levels, which was associated with the modulation of GR and APX activities. In small-scale field experiments conducted under natural growing conditions, pre-sowing seed treatment with 50 µM SA improved the main indicators of grain yield and increased the content of essential amino acids in wheat grains. Thus, SA pretreatment can be considered an effective approach for providing prolonged protection to wheat plants under salinity and improving grain yield and quality.

Effect of Chitosan/Gum Arabic Blends Enriched by Sodium Nitroprusside or Methyl Salicylate on the Storability and Antioxidant Activity of Tomato Fruit.

The impact of methyl salicylate (MeSA) or sodium nitroprusside (SNP) in chitosan (CS)/Gum Arabic (GA) mixture on physio-chemical characteristics and antioxidant status during the postharvest ripening of green tomato fruits was studied. CS/GA-MeSA at a 1 mM formulation was the best treatment to retard firmness and titratable acidity (TA) losses. Moreover, this formulation retarded pigmentation progress where it had the lowest significant values of total carotenes (TCs) and lycopene (LYP) contents until the 15th day of the storage period, as well as efficiently faced the rise in malondialdehyde (MDA) levels. Moreover, peroxidase (POD), polyphenol oxidase (PPO), catalase (CAT), and phenylalanine ammonia-lyase (PAL) activities of tomatoes treated with CS/GA-SNP at 2 mM were significantly better than that of control in the primary stages of storage. CS/GA-SNP at a 2 mM formulation showed an extremely high significant content of total polyphenol (TP) in the early stage of storage, while CS/GA and CS/GA-MeSA at 1 and 2 mM accumulated higher significant TP contents than uncoated fruits at the late stage of storage. All formulations were characterized by FTIR spectroscopy. Furthermore, the polymer formulations exhibited strong antifungal activity against Alternaria alternata and Botrytis cinerea as major pathogens of postharvest tomatoes. Transmission electron microscope (TEM) observations for the mycelia of both fungi treated by CS/GA-MeSA at 2 mM revealed serious ultrastructural damage, including distortion of the cell wall and cell membrane and degradation of cytoplasmic organelles.

The miR7125-MdARF1 module enhances the resistance of apple to Colletotrichum gloeosporioides by promoting lignin synthesis in response to salicylic acid signalling.

Apple is an important cash crop in China, and it is susceptible to fungal infections that have deleterious effects on its yield. Apple bitter rot caused by Colletorichum gloeosporioides is one of the most severe fungal diseases of apple. Salicylic acid (SA) is a key signalling molecule in the plant disease resistance signalling pathways. Lignin synthesis also plays a key role in conferring disease resistance. However, few studies have clarified the relationship between the SA disease resistance signalling pathway and the lignin disease resistance pathway in apple. MdMYB46 has previously been shown to promote lignin accumulation in apple and enhance salt and osmotic stress tolerance. Here, we investigated the relationship between MdMYB46 and biological stress; we found that MdMYB46 overexpression enhances the resistance of apple to C. gloeosporioides. We also identified MdARF1, a transcription factor upstream of MdMYB46, via yeast library screening and determined that MdARF1 was regulated by miR7125 through psRNATarget prediction. This regulatory relationship was confirmed through LUC and qRT-PCR experiments, demonstrating that miR7125 negatively regulates MdARF1. Analysis of the miR7125 promoter revealed that miR7125 responds to SA signals. The accumulation of SA level will result in the decrease of miR7125 expression level. In sum, the results of our study provide novel insights into the molecular mechanisms underlying the resistance of apple to C. gloeosporioides and reveal a new pathway that enhances lignin accumulation in apple in response to SA signals. These findings provide valuable information for future studies aimed at breeding apple for disease resistance.

Exploring bioluminescence in Aglaonema: Investigating Vibrio campbellii translocation and plant responses under CaCl2 stimulation.

The feasibility of creating light-emitting plants by immobilizing Vibrio campbellii RMT1 on the rhizospheric zone of Aglaonema sp. 'Banlangngoen' was investigated in depth, including bacteria translocation and plant response. Results from scanning electron microscope showed that an inorganic salt-containing medium affected the root. However, transmission electron microscope results displayed bacteria translocation through the root to the leaf and colonized in the cytosol of vascular tissues. Bacteria cell counts exhibited high colonization in the root zone, approximately 3.65 × 106 CFU/mL, resulting in a light-emitting intensity increase of 23.68-fold higher than the control after the first week. Nevertheless, light microscope revealed that inorganic salts in the culture medium led to enlarged air spaces, resulting in leaf and stalk withering. Notably, spraying plants with calcium chloride (CaCl2) solution effectively mitigated salt stress, activated luminescence, and facilitated bacterial movement from roots to leaves. Additionally, CaCl2 contributed to ongoing salinity reduction in the culture medium, as evidenced by reduced malondialdehyde levels, alongside increased indole-3-acetic acid and salicylic acid concentrations, indicating plant defense responses. The interaction between plants and luminescent bacteria demonstrated the potential for producing glowing plants following CaCl2 application, addressing salinity stress, enhancing luminescence, and maintaining plant growth.