Response of Phenylpropanoid Pathway and the Role of Polyphenols in Plants under Abiotic Stress

5-Azacytidine accelerates mandarin fruit post-ripening and enhances lignin-based pathogen defense through remarkable gene expression activation

5-Azacytidine (AZ) is a DNA methylation inhibitor that has recently demonstrated potential in regulating fruit quality through exogenous application. In this study, we treated mandarin fruits for 4-day storage. Noteworthy were the induced degreening and the enhanced citrus aroma of fruits under AZ treatment, involving the promotion of chlorophyll degradation, carotenoid biosynthesis, and limonene biosynthesis. Key genes associated with these processes exhibited expression level increases of up to 123.8 times. Additionally, AZ treatment activated defense-related enzymes and altered phenylpropanoid carbon allocation towards lignin biosynthesis instead of flavonoid biosynthesis. The expression levels of lignin biosynthesis-related genes increased by nearly 100 times, leading to fortified lignin that is crucial for citrus defense against Penicillium italicum. Currently, the underlying mechanisms of such intense AZ-induced changes in gene expressions remain unclear and further research could help establish AZ treatment as a viable strategy for citrus preservation.

Dielectric Barrier Discharge Cold Plasma Improves Storage Stability in Paddy Rice by Activating the Phenylpropanoid Biosynthesis Pathway

A nonthermal pretreatment using dielectric barrier discharge cold plasma (DBD-CP) was developed to improve the stress resistance of paddy rice during postharvest storage. The physicochemical properties, bioactive characteristics, and secondary metabolites of paddy rice were assessed after applying an optimized DBD-CP procedure, with enzyme activities and gene expression monitored over a 60 day storage period at 35 °C. A 17.06% reduction in the total color change index was noted in the DBD-CP group. Bioactive compounds, particularly gallic acid, were significantly increased, enhancing the defense mechanisms against high-temperature stress. Nontargeted metabolomics analysis indicated an upregulation of phenylpropanoid metabolism in DBD-CP-treated rice compared to controls, with notable increases in secondary metabolites such as coumaric acid, caffeic acid, and sinapic acid, suggesting potential biomarkers for stress resistance. Further verification showed significant enhancements in key enzymes of phenylpropanoid metabolism, including phenylalanine ammonia lyase (PAL), cinnamic acid-4-hydroxylase (C4H), plant coumaric acid-3-hydroxylase (C3H), and cinnamyl alcohol dehydrogenase (CAD), with increases ranging from 1.71 to 2.28 times. Gene expression levels of OsPAL7, OsC4H4, and OsCAD2 aligned with these enzymatic changes post-DBD-CP treatment. In conclusion, DBD-CP treatment can modulate phenylpropanoid metabolism in paddy rice, thereby enhancing bioactive compound levels to reduce stress damage during high-temperature storage.

Xyloglucan endotransglucosylase-hydrolase 1 is a negative regulator of drought tolerance in barley via modulating lignin biosynthesis and stomatal closure

The projected increase in drought severity and duration worldwide poses a significant threat to crop growth and sustainable food production. Xyloglucan endotransglucosylase/hydrolases (XTHs) family is essential in cell wall modification through the construction and restructuring of xyloglucan cross-links, but their role in drought tolerance and stomatal regulation is still illusive. We cloned and functionally characterized HvXTH1 using genetic, physiological, biochemical, transcriptomic and metabolomic approaches in barley. Evolutionary bioinformatics showed that orthologues of XTH1 was originated from Streptophyte algae (e.g. some species in the Zygnematales) the closest clade to land plants based on OneKP database. HvXTH1 is highly expressed in leaves and HvXTH1 is localized to the plasma membrane. Under drought conditions, silencing HvXTH1 in drought-tolerant Tibetan wild barley XZ5 induced a significant reduction in water loss rate and increase in biomass, however overexpressing HvXTH1 exhibited drought sensitivity with significantly less drought-responsive stomata, lower lignin content and a thicker cell wall. Transcriptome profile of the wild type Golden Promise and HvXTH1-OX demonstrated that drought-induced differentially expressed genes in leaves are related to cell wall biosynthesis, abscisic acid and stomatal signaling, and stress response. Furthermore, overexpressing HvXTH1 suppressed both genes and metabolites in the phenylpropanoid pathway for lignin biosynthesis, leading to drought sensitivity of HvXTH1-OX. We provide new insight by deciphering the function of a novel protein HvXTH1 for drought tolerance in cell wall modification, stomatal regulation, and phenylpropanoid pathway for lignin biosynthesis in barley. The function of HvXTH1 in drought response will be beneficial to develop crop varieties adapted to drought.

Transcription factor NtMYB59 targets NtMYB12 to negatively regulate the biosynthesis of polyphenols in Nicotiana tabacum

MYB12 is a key regulator that has been shown to promote the accumulation of various phenylpropanoid compounds in plants. However, the regulation of MYB12 gene is largely unknown. In this study, we found that overexpression of the NtMYB59 gene significantly inhibited the accumulation of chlorogenic acid (CGA), flavonols, and anthocyanins in tobacco, while knock-down and knock-out of NtMYB59 significantly increased the contents of these polyphenol compounds. Transcriptome analysis between WT and NtMYB59-OE plants revealed several differentially expressed genes (DEGs) encoding crucial enzymes in the phenylpropanoid pathway and the transcription factor NtMYB12. ChIP-seq assay further indicated that NtMYB12 might be a direct target of NtMYB59. Subsequent yeast one-hybrid, electrophoretic mobility shift assay, and Dual-Luciferase assays confirmed that NtMYB59 directly binds to the promoter of NtMYB12 to inhibit its expression. Moreover, loss-function of NtMYB59 significantly promoted the accumulation of flavonols and anthocyanins in ntmyb59, but their contents in ntmyb59/ntmyb12 double mutants were significantly lower than that of WT and ntmyb59 plants, indicating that the regulation of NtMYB59 on flavonoids biosynthesis depends on the activity of NtMYB12. Our study revealed that NtMYB59 regulates the expression of NtMYB12, and provided new potential strategies for modulating phenylpropanoids biosynthesis in tobacco.

Regulatory effect of pipecolic acid (Pip) on the antioxidant system activity of Mesembryanthemum crystallinum plants exposed to bacterial treatment

The presented study aims to elucidate the regulatory role of Pipecolic acid (Pip) in modulating the antioxidant system activity of Mesembryanthemum crystallinum plants exposed to Pseudomonas syringae infestation. M. crystallinum, known for its semi-halophytic nature, can transition its metabolism from C3 to CAM under salt stress conditions. The research encompasses the antioxidant system of the plants, covering both enzymatic and low molecular weight components. The findings indicate that Pip supplementation confers a beneficial effect on certain elements of the antioxidant system when the plants are subjected to stress induced by bacteria. Notably, during critical periods, particularly in the initial days post-bacterial treatment, M. crystallinum plants supplemented with Pip and exhibiting C3 metabolism display heightened total antioxidant capacity. This enhancement includes increased superoxide dismutase activity and elevated levels of glutathione and proline. However, in plants with salinity-induced CAM, where these parameters are naturally higher, the supplementation of Pip does not yield significant effects. These results validate the hypothesis that the regulatory influence of Pip on defence mechanisms against biotic stress is contingent upon the metabolic state of the plant. Furthermore, this regulatory effect is more pronounced in C3 plants of M. crystallinum than those undergoing CAM metabolism induced by salinity stress.

Flaxseed polyphenols: Effects of varieties on its composition and antioxidant capacity

This study identified phenolic compounds in five flaxseed varieties and evaluated their antioxidant activities. Results showed significant variations in phenolic acids and flavonoids among the varieties. Longya 16 had the lowest flavonoid content, Longya 13 had the lowest phenolic acid content, while Longya 10 exhibited the highest content and diversity of polyphenols, including six flavonoids (vitexin, quercitrin, quercetin, apigenin, kaempfero1, (+)-dihydroquercetin) and five phenolic acids (gallic acid, vanillic acid, ferulic acid, sinapic acid, and 4-hydroxybenzoic acid). Antioxidant activity was assessed using DPPH and ABTS radical scavenging assays, and cell-based assays under tBHP-induced oxidative stress. Flaxseed polyphenol extracts significantly reduced ROS, MDA, and GSSG levels and increased SOD and CAT activities, preserving cell vitality and morphology. These findings confirmed the significant antioxidant activity of flaxseed polyphenols, providing a theoretical basis for their application in antioxidative functional areas.

Biochemical and morpho-physiological insights revealed low moisture stress adaptation mechanisms in cotton (Gossypium hirsutum L.)

Cotton (Gossypium hirsutum L.) is a multipurpose crop. Abiotic stresses, especially extreme heat and drought, limit crop growth and thus reduce cotton yield by about 50%. In this study, 30 cotton genotypes were tested against low moisture stress in a pot experiment in triplicates along with control under wire house conditions. At the 3-4 leaf stage, different morpho-physiological and biochemical parameters were measured in order to select the low moisture stress-tolerant genotypes. For the selection of the best performing genotypes, Multi-Trait Genotype-Ideotype Distance Index (MGIDI) was used for the ranking of genotypes on the basis of multiple indices. For biochemical traits, 09 (TPC, TF, TSP, MDA, SOD, POD, CAT, APX, and Proline) out of 24 showed significant genotypic effects and were used for MGIDI. Eight genotypes (N-812 N-1296 N-696 N-377 N-121-896 N-T86, and N-3496) were observed to be best performing than others at 25% selection pressure (SI = 25%). For morpho-physiological traits, 14 out of 15 showed significant genotypic effects and used for MGIDI. Ten genotypes (N-1237 N-812 N-1296 N-696 N-9078 N-377 N-512 N-121 N-375, and N-896) were observed to be best performing at 35% selection pressure (SI = 35%). Six genotypes, i.e. N-812-1296 N-696 N-377 N-121, and N-896 were found common in both MGIDI analysis. In conclusion, three genotypes, i.e. N-696, N-896, and N-T86 proved to be most resilient to low moisture stress. Develop protocols, identified genotypes and markers that can be used for development of climate-smart cotton genotypes.

Seasonal influence on tomato fruit metabolome profile: Implications for ABA signaling in multi-stress resilience

The increasing effects of climate change are leading to an increase in the number and intensity of extreme events, making it essential to study how plants respond to various stresses occurring simultaneously. A crucial regulator of plant responses to abiotic stress is abscisic acid (ABA), as its accumulation in response to stress leads to transcriptomic and metabolomic changes that contribute to plant stress tolerance. In the present study, we investigated how ABA, stress conditions (salinity, water deficit and their combination) and seasons (autumn-winter and spring-summer) regulate tomato fruit yield and metabolism using tomato wild type (WT) and the ABA-deficient flacca mutant (flc) under stress conditions in cold and warm seasons. Our results showed that the applied stresses did not have the same effect in the warm season as in the cold season. In WT plants, the levels of other flavonoids, lignans and other polyphenols were higher in summer fruits, whereas the levels of anthocyanins, flavanols, flavonols, phenolic acids and stilbenes were higher in winter fruits. Furthermore, the significant increase in anthocyanins and flavonols was associated with the combination of salinity + water deficit in both seasons. Additionally, under certain conditions, flc mutants showed an enrichment of the superclasses of benzenoids and organosulphur compounds. The synthesis of phenolic compounds in flc fruits was also significantly different compared to WT plants. Thus, the metabolic profile of tomato fruits varies significantly with endogenous ABA levels, season of cultivation and applied stress treatments, highlighting the multifactorial nature of plant responses to combined environmental factors.

Optimization of Germination Conditions for Enriched γ-Aminobutyric Acid and Phenolic Compounds of Foxtail Millet Sprouts by Response Surface Methodology

The optimum germination conditions for foxtail millet sprouts enriched with γ-aminobutyric acid (GABA) and antioxidant polyphenols were investigated. From single-factor experimental results, both the GABA level and total phenolic content (TPC) were more significantly affected by soaking temperature and time, and concentration of sucrose culture solution. Response surface methodology (RSE) was used to optimize the germination conditions of foxtail millet sprouts, where the interaction between soaking temperature and sucrose concentration exhibited a significant (p < 0.05) effect on TPC, and the interaction between soaking time and sucrose concentration displayed a significant (p < 0.05) effect on GABA content. The optimal germination conditions for TPC and GABA enrichment of foxtail millet sprouts were soaking at 31 °C for 4.5 h and germinating at 35 °C with 4.5 g/L sucrose solution for 5 days. Under the optimized conditions, the TPC and GABA content of foxtail millet sprouts were 926.53 milligrams of ferulic acid equivalents per 100 g dry weight (mg FAE/100 g DW) and 259.13 mg/kg, separately, with less difference from the predicted values of 929.44 mg FAE/100 g DW and 263.60 mg/kg, respectively. Collectively, all the individual phenolic compounds increased significantly (p < 0.05) by optimization, except for cis-p-coumaric acid and cis-ferulic acid in bound. The results provide a practical technology for suitable germination conditions to improve the health components of foxtail millet sprouts and increase their added value.

Gum arabic coating alleviates chilling injury of cold-stored peach by regulating reactive oxygen species, phenolic, and sugar metabolism

In this study, gum arabic (GA) coating was employed to mitigate chilling injury in peach fruit, and it was observed that 10% GA coating exhibited the most favorable effect. GA coating significantly inhibited the decline of AsA content and enhanced antioxidant enzyme activity in peach fruit, thereby enhancing reactive oxygen species (ROS) scavenging rate while reducing its accumulation. Simultaneously, GA coating inhibited the activity of oxidative degradation enzymes for phenolics and enhanced synthase activity, thus maintaining higher levels of total phenolics and flavonoids in fruits. Additionally, compared to the control fruit, GA-coated fruits demonstrated higher concentrations of sucrose and sorbitol, accompanied more robust activity of sucrose synthase and sucrose phosphate synthase, as well as reduced activity of acid invertase and neutral invertase. Our study demonstrates that GA coating can effectively enhance the cold resistance of peach fruit by regulating ROS, phenolics, and sugar metabolism, maintaining high levels of phenolics and sucrose while enhancing antioxidant activity.

Recent advances in dietary polyphenols (DPs): antioxidant activities, nutrient interactions, delivery systems, and potential applications

Dietary polyphenols (DPs) have garnered growing interest because of their potent functional properties and health benefits. Nevertheless, the antioxidant capabilities of these substances are compromised by their multifarious structural compositions. Furthermore, most DPs are hydrophobic and unstable when subjected to light, heat, and varying pH conditions, restricting their practical application. Delivery systems based on the interactions of DPs with food constituents such as proteins, polypeptides, polysaccharides, and metal ions are being created as a viable option to improve the functional activities and bioavailability of DPs. In this review, the latest discoveries on the dietary sources, structure-antioxidant activity relationships, and interactions with nutrients of DPs are discussed. It also innovatively highlights the application progress of polyphenols and their green nutraceutical delivery systems. The conclusion drawn is that the various action sites and structures of DPs are beneficial for predicting and designing polyphenols with enhanced antioxidant attributes. The metal complexation of polyphenols and green encapsulation systems display promising outcomes for stabilizing DPs during food processing and in vivo digestion. In the future, more novel targeted delivery systems of DPs for nutrient fortification and intervention should be developed. To expand their usage in customized food products, they should meet the requirements of specific populations for personalized food and nutrition.

Diethyl aminoethyl hexanoate reprogramed accumulations of organic metabolites associated with water balance and metabolic homeostasis in white clover under drought stress

Diethyl aminoethyl hexanoate (DA-6) serving as a non-toxic and low-cost plant growth regulator is used for improving plant growth and stress tolerance, but the DA-6-mediated organic metabolites remodeling in relation to drought tolerance is not well documented in crops. The aims of the present study were to evaluate impacts of DA-6 on physiological functions including osmotic adjustment, photochemical efficiency, oxidative damage, and cell membrane stability as well as organic metabolites remodeling in white clover (Trifolium repens) leaves based on the analysis of metabolomics. Plants were foliarly treated with or without DA-6 and subsequently exposed to drought stress for 8 days. Results demonstrated that foliar application of DA-6 (1.5 mM) could significantly ameliorate drought tolerance, which was linked with better leaf water status, photosynthetic performance, and cell membrane stability as well as lower oxidative injury in leaves. Metabolic profiling of organic metabolites identified a total of 59 metabolites including 17 organic acids, 20 sugars, 12 alcohols, and 10 other metabolites. In response to drought stress, the DA-6 induced accumulations of many sugars and sugar alcohols (erythrulose, arabinose, xylose, inosose, galactose, talopyranose, fucose, erythritol, and ribitol), organic acids (propanoic acid, 2,3-dihydroxybutanoic acid, palmitic acid, linolenic acid, and galacturonic acid), and other metabolites (2-oxazoline, silane, and glycine) in white clover. These altered metabolites induced by the DA-6 could perform critical functions in maintenances of osmo-protection, osmotic adjustment, redox homeostasis, cell wall structure and membrane stability when white clover suffered from water deficit. In addition, the campesterol and stigmasterol significantly accumulated in all plants in spite of the DA-6 pretreatment under drought stress, which could be an important adaptive response to water deficit due to beneficial roles of those two metabolites in regulating cell membrane stability and antioxidant defense. Present findings provide new evidence of DA-6-regulated metabolic homeostasis contributing to drought tolerance in leguminous plants.

Biodegradation of poly-3-hydroxybutyrate after soil inoculation with microbial consortium: Soil microbiome and plant responses to the changed environment

Biodegradable plastics play a vital role in addressing global plastics disposal challenges. Poly-3-hydroxybutyrate (P3HB) is a biodegradable bacterial intracellular storage polymer with substantial usage potential in agriculture. Poly-3-hydroxybutyrate and its degradation products are non-toxic; however, previous studies suggest that P3HB biodegradation negatively affects plant growth because the microorganisms compete with plants for nutrients. One possible solution to this issue could be inoculating soil with a consortium of plant growth-promoting and N-fixing microorganisms. To test this hypothesis, we conducted a pot experiment using lettuce (Lactuca sativa L. var. capitata L.) grown in soil amended with two doses (1 % and 5 % w/w) of P3HB and microbial inoculant (MI). We tested five experimental variations: P3HB 1 %, P3HB 1 % + MI, P3HB 5 %, P3HB 5 % + MI, and MI, to assess the impact of added microorganisms on plant growth and P3HB biodegradation. The efficient P3HB degradation, which was directly dependent on the amount of bioplastics added, was coupled with the preferential utilization of P3HB as a carbon (C) source. Due to the increased demand for nutrients in P3HB-amended soil by microbial degraders, respiration and enzyme activities were enhanced. This indicated an increased mineralisation of C as well as nitrogen (N), sulphur (S), and phosphorus (P). Microbial inoculation introduced specific bacterial taxa that further improved degradation efficiency and nutrient turnover (N, S, and P) in P3HB-amended soil. Notably, soil acidification related to P3HB was not the primary factor affecting plant growth inhibition. However, despite plant growth-promoting rhizobacteria and N2-fixing microorganisms originating from MI, plant biomass yield remained limited, suggesting that these microorganisms were not entirely successful in mitigating the growth inhibition caused by P3HB.

The Potential Effects of Red Wine and Its Components on Neurocognitive Disorders: A Narrative Review

BACKGROUND

The aging population is associated with a net increase in the incidence and prevalence of chronic-degenerative diseases, particularly neurocognitive disorders. Therefore, the identification of preventative strategies to restrain the burden of such chronic conditions is of key relevance. Red wine and its components have accumulated evidence regarding their positive effects in terms of neurological pathologies associated with neurocognitive symptoms.

METHODS

Based on this background, the present narrative review aims to summarize the state-of-the-art evidence on the effects of red wine and its components on neurocognitive disorders in both preclinical and clinical settings.

RESULTS

The main findings highlight a protective effect of wine polyphenols present in red wine on dementia in different preclinical models of cognitive decline. The current translational clinical evidence remains uncertain, especially considering the risk-to-benefit ratio of alcohol consumption on brain health.

CONCLUSIONS

Given the overall health risks associated with red wine consumption and consistent with the prevailing guidelines in the literature, there is insufficient evidence to support light-to-moderate red wine consumption as an effective strategy for preventing these diseases. However, the largely preclinical findings on polyphenols derived from red wine remain of significant interest in this context.

Physiological and molecular responses of a resistant and susceptible wheat cultivar to the fungal wheat pathogen Zymoseptoria tritici

Zymoseptoria tritici is the causal agent of Septoria tritici blotch (STB), one of the most economically destructive wheat foliar diseases. In this study, we explore the physiological and molecular changes elicited in two wheat cultivars with divergent responses (Taichung 29 = susceptible, and Shafir = resistant) upon infection by Z. tritici. Our aim is to uncover novel insights into the intricate mechanisms that govern wheat defense against Z. tritici infection. Our quantitative histopathological study showed that H2O2 accumulated in the resistant cultivar to a higher degree compared to the susceptible cultivar at the biotrophic and switching phase. Additionally, we combined qPCR with a targeted quantitative HPLC technique to evaluate the expression profiles of 13 defense-related genes and profile the polyphenolic compounds induced differentially in the STB susceptible and resistant cultivar. Our finding indicated that five out of 13 genes were strongly up-regulated in the resistant cultivar compared with that of the susceptible one at eight days post-inoculation (dpi), corresponding to the transition phase present in the infection process of Z. tritici. Finally, our targeted HPLC analysis demonstrated that the traced phenolic compounds were highly elevated in the susceptible cultivar infected by Z. tritici compared with that of the resistant cultivar. In conclusion, our comprehensive analysis unveils a robust defense response in the resistant wheat cultivar Shafir, characterized by heightened H2O2 accumulation, significant up-regulation of key defense-related genes during the transition phase, and a distinct profile of polyphenolic compounds, shedding light on the intricate mechanisms contributing to its resistance against Z. tritici, thereby providing valuable insights for the development of more resilient wheat varieties.

Unveiling the impact of nitrogen deficiency on alkaloid synthesis in konjac corms (Amorphophallus muelleri Blume)

BACKGROUND

Konjac corms are known for their alkaloid content, which possesses pharmacological properties. In the primary cultivation areas of konjac, nitrogen deficiency is a common problem that significantly influences alkaloid synthesis. The impact of nitrogen deficiency on the alkaloids in konjac corms remains unclear, further complicated by the transition from mother to daughter corms during their growth cycle.

RESULTS

This study examined 21 alkaloids, including eight indole alkaloids, five isoquinoline alkaloids, and eight other types of alkaloids, along with the associated gene expressions throughout the development of Amorphophallus muelleri Blume under varying nitrogen levels. Nitrogen deficiency significantly reduced corm diameter and fresh weight and delayed the transformation process. Under low nitrogen conditions, the content of indole alkaloids and the expression of genes involved in their biosynthesis, such as tryptophan synthase (TRP) and tryptophan decarboxylase (TDC), exhibited a substantial increase in daughter corms, with fold changes of 61.99 and 19.31, respectively. Conversely, in the mother corm, TDC expression was markedly reduced, showing only 0.04 times the expression level observed under 10 N treatment. The patterns of isoquinoline alkaloid accumulation in corms subjected to nitrogen deficiency were notably distinct from those observed for indole alkaloids. The accumulation of isoquinoline alkaloids was significantly higher in mother corms, with expression levels of aspartate aminotransferase (GOT), chorismate mutase (CM), tyrosine aminotransferase (TAT), and pyruvate decarboxylase (PD) being 4.30, 2.89, 921.18, and 191.40 times greater, respectively. Conversely, in daughter corms, the expression levels of GOT and CM in the 0 N treatment were markedly lower (0.01 and 0.83, respectively) compared to the 10 N treatment.

CONCLUSIONS

The study suggests that under nitrogen deficiency, daughter corms preferentially convert chorismate into tryptophan to synthesize indole alkaloids, while mother corms convert it into tyrosine, boosting the production of isoquinoline alkaloids. This research provides valuable insights into the mechanisms of alkaloid biosynthesis in A. muelleri and can aid in developing nitrogen fertilization strategies and in the extraction and utilization of alkaloids.

Integrated transcriptomics, metabolomics and physiological analyses reveal differential response mechanisms of wheat to cadmium and/or salinity stress

Many soils face dual challenges of cadmium (Cd) contamination and salinization. However, the response of crops, especially wheat, to combined Cd and salinity stress is not understood. Here, wheat was grown in a hydroponic model for 14 days under single and combined Cd and NaCl stresses. Growth parameters, tissue Cd2+ and Na+ contents, and leaf chlorophyll (Chl), O2•-, and MDA levels were determined. Comparative transcriptomic and metabolomic analyses of the leaves were performed. The results showed that combined stress had a greater inhibitory effect on Chl contents and generated more O2•- and MDA, resulting in more severe wheat growth retardation than those under Cd or NaCl stress. Stress-induced decrease in Chl levels may be attributed to the inhibition of Chl biosynthesis, activation of Chl degradation, or a decline in glutamate content. Cd addition weakened the promotional effect of NaCl on SOS1 gene expression, thereby increasing the Na+ content. Contrastingly, NaCl supplementation downregulated the Nramp and ZIP gene expressions related to Cd uptake and transport, thereby impeding Cd2+ accumulation. All stresses enhanced tryptophan content via promoting tryptophan biosynthesis. Meanwhile, Cd and NaCl stresses activated phenylpropanoid biosynthesis and purine metabolism, respectively, thereby increasing the levels of caffeic acid, fumaric acid, and uric acid. Activating the TCA cycle was important in the wheat's response to combined stress. Additionally, NaCl and combined stresses affected starch and sucrose metabolism, resulting in sucrose and trehalose accumulation. Our findings provide a comprehensive understanding of the response of wheat to the combined Cd and salinity stress.

Silicon-mediated resilience: Unveiling the protective role against combined cypermethrin and hymexazol phytotoxicity in tomato seedlings

Insecticides and fungicides present potential threats to non-target crops, yet our comprehension of their combined phytotoxicity to plants is limited. Silicon (Si) has been acknowledged for its ability to induce crop tolerance to xenobiotic stresses. However, the specific role of Si in alleviating the cypermethrin (CYP) and hymexazol (HML) combined stress has not been thoroughly explored. This study aims to assess the effectiveness of Si in alleviating phytotoxic effects and elucidating the associated mechanisms of CYP and/or HML in tomato seedlings. The findings demonstrated that, compared to exposure to CYP or HML alone, the simultaneous exposure of CYP and HML significantly impeded seedling growth, resulting in more pronounced phytotoxic effects in tomato seedlings. Additionally, CYP and/or HML exposures diminished the content of photosynthetic pigments and induced oxidative stress in tomato seedlings. Pesticide exposure heightened the activity of both antioxidant and detoxification enzymes, increased proline and phenolic accumulation, and reduced thiols and ascorbate content in tomato seedlings. Applying Si (1 mM) to CYP- and/or HML-stressed seedlings alleviated pigment inhibition and oxidative damage by enhancing the activity of the pesticide metabolism system and secondary metabolism enzymes. Furthermore, Si stimulated the phenylpropanoid pathway by boosting phenylalanine ammonia-lyase activity, as confirmed by the increased total phenolic content. Interestingly, the application of Si enhanced the thiols profile, emphasizing its crucial role in pesticide detoxification in plants. In conclusion, these results suggest that externally applying Si significantly alleviates the physio-biochemical level in tomato seedlings exposed to a combination of pesticides, introducing innovative strategies for fostering a sustainable agroecosystem.

24-Epibrassinolide mitigates arsenate stress in seedlings of Oryza sativa (IR-20) via the induction of phenylpropanoid pathway

The introduction of arsenic, a hazardous metalloid, into the soil system due to heavy industrialization has negatively affected agricultural productivity, resulting in limited crop yields. A recent breakthrough in stress-responsive hormones, specifically brassinosteroids, has extensively covered the role of antioxidant enzyme defense systems in heavy metal stress mitigation. Considering the antioxidant properties and metal complex formation abilities of polyphenols, our study focuses on examining their role in arsenate toxicity amelioration by 24-epibrassinolide. We demonstrate enhanced growth parameters of sodium arsenate-stressed seedlings upon application of 24-epibrassinolide, with increased root and shoot polyphenol levels analyzed by high-performance liquid chromatography. Specifically, the concentration of catechin, sinapic acid, 4-hydroxy benzoic acid, protocatechuic acid, 4-coumaric acid, and myricetin were elevated, indicating induction of phenylpropanoid signaling pathway. Further, we also report a decrease in the generation of superoxide anions and hydrogen peroxide validated the antioxidant effects of these metabolites through the nitrobluetetrazolium and diaminobenzidine staining method. In addition, evaluation of transcript level of genes encoding for specific enzymes of the phenylpropanoid pathway in shoot and root showed a significant upregulation in mRNA expression of phenylalanine ammonia-lyase-1, cinnamate-4-hydroxylase, and caffeic acid o-methyltransferase-1 upon exogenous application of 24-epibrassinolide in arsenate stressed Oryza sativa.

Towards Characterization of Hass Avocado Peel and Pulp Proteome during Postharvest Shelf Life

In recent years, avocados have gained worldwide popularity as a nutritive food. This trend is causing a rise in the production of this fruit, which is accompanied by several problems associated with monocultural practices. Despite massive economic gains, limited molecular and structural information has been generated about avocado ripening. In fact, limited studies have attempted to unravel the proteome complexity dynamics of avocado fruit. We therefore conducted a comparative proteomics study on avocado peel and pulp during the postharvest shelf life using tandem mass tag synchronous precursor selection triple-stage mass spectrometry. We identified 3161 and 1128 proteins in the peel and pulp, respectively. Peels exhibited major over-accumulation of proteins associated with water deprivation and oxidative stress, along with abscisic acid biosynthesis. Ethylene, jasmonic acid, phenylpropanoid, and flavonoid biosynthesis pathways were activated. Structurally, we observed the accumulation of lignin and a reduction in cuticular thickness, which coincides with the reduction in the levels of long-chain acyl-coenzyme A synthetase and a marginal increase in 10,16-dihydroxyhexadecanoic acid. Our study sheds light on the association of proteome modulation with the structural features of Hass avocado. Its detailed characterization will provide an alternative for better preservation during the postharvest period.

Azolla pinnata as a phytoremediator: improves germination, growth and yield of maize irrigated with Ni-polluted water

The removal of pollutants from the environment has become a global demand. The current study aimed to relieve the Ni toxicity effect on the germination, growth, and grain yield of maize by using Azolla pinnata as a phytoremediator. Azolla-treated and untreated nickel solutions [0 (control), 24, 70, 140 and 190 ppm] were applied for germination and pot experiments. Electron microscope examination cleared the Ni accumulation in Azolla's cell vacuole and its adsorption on the cell wall. The inhibition of the hydrolytic enzyme activity reduces maize germination; maximal inhibition was 57.1% at 190 ppm of Ni compared to the control (100%). During vegetative growth, Ni stimulated the generation of H2O2 (0.387 mM g-1 F Wt at 190 ppm of Ni), which induced maximal lipid peroxidation (3.913 µMDA g-1 F Wt) and ion leakage (74.456%) compared to control. Chlorophyll content and carbon fixation also showed significant reductions at all Ni concentrations; at 190 ppm, they showed maximum reductions of 56.2 and 63%, respectively. However, detoxification enzymes' activity such as catalase and antioxidant substances (phenolics) increased. The highest concentration of Ni (190 ppm) had the most effect on constraining yield, reaching zero for the weight of 100 grains at 190 ppm of Ni. Azolla-treated Ni solutions amended all determinant parameters, indicating a high percentage of changes in hydrolytic enzyme activity (125.2%) during germination, chlorophyll content (77.6%) and photosynthetic rate (120.1%). Growth measurements, carbon fixation, and yield components showed a positive association. Thus, we recommended using Azolla as a cost-effective and eco-friendly strategy to recover Ni-polluted water.

Silicon alleviates the toxicity of microplastics on kale by regulating hormones, phytochemicals, ascorbate-glutathione cycling, and photosynthesis

Kale is rich in various essential trace elements and phytochemicals, including glucosinolate and its hydrolyzed product isothiocyanate, which have significant anticancer properties. Nowadays, new types of pollutant microplastics (MP) pose a threat to global ecosystems due to their high bioaccumulation and persistent degradation. Silicon (Si) is commonly used to alleviate abiotic stresses, offering a promising approach to ensure safe food production. However, the mechanisms through which Si mitigates MP toxicity are unknown. In this study, a pot culture experiments was conducted to evaluate the morphogenetic, physiological, and biochemical responses of kale to Si supply under MP stress. The results showed that MP caused the production of reactive oxygen species, inhibited the growth and development of kale, and reduced the content of phytochemicals by interfering with the photosynthetic system, antioxidant defense system, and endogenous hormone regulation network. Si mitigated the adverse effects of MP by enhancing the photosynthetic capacity of kale, regulating the distribution of substances between primary and secondary metabolism, and strengthening the ascorbate-glutathione (AsA-GSH) cycling system.

Enhancing Red Table Grape Coloration Using Tsikoudia: A Novel and Sustainable Approach

Achieving optimal coloration in red table grapes, especially in warm-climate regions, presents significant challenges due to high temperatures that inhibit anthocyanin biosynthesis. Conventional methods to enhance grape coloration, including the use of abscisic acid (ABA), ethephon, foliar nutrient supplementation, and viticultural practices like cluster trimming and girdling, have limitations related to cost, regulatory restrictions, and potential adverse effects on grapes quality. This study proposes the application of tsikoudia, a traditional Greek alcoholic beverage, as a novel, sustainable, and cost-effective alternative to conventional practices. Tsikoudia, applied during the veraison stage, significantly improved the coloration of 'Crimson Seedless' and 'Red Globe' grapes by enhancing anthocyanin accumulation and altering color parameters. Specifically, lightness (L*), chroma (C*), and hue angle (h), measured using the CIE-Lab color system, were reduced, while the Color Index for Red Grapes (CIRG) was increased. Additionally, total anthocyanin content, determined through spectrophotometric analysis, also showed an increase. These changes indicate a more intense red coloration. This research highlights the effectiveness of tsikoudia in improving grape coloration and contributes to the development of more sustainable viticultural practices.

Comprehensive, Genome-Wide Identification and Expression Analyses of Phenylalanine Ammonia-Lyase Family under Abiotic Stresses in Brassica oleracea

Phenylalanine ammonia-lyase (PAL) acts as the rate-limiting enzyme for anthocyanin biosynthesis through the phenylpropanoid pathway, a crucial component of plant secondary metabolism. The PAL gene family plays a crucial role in plants' defense and stress responses, but its in silico identification and expression analyses in Brassica oleracea under different abiotic stresses remain unexplored. In this study, nine BolPAL, seven BrPAL, four AtPAL, and seventeen BnPAL genes were obtained from the genomes of B. oleracea, Brassica rapa, Arabidopsis thaliana, and Brassica napus, respectively. Segmental duplication and purifying selection are the causes of the BolPAL gene's amplification and evolution. The BolPAL genes with comparable intron-exon architectures and motifs were grouped together in the same clade. Three categories comprised the cis-regulatory elements: abiotic stressors, phytohormones, and light. According to the results of the qRT-PCR experiments, the majority of the BolPAL genes were expressed highly under MeJA, a low temperature, and a high temperature, and they were downregulated under ABA. Under white light (100 µmol m-2 s-1) with 50, 100, or 150 µmol m-2 s-1 far-red (FR), only a small number of the PAL genes were expressed at 50 and 100 µmol m-2 s-1 FR, while the majority of the PAL genes were slightly elevated at 150 µmol m-2 s-1 FR. This work offers a theoretical foundation for molecular breeding research to investigate the role of BolPAL genes and their role in anthocyanin biosynthesis.

Integrative multi-omics analysis reveals the underlying toxicological mechanisms of enrofloxacin on the growth of wheat seedling roots

The continuous release of antibiotics into agroecosystems has raised concerns about the potential negative effects of antibiotic residues on crops. In this study, the toxicological effects of enrofloxacin (ENR) on wheat seedlings were analyzed using a combination of morpho-physiological, transcriptomic, proteomic, and metabolomic approaches. ENR inhibited the growth of wheat (Triticum aestivum L.) roots and induced oxidative stress. In particular, ENR downregulated the oxidative phosphorylation pathway, while it enhanced glycolysis and the tricarboxylic acid cycle, thereby regulating the balance of intracellular energy metabolism. In addition, sustained exposure to excessive reactive oxygen species (ROS) resulted in an increase in reduced glutathione (GSH), a slight decrease in ascorbic acid (AsA), and a significant decrease in the ratio of GSH to oxidized glutathione (GSSG), which imbalanced the AsA-GSH cycle. In addition, the resulting increase in abnormal proteins triggered ubiquitin-independent proteasomal degradation pathways. Further, an increase in abscisic acid (ABA) and a decrease in jasmonic acid (JA) and its derivatives alleviated the inhibitory effect of ENR on the growth of wheat roots. In conclusion, direct damage and signaling by ROS, hormonal regulation, a decrease in the GSH to GSSG ratio, and insufficient energy supply were identified as key factors for the significant inhibition of wheat root growth under ENR stress.

McWRKY43 Confers Cold Stress Tolerance in Michelia crassipes via Regulation of Flavonoid Biosynthesis

WRKY transcription factor (TF) plays a crucial role in plant abiotic stress response, but it is rarely reported in Michelia crassipes. Our studies have found that the transcription factor McWRKY43, a member of the IIc subgroup, is strongly upregulated under cold stress. In this study, we cloned the full length of McWRKY43 to further investigate the function of McWRKY43 in resistance to cold stress and its possible regulatory pathways in M. crassipes. Under cold stress, the seed-germination rate of transgenic tobacco was significantly higher than that of the wild type, and the flavonoid content, antioxidant enzyme activities, and proline content of transgenic tobacco seedlings were significantly increased, which promoted the expression of flavonoid pathway structural genes. In addition, the transient transformation of McWRKY43 in the M. crassipes leaves also found the accumulation of flavonoid content and the transcription level of flavonoid structural genes, especially McLDOX, were significantly increased under cold stress. Yeast one-hybrid (Y1H) assay showed that McWRKY43 could bind to McLDOX promoter, and the transcription expression of McLDOX was promoted by McWRKY43 during cold stress treatment. Overall, our results indicated that McWRKY43 is involved in flavonoid biosynthetic pathway to regulate cold stress tolerance of M. crassipes, providing a basis for molecular mechanism of stress resistance in Michelia.

Comparative metabolites profiling of different solvent extracts of Asparagus species cladodes using liquid chromatography-mass spectrometry-based metabolomics and molecular networking

INTRODUCTION

Asparagus species are naturally distributed worldwide and are known for their pharmacological properties that offer cures for various ailments. However, the metabolic choreography of these Asparagus species is not well characterized, and the compounds contributing to their bioactivities remain unknown.

OBJECTIVE

This study aimed to profile and compare the metabolomes of three Asparagus species cladodes using different solvent extractions.

METHODS

An ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry-based metabolomics and molecular networking approach was used to study the effects of different solvents (ethyl acetate, methanol, and chloroform) with varying polarity on metabolites extraction and identification of bioactive compounds from three Asparagus species cladodes (Asparagus falcatus, Asparagus plumosus, and Asparagus densiflorus 'Meyersii').

RESULTS

Multivariate statistical analyses (mainly principal component analysis) revealed a significant separation between the three solvents and the three species, indicating notable metabolic differences. A total of 118 metabolites were identified in the three species extracted with the different solvents, with methanolic and chloroform extracts containing more metabolites compared with ethyl acetate extracts. These metabolites were identified as belonging to the flavonoids, cinnamic acids, organooxygen compounds, steroids, fatty acids, benzenes, and glycerophospholipids compound classes. Furthermore, these compounds classes were differentially distributed among the three species, indicating chemical/chemotaxis differences between the compared species. Chloroform and methanol are recommended as the optimal solvents to obtain a high content of phytochemical compounds from Asparagus species cladodes.

Applicability of metabolomics to improve sustainable grapevine production

Metabolites represent the end product of gene expression, protein interaction and other regulatory mechanisms. The metabolome reflects a biological system's response to genetic and environmental changes, providing a more accurate description of plants' phenotype than the transcriptome or the proteome. Grapevine (Vitis vinifera L.), established for the production of wine grapes, table grapes, and raisins, holds immense agronomical and economic significance not only in the Mediterranean region but worldwide. As all plants, grapevines face the adverse impact of biotic and abiotic stresses that negatively affect multiple stages of grape and wine industry, including plant and berry development pre- and post-harvest, fresh grapes processing and consequently wine quality. In the present review we highlight the applicability of metabolome analysis in the understanding of the mechanisms involved in grapevine response and acclimatization upon the main biotic and abiotic constrains. The metabolome of induced morphogenic processes such as adventitious rooting and somatic embryogenesis is also explored, as it adds knowledge on the physiological and molecular phenomena occurring in the explants used, and on the successfully propagation of grapevines with desired traits. Finally, the microbiome-induced metabolites in grapevine are discussed in view of beneficial applications derived from the plant symbioses.

Genome-wide transcriptome and gene family analysis reveal candidate genes associated with potassium uptake of maize colonized by arbuscular mycorrhizal fungi

BACKGROUND

Potassium (K) is an essential nutrient for plant growth and development. Maize (Zea mays) is a widely planted crops in the world and requires a huge amount of K fertilizer. Arbuscular mycorrhizal fungi (AMF) are closely related to the K uptake of maize. Genetic improvement of maize K utilization efficiency will require elucidating the molecular mechanisms of maize K uptake through the mycorrhizal pathway. Here, we employed transcriptome and gene family analysis to elucidate the mechanism influencing the K uptake and utilization efficiency of mycorrhizal maize.

METHODS AND RESULTS

The transcriptomes of maize were studied with and without AMF inoculation and under different K conditions. AM symbiosis increased the K concentration and dry weight of maize plants. RNA sequencing revealed that genes associated with the activity of the apoplast and nutrient reservoir were significantly enriched in mycorrhizal roots under low-K conditions but not under high-K conditions. Weighted gene correlation network analysis revealed that three modules were strongly correlated with K content. Twenty-one hub genes enriched in pathways associated with glycerophospholipid metabolism, glycerolipid metabolism, starch and sucrose metabolism, and anthocyanin biosynthesis were further identified. In general, these hub genes were upregulated in AMF-colonized roots under low-K conditions. Additionally, the members of 14 gene families associated with K obtain were identified (ARF: 38, ILK: 4, RBOH: 12, RUPO: 20, MAPKK: 89, CBL: 14, CIPK: 44, CPK: 40, PIN: 10, MYB: 174, NPF: 79, KT: 19, HAK/HKT/KUP: 38, and CPA: 8) from maize. The transcript levels of these genes showed that 92 genes (ARF:6, CBL:5, CIPK:13, CPK:2, HAK/HKT/KUP:7, PIN:2, MYB:26, NPF:16, RBOH:1, MAPKK:12 and RUPO:2) were upregulated with AM symbiosis under low-K conditions.

CONCLUSIONS

This study indicated that AMF increase the resistance of maize to low-K stress by regulating K uptake at the gene transcription level. Our findings provide a genome-level resource for the functional assignment of genes regulated by K treatment and AM symbiosis in K uptake-related gene families in maize. This may contribute to elucidate the molecular mechanisms of maize response to low K stress with AMF inoculation, and provided a theoretical basis for AMF application in the crop field.

Synergistic role of phenylpropanoid biosynthesis and citrate cycle pathways in heavy metal detoxification through secretion of organic acids

Excessive heavy metal contaminants in soils have serious ecological and environmental impacts, and affect plant growth and crop yields. Phytoremediation is an environmentally friendly means of lowering heavy metal concentrations in soils. In this study, we analyzed phenotypic and physiological traits, and the transcriptome and metabolome, of sheepgrass (Leymus chinensis) exposed to cadmium (Cd), lead (Pb), or zinc (Zn). Phenotypic and physiological analysis indicated that sheepgrass had strong tolerance to Cd/Pb/Zn. Transcriptomic analysis revealed that phenylpropanoid biosynthesis and organic acid metabolism were enriched among differentially expressed genes, and metabolomic analysis indicated that the citrate cycle was enriched in response to Cd/Pb/Zn exposure. Genes encoding enzymes involved in the phenylpropanoid and citrate cycle pathways were up-regulated under the Cd/Pb/Zn treatments. Organic acids significantly reduced heavy metal accumulation and improved sheepgrass tolerance of heavy metals. The results suggest that synergistic interaction of the phenylpropanoid and citrate cycle pathways in sheepgrass roots induced organic acid secretion to alleviate heavy metal toxicity. A cascade of enzymes involved in the interacting pathways could be targeted in molecular design breeding to enhance phytoremediation.

Silicon-Mediated Improvement in Drought and Salinity Stress Tolerance of Black Gram (Vigna mungo L.) by Modulating Growth, Physiological, Biochemical, and Root Attributes

Water is a precious commodity for plant growth and metabolism; however, its scarcity and saline sand conditions have a drastic effect on plant growth and development. The main objective of the current study was to understand how silicon (Si) application might help Black gram (Vigna mungo L.) against the negative impacts of salt stress and drought. The treatments of this study were: no silicon = 0 mg/kg; silicon = 40 mg/kg; control = no stress; drought stress = 50% field capacity (FC); salinity = 10 dSm-1; drought + salinity = 10 dSm-1 + 50% field capacity (FC). The findings showed that the application of silicon in the sand significantly affected growth indices such as leaf area (LA), shoot fresh weight (SFW), shoot dry weight (SDW), and shoot length (SL). Root length (RL) increased significantly up to 55.9% in response to drought stress. Applying Si to the sand increased the root length (RL) by 53.9%. In comparison to the control, the turgor potential of leaves decreased by 10.3% under salinity, while it increased by 44.7% under drought stress. However, the application of silicon to the sand significantly improved the turgor potential of leaves by 98.7%. Under both drought and salt stress, gas exchange characteristics and photosynthetic pigments dramatically decreased. Applying 40 mg/kg silicon to sand improved the gas exchange characteristics, protein contents, and photosynthetic pigments of plants under drought and salt stress, such as levels of chlorophyll (a, and b) increased by 18% and 26%, respectively. Under control conditions, the hydrogen peroxide (H2O2) concentration was lower but increased during periods of drought and salinity stress. The concentrations of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) were decreased by salt and drought stress and increased by sand application of silicon at a rate of 40 mg/kg. Application of silicon at 40 mg/kg sand rate improved the growth and development under control and stress conditions. Overall, this study provides an extensive understanding of the physiological mechanisms underlying the black gram's ability to withstand under salt stress and drought stress by application of Si which will serve as a roadmap for future cellular research.

Gallic acid regulates primary root elongation via modulating auxin transport and signal transduction

Gallic acid is an important secondary metabolite in plants, with great value in medicine, food, and chemical industry. However, whether and how this widely existing natural polyphenolic compound affects the growth and development of plants themselves remains elusive. In this study, we revealed that exogenous application of gallic acid has a dual effect on the elongation of primary root in Arabidopsis. While lower concentrations of gallic acid slightly stimulate primary root growth, excessive gallic acid profoundly reduces primary root length and root meristem size in a dose-dependent manner, probably via suppressing cell division in root meristem as indicated by CYCB1;1::GUS. Moreover, as suggested by the DR5::GFP line analysis and confirmed by the LC-MS assay, auxin contents in root tips were dramatically decreased upon excessive gallic acid treatment. Additional application of IAA partially rescued the shortened primary root and root meristem upon excessive gallic acid treatment, suggesting that auxin is required for excessive gallic acid-caused root growth inhibition. Then, we further revealed that excessive gallic acid down-regulated the expression of auxin transporters PIN1, PIN2, PIN3, and PIN7, and triple mutant pin1 pin3 pin7 exhibited a reduced sensitivity to gallic acid treatment. Meanwhile, excessive gallic acid decreased the degradation of AXR3/IAA17 protein as revealed by HS::AXR3NT-GUS reporter line. Auxin signaling mutant tir1 afb2 afb3 and axr3-3 were also less sensitive to excessive gallic acid treatment in terms of primary root length and root meristem size. Taken together, these findings suggested that excessive gallic acid inhibits primary root growth by modulating auxin transport and signaling in Arabidopsis.

Strategies for adaptation to high light in plants

Plants absorb light energy for photosynthesis via photosystem complexes in their chloroplasts. However, excess light can damage the photosystems and decrease photosynthetic output, thereby inhibiting plant growth and development. Plants have developed a series of light acclimation strategies that allow them to withstand high light. In the first line of defense against excess light, leaves and chloroplasts move away from the light and the plant accumulates compounds that filter and reflect the light. In the second line of defense, known as photoprotection, plants dissipate excess light energy through non-photochemical quenching, cyclic electron transport, photorespiration, and scavenging of excess reactive oxygen species. In the third line of defense, which occurs after photodamage, plants initiate a cycle of photosystem (mainly photosystem II) repair. In addition to being the site of photosynthesis, chloroplasts sense stress, especially light stress, and transduce the stress signal to the nucleus, where it modulates the expression of genes involved in the stress response. In this review, we discuss current progress in our understanding of the strategies and mechanisms employed by plants to withstand high light at the whole-plant, cellular, physiological, and molecular levels across the three lines of defense.

Deciphering the role of nitric oxide in mitigation of systemic fungicide induced growth inhibition and oxidative damage in wheat

Consento (CON) poses a significant environmental hazard as a systemic fungicide, adversely affecting the health of non-target organisms. Nitric oxide (NO), a signaling molecule, is known to play a crucial role in plant physiology and abiotic stress tolerance. However, whether NO plays any role to enhance fungicide CON tolerance in wheat seedlings is yet unclear. Therefore, we conducted a hydroponic experiment i) to investigate the morpho-physio-biochemical changes of wheat seedlings to fungicide CON stress, and ii) to examine the effects of NO and fungicide CON treatments on oxidative damage, antioxidant system, secondary metabolism and detoxification of systemic fungicide in wheat seedlings. The results showed that CON fungicide at the highest (4X) concentration significantly decreased wheat seedlings fresh weight (46.89%), shoot length (40.26%), root length (56.11%) and total chlorophyll contents (67.44%) in a dose response relationship. Moreover, CON significantly increased hydrogen peroxide, malondialdehyde, catalase, ascorbate peroxidase, glutathione-S-transferase, and peroxidase activities while decreased reduced glutathione (GSH) content. This ultimately impaired the redox homeostasis of cells, leading to oxidative damage in cell membrane. Under fungicide treatment, the addition of NO reduced the fungicide phytotoxicity, with an increase of over 60% in seedling growth. The NO application mitigated CON phytotoxicity as reflected by significantly increased chlorophyll pigments (69.88%) and decreased oxidative damage in wheat leaves. Indeed, the NO alleviatory effect was able to increase the tolerance of seedlings to fungicide, which resulted increments in antioxidant and detoxification enzymes activity, with the enhanced GSH level (78.54%). Interestingly, NO alleviated CON phytotoxicity through the phenylpropanoid pathway by enhancing the activity of secondary metabolism enzymes such as phenylalanine ammonia-lyase (47.28%), polyphenol oxidase (9%), and associated metabolites such as phenolic acids (77.62%), flavonoids (34.33%) in wheat leaves. Our study has provided evidence that NO plays a key role in the metabolism and detoxification of systemic fungicide in wheat through enhanced activity of antioxidants, detoxifications and secondary metabolic enzymes.

Multi-omics integration analysis reveals the molecular mechanisms of drought adaptation in homologous tetraploid alfalfa(Medicago sativa 'Xinjiang-Daye')

Drought stress is a predominant abiotic factor leading to decreased alfalfa yield. Genomic ploidy differences contribute to varying adaptation mechanisms of different alfalfa cultivars to drought conditions. This study employed a multi-omics approach to characterize the molecular basis of drought tolerance in a tetraploid variant of alfalfa (Medicago sativa, Xinjiang-Daye). Under drought treatment, a total of 4446 genes, 859 proteins, and 524 metabolites showed significant differences in abundance. Integrative analysis of the multi-omics data revealed that regulatory modules involved in flavonoid biosynthesis, plant hormone signalling transduction, linoleic acid metabolism, and amino acid biosynthesis play crucial roles in alfalfa adaptation to drought stress. The severity of drought led to the substantial accumulation of flavonoids, plant hormones, free fatty acids, amino acids, and their derivatives in the leaves. Genes such as PAL, 4CL, CHI, CHS, PP2C, ARF_3, and AHP_4 play pivotal regulatory roles in flavonoid biosynthesis and hormone signalling pathways. Differential expression of the LOX gene emerged as a key factor in the elevated levels of free fatty acids. Upregulation of P5CS_1 and GOT1/2 contributed significantly to the accumulation of Pro and Phe contents. ERF19 emerged as a principal positive regulator governing the synthesis of the aforementioned compounds. Furthermore, observations suggest that Xinjiang-Daye alfalfa may exhibit widespread post-transcriptional regulatory mechanisms in adapting to drought stress. The study findings unveil the critical mechanisms by which Xinjiang-Daye alfalfa adapts to drought stress, offering novel insights for the improvement of alfalfa germplasm resources.

Identification of crucial metabolites in colored grain wheat (Triticum aestivum L.) regulated by nitrogen application

Colored wheats have drawn attention due to their nutritional compounds. However, limited information is obtained on the effects of nitrogen fertilizer on crucial metabolites and grain quality of wheats with different color grain. In the study, the pot experiment was conducted with white (W), blue (B), and purple (P) grain wheats treated with three levels of N (LN, 0 g kg-1; MN, 0.05 g kg-1; HN, 0.1 g kg-1). Higher N level could promote wheat growth, improve grain indexes, and nutrient uptake. SPAD values of flag leaves remained in the order HN > MN > LN across all wheat varieties, and maintained increasing during tested stages under purple wheat. Metabolomics analysis showed that the annotated 358 metabolites mainly belonged to 29 classes, including carboxylic acids and their derivatives, fatty acids, flavonoids, and phenols. 35, 39, and 70 differential accumulated metabolites were respectively found between the WLN vs. WHN, the BHN vs. BLN, and the PHN vs. PLN, which were mainly enriched in "biosynthesis of plant secondary metabolites", "cGMP-PKG signaling pathway", "sphingolipid signaling pathway", "biosynthesis of alkaloids derived from histidine and purine", and "biosynthesis of plant hormones". Additionally, erucic acid was dominated in the three wheat cultivars, and was decreased after treated with high N levels. Our study preliminarily revealed the different response mechanisms to different N levels in the white, blue, and purple grain wheats, and lay a theoretical foundation for further breeding of excellent colored grain varieties.

NtWIN1 regulates the biosynthesis of scopoletin and chlorogenic acid by targeting NtF6'H1 and NtCCoAMT genes in Nicotiana tabacum

Scopoletin and chlorogenic acid (CGA) are important polyphenols that regulate plant growth, development, and stress resistance. The ERF transcription factor WAX INDUCER1 (WIN1) promotes the biosynthesis of cutin, suberine, and wax. However, its full roles in regulating the accumulation of plant secondary metabolites still remain to be further clarified. In this study, NtWIN1 gene encoding a SHINE-type AP2/ERF transcription factor of the Va subgroup was identified from N. tabacum. NtWIN1 showed high expression levels in tobacco stems, sepals, and pistils. Overexpression (OE) and knock-out of NtWIN1 showed that it promoted the accumulation of total polyphenols and altered their composition. Compare to that of WT plants, the CGA contents significantly increased by 25%-50% in the leaves, flowers, and capsules of OE lines, while the scopoletin contents in the OE plants significantly decreased by 30%-67%. In contrast, the CGA contents in ntwin1 lines reduced by 23%-26%, and the scopoletin contents in ntwin1 increased by 38%-75% compare to that of WT plants. Chromatin immunoprecipitation and Dual-Luc transcription activation assays showed that NtWIN1 could bind to the promoters of NtF6'H1 and NtCCoAMT, thereby modulating their expression. The scopoletin content in ntwin1/ntf6'h1 double mutant was significantly lower than that in ntwin1 and WT plants, but showed no significant differences with that in ntf6'h1 mutant, further indicating that the inhibition of NtWIN1 on scopoletin accumulation depends on the activity of NtF6'H1. Our study illustrates the new roles of NtWIN1, and provides a possible target for regulating the synthesis of polyphenols in tobacco.

Arbuscular mycorrhizal fungi regulate amino acid metabolism, phytohormones and glycolysis pathway to promote the growth of Suaeda salsa under combined Cd and NaCl stresses

The use of halophytes in conjunction with arbuscular mycorrhizal (AM) fungi has been found to enhance the removal efficacy of heavy metals and salts in heavy metals contaminated saline soil. The mechanisms of AM fungi on promoting halophyte growth and regulating metabolism remain unclear. In this study, combinations of 0 g kg-1 NaCl and 3 mg kg-1 Cd (S0Cd3), 6 g kg-1 NaCl and 3 mg kg-1 Cd (S6Cd3), and 12 g kg-1 NaCl and 3 mg kg-1 Cd (S12Cd3) were employed to explore the impact of Funneliformis mosseae on the growth and metabolism of Suaeda salsa. The results showed that AM fungi increased the biomass and the P, K+, Ca2+, and Mg2+ accumulations, reduced the Cd and Na+ concentrations in S0Cd3 and S6Cd3, and increased the Cd concentrations in S12Cd3. AM fungi inoculation reduced the Cd and Na+ transfer factors and increased the Cd and Na+ accumulations in S6Cd3. The metabolomics of S6Cd3 showed that AM fungi upregulated the expression of 5-hydroxy-L-tryptophan and 3-indoleacid acid in tryptophan metabolism, potentially acting as crucial antioxidants enabling plants to actively cope with abiotic stresses. AM fungi upregulated the expression of arbutin in glycolysis process, enhancing the plants' osmoregulation capacity. AM fungi upregulated the expression of 2-hydroxycinnamic acid in phenylalanine metabolism and dopaquinone in tyrosine metabolism. These two metabolites help effectively remove reactive oxygen species. Correspondingly, AM fungi decreased MDA content and increased soluble sugar content. These results indicate that AM fungi improve the stress resistance of S. salsa by increasing nutrient uptake and regulating physiological and metabolic changes.

Vasorelaxant effect of phenylpropanoids: Methyl eugenol and eugenol in human umbilical cord vein

Methyl-eugenol (ME) and eugenol (EUG) are phenylpropanoids with vasodilatory effects. While EUG's vasorelaxant effect in human umbilical artery (HUA) is known, their action in veins is unclear. This study aimed to evaluate ME and EUG in human umbilical vein (HUV). Isolated HUV underwent tension recordings. ME and EUG caused 100 % relaxation in HUV, with EC50 values corresponding to: 174.3 ± 7.3 and 217.3 ± 6.2 µM for ME and EUG respectively in presence of K+; 362.3 ± 5.4 and 227.7 ± 4.9 µM for ME and EUG respectively and in presence of serotonin (5-HT). It was observed that in presence of BaCl2 and CaCl2 evoked contractions, ME (800 and 1000 µM) and EUG (1000 and 1400 µM) prevent the contractions. In presence of K+ channel blockers it was observed that ME promoted relaxation compared to its control, except in presence of 4-AP, suggesting a possible Ca2+-dependent K+ channel activation for this molecule; EUG increased all EC50 in presence of the K+ blockers except in presence of TEA 1 mM. Greater pharmacological potency was observed for ME. This study highlights natural substances' effects on HUV contractile parameters, suggesting ME and EUG as potential vasodilators in maintaining fetal oxygenation and venous flow during gestational hypertensive syndromes.

Digestate Improves Stinging Nettle (Urtica dioica) Growth and Fiber Production at a Chlor-Alkali Site

Marginal lands have been proposed to produce non-food crop biomass for energy or green materials. For this purpose, the selection, implementation, and growth optimization of plant species on such lands are key elements to investigate to achieve relevant plant yields. Stinging nettle (Urtica dioica) is a herbaceous perennial that grows spontaneously on contaminated lands and was described as suitable to produce fibers for material applications. Two mercury-contaminated soils from industrial wastelands with different properties (grassland soil and sediment landfill) were used in this study to assess the potential growth of stinging nettle in a greenhouse mesocosm experiment. Two organic amendments were studied for their impact on nettle growth. The solid digestate from organic food wastes significantly doubled plant biomass whereas the compost from green wastes had a lower impact. The highest doses of organic amendments significantly increased the number of fibers, which doubled following digestate application, while reducing leaf Hg concentration. Both amendments significantly improved soil respiration and enzymatic activities linked to the microbial biomass in the soil from the sediment landfill by the end of the experiment. In the context of a phytomanagement scenario, solid digestate would be a preferred amendment resource to improve nettle production on industrial wastelands.

UHPLC-DAD/ESI-TOF-MS Phytochemical Characterization and Evaluation of the Impact of Eleutherococcus senticosus Fruit Intractum on Biochemical, Hepatological, and Blood Parameters in Balb/c Mice

Eleutherococcus senticosus (Rupr. et Maxim.) Maxim. (ES) has gained popularity for its adaptogenic, immunostimulant, and anti-inflammatory properties. Because of overexploitation of the roots, the species is considered to be endangered and has been put on the Red List in some countries (e.g., the Republic of Korea). Therefore, the fruits of E. senticosus might be explored as a new sustainable source of compounds with adaptogenic activity. This study aimed to assess the chemical composition and the safety profile (hepatotoxicity, blood morphology, biochemical parameters of blood plasma) of E. senticosus fruit intractum in Balb/c mice after oral administration of 750 and 1500 mg/kg b.w. UHPLC analysis coupled with DAD and MS detectors was used to quantify the metabolites. For the first time, oleanolic and ursolic acids were quantified in the intractum (16.01 ± 1.3 and 2.21 ± 0.17 µg/g of oleanolic and ursolic acids, respectively). Regarding polyphenols, chlorogenic acid (0.92 mg/g of dried extract), caffeic acid (0.43 mg/g), dicaffeoylquinic acids (in total: 1.27 mg/g), and an unidentified caffeic acid ester (0.81 mg/g) were identified. The results in Balb/c mice revealed that the intractum does not cause significant variations in red blood cells parameters. In turn, a significant decrease in the total number of leukocytes was observed (5.8 × 103 µL), with a percentage increase in lymphocytes among the groups (80.2, 81.8, and 82.6). The ability of the intractum to decrease alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels may indicate its anti-inflammatory activity. Our observations justify that the fruits of E. senticosus are safe in the doses used and do not cause significant changes in the activity of the liver enzymes or in blood parameters.

Transcriptomic and Metabolomic Analysis Reveals the Potential Roles of Polyphenols and Flavonoids in Response to Sunburn Stress in Chinese Olive (Canarium album)

Sunburn stress is one of the main environmental stress factors that seriously affects the fruit development and quality of Chinese olive, a tropical and subtropical fruit in south China. Therefore, the understanding of the changes in physiological, biochemical, metabolic, and gene expression in response to sunburn stress is of great significance for the industry and breeding of Chinese olive. In this study, the different stress degrees of Chinese olive fruits, including serious sunburn injury (SSI), mild sunburn injury (MSI), and ordinary (control check, CK) samples, were used to identify the physiological and biochemical changes and explore the differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) by using transcriptomics and metabolomics. Compared with CK, the phenotypes, antioxidant capacity, and antioxidant-related enzyme activities of sunburn stress samples changed significantly. Based on DEG-based KEGG metabolic pathway analysis of transcriptomics, the polyphenol and flavonoid-related pathways, including phenylpropanoid biosynthesis, sesquiterpenoid, and triterpenoid biosynthesis, monoterpene biosynthesis, carotenoid biosynthesis, isoflavonoid biosynthesis, flavonoid biosynthesis, were enriched under sunburn stress of Chinese olive. Meanwhile, 33 differentially accumulated polyphenols and 99 differentially accumulated flavonoids were identified using metabolomics. According to the integration of transcriptome and metabolome, 15 and 8 DEGs were predicted to regulate polyphenol and flavonoid biosynthesis in Chinese olive, including 4-coumarate-CoA ligase (4CL), cinnamoyl-CoA reductase (CCR), cinnamoyl-alcohol dehydrogenase (CAD), chalcone synthase (CHS), flavanone-3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), and anthocyanidin synthase (ANS). Additionally, the content of total polyphenols and flavonoids was found to be significantly increased in MSI and SSI samples compared with CK. Our research suggested that the sunburn stress probably activates the transcription of the structural genes involved in polyphenol and flavonoid biosynthesis in Chinese olive fruits to affect the antioxidant capacity and increase the accumulation of polyphenols and flavonoids, thereby responding to this abiotic stress.

RBOH-dependent signaling is involved in He-Ne laser-induced salt tolerance and production of rosmarinic acid and carnosol in Salvia officinalis

BACKGROUND

In the past two decades, the impacts of Helium-Neon (He-Ne) laser on stress resistance and secondary metabolism in plants have been studied, but the signaling pathway which by laser regulates this process remains unclear. Therefore, the current study sought to explore the role of RBOH-dependent signaling in He-Ne laser-induced salt tolerance and elicitation of secondary metabolism in Salvia officinalis. Seeds were primed with He-Ne laser (6 J cm- 2) and peroxide hydrogen (H2O2, 5 mM) and 15-old-day plants were exposed to two salinity levels (0, 75 mM NaCl).

RESULTS

Salt stress reduced growth parameters, chlorophyll content and relative water content (RWC) and increased malodialdehyde (MDA) and H2O2 contents in leaves of 45-old-day plants. After 48 h of salt exposure, higher transcription levels of RBOH (encoding NADPH oxidase), PAL (phenylalanine ammonia-lyase), and RAS (rosmarinic acid synthase) were recorded in leaves of plants grown from seeds primed with He-Ne laser and/or H2O2. Despite laser up-regulated RBOH gene in the early hours of exposing to salinity, H2O2 and MDA contents were lower in leaves of these plants after 30 days. Seed pretreatment with He-Ne laser and/or H2O2 augmented the accumulation of anthocyanins, total phenol, carnasol, and rosmarinic acid and increased total antioxidant capacity under non-saline and more extensively at saline conditions. Indeed, these treatments improved RWC, and K+/Na+ ratio, enhanced the activities of superoxide dismutase and ascorbate peroxidase and proline accumulation, and significantly decreased membrane injury and H2O2 content in leaves of 45-old-day plants under salt stress. However, applying diphenylene iodonium (DPI as an inhibitor of NADPH oxidase) and N, N-dimethyl thiourea (DMTU as a H2O2 scavenger) after laser priming reversed the aforementioned effects which in turn resulted in the loss of laser-induced salt tolerance and secondary metabolism.

CONCLUSIONS

These findings for the first time deciphered that laser can induce a transient RBOH-dependent H2O2 burst, which might act as a downstream signal to promote secondary metabolism and salt stress alleviation in S. officinalis plants.

Comprehensive analysis of transcriptomics and metabolomics provides insights into the mechanism by plant growth regulators affect the quality of jujube (Ziziphus jujuba Mill.) fruit

A comprehensively analysis of the transcriptomics and metabolomics was conducted to investigate the mechanism of plant growth regulators on the quality of jujube fruit. After the application of plant growth regulators, a total of 3097 differentially expressed genes (DEGs) were identified, which were mainly annotated in 123 pathways such as flavonoid biosynthesis, metabolism of alanine, aspartate, and glutamate. In addition, 1091 differential expressed metabolites (DEMs), including 519 up-regulated and 572 down-regulated metabolites, were significantly altered after application of plant growth regulators. DEGs and DEMs simultaneously annotated 69 metabolic pathways, including biosynthesis of phenylpropane, flavonoid, starch and sucrose. The key genes in flavonoid biosynthesis pathway were revealed, which may play an important role in plant growth regulator regulation quality of jujube fruit. Besides, the application of plant growth regulator during the jujube flowering period increased the contents of gibberellin and indole-3-acetic acid in leaves, and decreased the contents of abscisic acid. The results may help to reveal the metabolic network and molecular mechanism of plant growth regulators in jujube fruit.

Tolerance Mechanisms and Removal Efficiency of Chlorella pyrenoidosa in Treating 3-Fluorophenol Pollution

This study investigates the growth tolerance mechanisms of Chlorella pyrenoidosa to 3-fluorophenol and its removal efficiency by algal cells. Our results indicate that C. pyrenoidosa can tolerate up to 100 mg/L of 3-fluorophenol, exhibiting a significant hormesis effect characterized by initial inhibition followed by promotion of growth. In C. pyrenoidosa cells, the activities of superoxide dismutase (SOD) and catalase (CAT), as well as the levels of malondialdehyde (MDA) and reactive oxygen species (ROS), were higher than or comparable to the control group. Metabolic analysis revealed that the 3-fluorophenol treatment activated pathways, such as glycerol phospholipid metabolism, autophagy, glycosylphosphatidylinositol (GPI)-anchored protein biosynthesis, and phenylpropanoid biosynthesis, contributed to the stabilization of cell membrane structures and enhanced cell repair capacity. After 240 h of treatment, over 50% of 3-fluorophenol was removed by algal cells, primarily through adsorption. Thus, C. pyrenoidosa shows potential as an effective biosorbent for the bioremediation of 3-fluorophenol.

β-Aminobutyric acid promotes stress tolerance, physiological adjustments, as well as broad epigenetic changes at DNA and RNA nucleobases in field elms (Ulmus minor)

BACKGROUND

β-Aminobutyric acid (BABA) has been successfully used to prime stress resistance in numerous plant species; however, its effectiveness in forest trees has been poorly explored thus far. This study aimed to investigate the influence of BABA on morphological, physiological, and epigenetic parameters in field elms under various growth conditions. Epigenetic changes were assessed in both DNA and RNA through the use of reversed-phase ultra-performance liquid chromatography (UPLC) coupled with sensitive mass spectrometry.

RESULTS

The presented results confirm the influence of BABA on the development, physiology, and stress tolerance in field elms. However, the most important findings are related to the broad epigenetic changes promoted by this amino acid, which involve both DNA and RNA. Our findings confirm, for the first time, that BABA influences not only well-known epigenetic markers in plants, such as 5-methylcytosine, but also several other non-canonical nucleobases, such as 5-hydroxymethyluracil, 5-formylcytosine, 5-hydroxymethylcytosine, N6-methyladenine, uracil (in DNA) and thymine (in RNA). The significant effect on the levels of N6-methyladenine, the main bacterial epigenetic marker, is particularly noteworthy. In this case, the question arises as to whether this effect is due to epigenetic changes in the microbiome, the plant genome, or both.

CONCLUSIONS

The plant phenotype is the result of complex interactions between the plant's DNA, the microbiome, and the environment. We propose that different types of epigenetic changes in the plant and microbiome may play important roles in the largely unknown memory process that enables plants to adapt faster to changing environmental conditions.

Molecular and physiological responses of two quinoa genotypes to drought stress

Quinoa is an important economic food crop. However, quinoa seedlings are susceptible to drought stress, and the molecular mechanism of drought tolerance remains unclear. In this study, we compared transcriptomic and physiological analyses of drought-tolerant (L1) and susceptible (HZ1) genotypes exposed to 20% PEG for 3 and 9 days at seedling stage. Compared with HZ1, drought stress had less damage to photosynthetic system, and the contents of SOD, POD and CAT were higher and the contents of H2O2 and O2 -were lower in L1 leaves. Based on the RNA-seq method, we identified 2423, 11856, 1138 and 3903 (HZ1-C3-VS-T3, HZ1-C9-vs-T9, L1-C3-vs-T3 and L1-C9-vs-T9) annotated DEGs. Go enrichment was shown in terms of Biological Process: DEGs involved in biological processes such as metabolic process, cellular process, and single-organism process were most abundant in all four comparison treatments. In Molecular Function: the molecular functions of catalytic activity, binding and transporter activity have the most DEGs in all four processes. Cellular Component: membrane, membrane part, and cell have the most DEGs in each of the four processes. These DEGs include AP2/ERF, MYB, bHLH, b-ZIP, WRKY, HD-ZIP, NAC, C3h and MADS, which encode transcription factors. In addition, the MAPK pathway, starch and sucrose metabolism, phenylpropanoid biosynthesis and plant hormone signal transduction were significantly induced under drought stress, among them, G-hydrolases-66, G-hydrolases-81, G-hydrolases-78, Su-synthase-02, Su-synthase-04, Su-synthase-06, BRI1-20 and bHLH17 were all downregulated at two drought stress points in two genotypes, PP2C01, PP2C03, PP2C05-PP2C07, PP2C10, F-box01 and F-box02 were upregulated at two drought stress points in two genotypes. These results agree with the physiological responses and RNA-seq results. Collectively, these findings may lead to a better understanding of drought tolerance, and some of the important DEGs detected in this study could be targeted for future research. And our results will provide a comprehensive basis for the molecular network that mediates drought tolerance in quinoa seedlings and promote the breeding of drought-resistant quinoa varieties.

Botrytis cinerea causes different plant responses in grape (Vitis vinifera) berries during noble and grey rot: diverse metabolism versus simple defence

The complexity of the interaction between the necrotrophic pathogen Botrytis cinerea and grape berries (Vitis vinifera spp.) can result in the formation of either the preferred noble rot (NR) or the loss-making grey rot (GR), depending on the prevailing climatic conditions. In this study, we focus on the functional gene set of V. vinifera by performing multidimensional scaling followed by differential expression and enrichment analyses. The aim of this study is to identify the differences in gene expression between grape berries in the phases of grey rot, noble rot, and developing rot (DR, in its early stages) phases. The grapevine transcriptome at the NR phase was found to exhibit significant differences from that at the DR and GR stages, which displayed strong similarities. Similarly, several plant defence-related pathways, including plant-pathogen interactions as hypersensitive plant responses were found to be enriched. The results of the analyses identified a potential plant stress response pathway (SGT1 activated hypersensitive response) that was found to be upregulated in the GR berry but downregulated in the NR berry. The study revealed a decrease in defence-related in V. vinifera genes during the NR stages, with a high degree of variability in functions, particularly in enriched pathways. This indicates that the plant is not actively defending itself against Botrytis cinerea, which is otherwise present on its surface with high biomass. This discrepancy underscores the notion that during the NR phase, the grapevine and the pathogenic fungi interact in a state of equilibrium. Conversely the initial stages of botrytis infection manifest as a virulent fungus-plant interaction, irrespective of whether the outcome is grey or noble rot.

Integrated physiological, biochemical, and transcriptomic analyses of Bruguiera gymnorhiza leaves under long-term copper stress: Stomatal size, wax crystals and composition

Copper (Cu) is a necessary mineral nutrient for plant growth and development and is involved in several morphological, physiological, and biochemical processes; however, high concentrations of Cu can negatively impact these processes. The role of stomata in responding to various biotic and abiotic stimuli has not been studied in Bruguiera gymnorhiza, particularly in terms of their coordinated interactions at the molecular, physiological, and biochemical levels. Moreover, numerous plants employ strategies such as the presence of thick waxy cuticles on their leaf epidermis and the closing of stomata to reduce water loss. Thus, this study investigates the accumulation of Cu in B. gymnorhiza and its effect on leaf morphology and the molecular response under different Cu treatments (0, 200, and 400 mg L⁻¹, Cu0, Cu200, and Cu400, respectively) during a two years stress period. The results show that Cu stress affected accumulation and transport, increased the activities of peroxidase and ascorbate peroxidase, concentrations of soluble sugar, proline, and H2O2, and decreased the activity of catalase and content of malondialdehyde. Also, Cu-induced stress decreased the uptake of phosphorus and nitrogen and inhibited plant photosynthesis, which consequently led to reduced plant growth. Scanning electron microscopy combined with gas chromatography-mass spectrometry showed that B. gymnorhiza leaves had higher wax crystals and compositions under increased Cu stress, which forced the leaf's stomata to be closed. Also, the contents of alkanes, alcohols, primary alcohol levels (C26:0, C28:0, C30:0, and C32:0), n-Alkanes (C29 and C30), and other wax loads were significantly higher, while fatty acid (C12, C16, and C18) was lower in Cu200 and Cu400 compared to Cu0. Furthermore, the transcriptomic analyses revealed 1240 (771 up- and 469 downregulated), 1000 (723 up- and 277 down-regulated), and 1476 (808 up- and 668 downregulated) differentially expressed genes in Cu0 vs Cu200, Cu0 vs Cu400, and Cu200 vs Cu400, respectively. RNA-seq analyses showed that Cu mainly affected eight pathways, including photosynthesis, cutin, suberin, and wax biosynthesis. This study provides a reference for understanding mangrove response to heavy metal stress and developing novel management practices.

Omics analysis of 'Shine Muscat' grape grafted on different rootstocks in response to cadmium stress

Cadmium (Cd) is detrimental to grape growth, development, and fruit quality. Grafting is considered to be a useful method to improve plant adaptability to Cd stress in grape production. However, little information is available on how Cd stress affects grafted grapes. In this study, the effects of Cd on Shine Muscat grapes (Vitis vinifera L. cv. 'Shine Muscat') were studied under different "Cd treatments" concentrations (0, 0.2, 0.4, 0.8, 1.6, 3.2 mg kg-1) and "rootstock treatments" (SO4, 5BB, and 3309C). The results showed that low levels of Cd had hormesis effect and activated the grape antioxidant system to eliminate the ROS induced by Cd stress. The antioxidant capacity of the SM/3309C rootstock combination was stronger than that of the other two groups under low-concentration Cd stress. Moreover, the rootstock effectively sequestered a substantial amount of Cd, consequently mitigating the upward translocation of Cd to the aboveground portions. Transcriptomic and metabolomic analysis revealed several important pathways enriched in ABC transporters, flavonoid biosynthesis, Plant hormone signal transduction, phenylpropanoid biosynthesis, and glutathione metabolism under Cd stress. WGCNA analysis identified a hub gene, R2R3-MYB15, which could promote the expression of several genes (PAL, 4CL, CYP73A, ST, CHS, and COMT), and alleviate the damage caused by Cd toxicity. These findings might shed light on the mechanism of hormesis triggered by low Cd stress in grapes at the transcriptional and metabolic levels.