Deciphering the possible role of RNA-helicase genes mechanism in response to abiotic stresses in rapeseed (Brassica napus L.).

BACKGROUND: Plants mediate several defense mechanisms to withstand abiotic stresses. Several gene families respond to stress as well as multiple transcription factors to minimize abiotic stresses without minimizing their effects on performance potential. RNA helicase (RH) is one of the foremost critical gene families that can play an influential role in tolerating abiotic stresses in plants. However, little knowledge is present about this protein family in rapeseed (canola). Here, we performed a comprehensive survey analysis of the RH protein family in rapeseed (Brassica napus L.). RESULTS: A total of 133 BnRHs genes have been discovered in this study. By phylogenetic analysis, RHs genes were divided into one main group and a subgroup. Examination of the chromosomal position of the identified genes showed that most of the genes (27%) were located on chromosome 3. All 133 identified sequences contained the main DEXDC domain, the HELICC domain, and a number of sub-domains. The results of biological process studies showed that about 17% of the proteins acted as RHs, 22% as ATP binding, and 14% as mRNA binding. Each part of the conserved motifs, communication network, and three-dimensional structure of the proteins were examined separately. The results showed that the RWC in leaf tissue decreased with higher levels of drought stress and in both root and leaf tissues sodium concentration was increased upon increased levels of salt stress treatments. The proline content were found to be increased in leaf and root with the increased level of stress treatment. Finally, the expression patterns of eight selected RHs genes that have been exposed to drought, salinity, cold, heat and cadmium stresses were investigated by qPCR. The results showed the effect of genes under stress. Examination of gene expression in the Hayola #4815 cultivar showed that all primers except primer #79 had less expression in both leaves and roots than the control level. CONCLUSIONS: New finding from the study have been presented new insights for better understanding the function and possible mechanism of RH in response to abiotic stress in rapeseed.

Coumarin Interferes with Polar Auxin Transport Altering Microtubule Cortical Array Organization in Arabidopsis thaliana (L.) Heynh. Root Apical Meristem.

Coumarin is a phytotoxic natural compound able to affect plant growth and development. Previous studies have demonstrated that this molecule at low concentrations (100 µM) can reduce primary root growth and stimulate lateral root formation, suggesting an auxin-like activity. In the present study, we evaluated coumarin's effects (used at lateral root-stimulating concentrations) on the root apical meristem and polar auxin transport to identify its potential mode of action through a confocal microscopy approach. To achieve this goal, we used several Arabidopsis thaliana GFP transgenic lines (for polar auxin transport evaluation), immunolabeling techniques (for imaging cortical microtubules), and GC-MS analysis (for auxin quantification). The results highlighted that coumarin induced cyclin B accumulation, which altered the microtubule cortical array organization and, consequently, the root apical meristem architecture. Such alterations reduced the basipetal transport of auxin to the apical root apical meristem, inducing its accumulation in the maturation zone and stimulating lateral root formation.

Yield parameters and antioxidant compounds of tomato fruit: the role of plant defence inducers with or without Cucumber mosaic virus infection.

BACKGROUND: The production of fruit and vegetables rich in health-promoting components in an eco-friendly context represents the winning answer to the world population demand for food. In this study, the effects of different treatments on the yield and fruit chemical characteristics of tomato (Solanum lycopersicum L.) are reported. The treatments included three inducers of plant defence responses (chitosan, Trichoderma harzianum T-22 and Bacillus subtilis QST713) applied alone or before Cucumber mosaic virus infection. Fruit production and antioxidant compounds were investigated by ultrahigh-performance liquid chromatography (UHPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS: Compared to control fruit harvested from untreated and healthy plants, treatment with QST713 increased the fruit number. Furthermore, plant treatments with T22, QST713 and chitosan alone enhanced fruit carotenoids (lutein and ß-carotene), ascorbic acid and phenolic acids (caffeoyl glucoside and p-coumaroyl glucoside). In parallel, compared to fruit harvested from only CMV-infected plants, treatments with T22, QST713 and chitosan before CMV enhanced fruit ascorbic acid and flavonoids (quercetin 3-O-xylosyl-rutinoside and rutin). CONCLUSION: Antioxidant compounds of tomato fruit can increase with the application of the plant defence inducers, thus protecting both the consumer and plant health. © 2019 Society of Chemical Industry.

Environmental factors influencing landfill gas biofiltration: Lab scale study on methanotrophic bacteria growth.

The post-management of landfills represents an important challenge for landfill gas treatment. Traditional systems (energy recovery, flares, etc.) present technical problems in treating flow with low methane (CH4) concentrations. The objective of this study was to isolate methanotrophic bacteria from a field-scale biofilter in order to study the bacteria in laboratories and evaluate the environmental factors that mostly influence Microbial Aerobic Methane Oxidation (MAMO). The soil considered was sampled from the biofilter located in the landfill of Venosa (Basilicata Region, Italy) and it was mainly composed of wood chips and compost. The results showed that methanotrophic microorganisms are mainly characterized by a slow growth and a significant sensitivity to CH4 levels. Temperature and nitrogen (N) also have a very important role on their development. On the basis of the results, biofilters for biological CH4 oxidation can be considered a viable alternative to mitigate CH4 emissions from landfills.

Anti-inflammatory and antioxidant activity of polyphenolic extracts from Lactuca sativa (var. Maravilla de Verano) under different farming methods.

BACKGROUND: Besides their nutritional value, vegetables are a source of health-promoting compounds, such as polyphenols, and their content can be influenced by the particular farming method. In this study polyphenolic extracts from Lactuca sativa (var. Maravilla de verano) plants cultivated with different farming methods were chemically characterised and tested in vitro and ex vivo inflammation models. RESULTS: The tested extacts (250-2.5 µg mL(-1) ) were able to reduce both the inflammatory and oxidative stress in LPS-stimulated J774A.1 murine monocyte macrophage cells, by lowering the release of nitric oxide (NO) and reactive oxygen species (ROS) and promoting nuclear translocation of nuclear factor (erythroid-derived 2)-like 2; (Nrf2) and nuclear factor-κB (NF-κB). In this regard, quantitative profiles revealed different amounts of polyphenols, in particular quercetin levels were higher in plants under mineral fertilised treatment. Those extract showed an enhanced anti-inflammatory and antioxidant activity. CONCLUSION: Our data showed the anti-inflammatory and antioxidant potential of Maravilla de Verano polyphenolic extracts. The effect of farming methods on polyphenolic levels was highlighted. The higher reduction of inflammatory mediators release in extracts from plants cultivated under mineral fertilisation treatment was correlated to the higher amount of quercetin. These results can be useful for both nutraceutical or agronomic purposes. © 2016 Society of Chemical Industry.

Ascorbate Peroxidase and Catalase Activities and Their Genetic Regulation in Plants Subjected to Drought and Salinity Stresses.

Hydrogen peroxide (H2O2), an important relatively stable non-radical reactive oxygen species (ROS) is produced by normal aerobic metabolism in plants. At low concentrations, H2O2 acts as a signal molecule involved in the regulation of specific biological/physiological processes (photosynthetic functions, cell cycle, growth and development, plant responses to biotic and abiotic stresses). Oxidative stress and eventual cell death in plants can be caused by excess H2O2 accumulation. Since stress factors provoke enhanced production of H2O2 in plants, severe damage to biomolecules can be possible due to elevated and non-metabolized cellular H2O2. Plants are endowed with H2O2-metabolizing enzymes such as catalases (CAT), ascorbate peroxidases (APX), some peroxiredoxins, glutathione/thioredoxin peroxidases, and glutathione sulfo-transferases. However, the most notably distinguished enzymes are CAT and APX since the former mainly occurs in peroxisomes and does not require a reductant for catalyzing a dismutation reaction. In particular, APX has a higher affinity for H2O2 and reduces it to H2O in chloroplasts, cytosol, mitochondria and peroxisomes, as well as in the apoplastic space, utilizing ascorbate as specific electron donor. Based on recent reports, this review highlights the role of H2O2 in plants experiencing water deficit and salinity and synthesizes major outcomes of studies on CAT and APX activity and genetic regulation in drought- and salt-stressed plants.

Appraisal of the Role of Gaseous Signaling Molecules in Thermo-Tolerance Mechanisms in Plants.

A significant threat to the ongoing rise in temperature caused by global warming. Plants have many stress-resistance mechanisms, which is responsible for maintaining plant homeostasis. Abiotic stresses largely increase gaseous molecules' synthesis in plants. The study of gaseous signaling molecules has gained attention in recent years. The role of gaseous molecules, such as nitric oxide (NO), hydrogen sulfide (H2S), carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), and ethylene, in plants under temperature high-temperature stress are discussed in the current review. Recent studies revealed the critical function that gaseous molecules play in controlling plant growth and development and their ability to respond to various abiotic stresses. Here, we provide a thorough overview of current advancements that prevent heat stress-related plant damage via gaseous molecules. We also explored and discussed the interaction of gaseous molecules. In addition, we provided an overview of the role played by gaseous molecules in high-temperature stress responses, along with a discussion of the knowledge gaps and how this may affect the development of high-temperature-resistant plant species.

Correlation between hormonal homeostasis and morphogenic responses in Arabidopsis thaliana seedlings growing in a Cd/Cu/Zn multi-pollution context.

To date, almost no information is available in roots and shoots of the model plant Arabidopsis thaliana about the hierarchic relationship between metal accumulation, phytohormone levels, and glutathione/phytochelatin content, and how this relation affects root development. For this purpose, specific concentrations of cadmium, copper and zinc, alone or in triple combination, were supplied for 12 days to in vitro growing seedlings. The accumulation of these metals was measured in roots and shoots, and a significant competition in metal uptake was observed. Microscopic analyses revealed that root morphology was affected by metal exposure, and that the levels of trans-zeatin riboside, dihydrozeatin riboside, indole-3-acetic acid and the auxin/cytokinin ratio varied accordingly. By contrast, under metal treatments, minor modifications in gibberellic acid and abscisic acid levels occurred. Real-time polymerase chain reaction analysis of some genes involved in auxin and cytokinin synthesis (e.g. AtNIT in roots and AtIPT in shoots) showed on average a metal up-regulated transcription. The production of thiol-peptides was induced by all the metals, alone or in combination, and the expression of the genes involved in thiol-peptide synthesis (AtGSH1, AtGSH2, AtPCS1 and AtPCS2) was not stimulated by the metals, suggesting a full post-transcriptional control. Results show that the Cd/Cu/Zn-induced changes in root morphology are caused by a hormonal unbalance, mainly governed by the auxin/cytokinin ratio.

Auxin and cytokinin metabolism and root morphological modifications in Arabidopsis thaliana seedlings infected with Cucumber mosaic virus (CMV) or exposed to cadmium.

Arabidopsis thaliana L. is a model plant but little information is available about morphological root changes as part of a phytohormonal common response against both biotic and abiotic stressors. For this purpose, two-week-old Arabidopsis seedlings were treated with 10 µM CdSO4 or infected with CMV. After 12 days the entire aerial parts and the root system were analyzed, and the presence of CMV or the accumulation of Cd were detected. Microscopic analysis revealed that both CMV and Cd influenced root morphology by a marked development in the length of root hairs and an intense root branching if compared to controls. Among the three treatments, Cd-treated seedlings showed a shorter root axis length and doubled their lateral root diameter, while the lateral roots of CMV-infected seedlings were the longest. The root growth patterns were accompanied by significant changes in the levels of indole-3-acetic acid, trans-zeatin riboside, dihydrozeatin riboside, as a probable consequence of the regulation of some genes involved in their biosynthesis/degradation. The opposite role on root development played by the phythormones studied is discussed in detail. The results obtained could provide insights into novel strategies for plant defense against pathogens and plant protection against pollutants.

Application of Bio-Fertilizers Improves Forage Quantity and Quality of Sorghum (Sorghum bicolor L.) Intercropped with Soybean (Glycine max L.).

In recent years, application of bio-fertilizers (BFs) in intercropping systems has become known as one of the main sustainable and eco-friendly strategies for improving the quantity and quality of forage crops. In order to evaluate the forage quantity and quality of sorghum intercropped with soybean, a two-year field experiment was carried out as factorial based on a randomized complete blocks design (RCBD) with three replications. The first factor was different cropping patterns including soybean monocultures with densities of 40 and 50 plants m-2 (G40 and G50), sorghum monocultures with densities of 10 and 15 plants m-2 (S10 and S15) and intercropping of two plants with the mentioned densities. The second factor was non-application (control) and application of bio-fertilizers. The results demonstrated that the highest dry forage yield of sorghum (21.22 t ha-1) was obtained in monoculture conditions with density of 15 plants m-2 and inoculation with bio-fertilizer (S15+BF). The maximum crude protein (CP = 149.6 g kg-1 DM), ash (113.2 g kg-1 DM), water soluble carbohydrates (WSC = 251.16 g kg-1 DM), dry matter intake (DMI = 26.83 g kg-1 of body weight), digestible dry matter (DDM = 668.01 g kg-1 DM), total digestible nutrients (TDN = 680.42 g kg-1 DM), relative feed value (RFV = 142.98%) and net energy for lactation (NEL = 1.625 Mcal kg-1) were observed in the intercropping of S10G50 inoculated with BF. Interestingly, application of bio-fertilizers enhanced the content of CP, ash, WSC, DMI, DDM, TDN, RFV and NEL by 7.5, 8, 11.7, 3.6, 2.3, 12.3, 5.9 and 3.5% when compared with the control (non-application of bio-fertilizers). In all intercropping patterns, the total land equivalent ratio (LER) value was greater than one, representing the advantage of these cropping patterns in comparison with sorghum monoculture. The highest total LER was recorded in the intercropping of S15G40 and S10G50 following application of BF. Additionally, the highest monetary advantage index (MAI) was calculated in the intercropping of S15G40+BF. Generally, it can be concluded that the intercropping of S10G50 along with bio-fertilizer inoculation could be suggested as an eco-friendly strategy for improving the forage quantity and quality under low-input conditions.

Brassinosteroid modulates ethylene synthesis and antioxidant metabolism to protect rice (Oryza sativa) against heat stress-induced inhibition of source‒sink capacity and photosynthetic and growth attributes.

This study presents an exploration of the efficacy of brassinosteroids (BRs) and ethylene in mediating heat stress tolerance in rice (Oryza sativa). Heat is one of the major abiotic factors that prominently deteriorates rice production by influencing photosynthetic efficiency, source‒sink capacity, and growth traits. The application of BR (0.5 mM) and ethylene (200 µl l-1) either individually and/or in combination was found to alleviate heat stress-induced toxicity by significantly improving photosynthesis, source‒sink capacity and defense systems; additionally, it reduced the levels of oxidative stress markers and ethylene formation. The study revealed the positive influence of BR in promoting plant growth responses under heat stress through its interplay with ethylene biosynthesis and enhanced plant defense systems. Interestingly, treatment with the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG) substantiated that BR application to heat-stressed rice plants enhanced ethylene-dependent pathways to counteract the underlying adversities. Thus, BR action was found to be mediated by ethylene to promote heat tolerance in rice. The present study sheds light on the potential tolerance mechanisms which can ensure rice sustainability under heat stress conditions.

Earthworm-Driven Changes in Soil Chemico-Physical Properties, Soil Bacterial Microbiota, Tree/Tea Litter Decomposition, and Plant Growth in a Mesocosm Experiment with Two Plant Species.

Earthworms and soil microorganisms contribute to soil health, quality, and fertility, but their importance in agricultural soils is often underestimated. This study aims at examining whether and to what extent the presence of earthworms (Eisenia sp.) affected the (a) soil bacterial community composition, (b) litter decomposition, and (c) plant growth (Brassica oleracea L., broccoli; Vicia faba L., faba bean). We performed a mesocosm experiment in which plants were grown outdoors for four months with or without earthworms. Soil bacterial community structure was evaluated by a 16S rRNA-based metabarcoding approach. Litter decomposition rates were determined by using the tea bag index (TBI) and litter bags (olive residues). Earthworm numbers almost doubled throughout the experimental period. Independently of the plant species, earthworm presence had a significant impact on the structure of soil bacterial community, in terms of enhanced α- and ß-diversity (especially that of Proteobacteria, Bacteroidota, Myxococcota, and Verrucomicrobia) and increased 16S rRNA gene abundance (+89% in broccoli and +223% in faba bean). Microbial decomposition (TBI) was enhanced in the treatments with earthworms, and showed a significantly higher decomposition rate constant (kTBI) and a lower stabilization factor (STBI), whereas decomposition in the litter bags (dlitter) increased by about 6% in broccoli and 5% in faba bean. Earthworms significantly enhanced root growth (in terms of total length and fresh weight) of both plant species. Our results show the strong influence of earthworms and crop identity in shaping soil chemico-physical properties, soil bacterial community, litter decomposition and plant growth. These findings could be used for developing nature-based solutions that ensure the long-term biological sustainability of soil agro- and natural ecosystems.

Toxic effects of four sulphonylureas herbicides on soil microbial biomass.

The effect of four triazinyl-sulfonylurea herbicides (cinosulfuron, prosulfuron, thifensulfuron methyl, triasulfuron) on soil microbial biomass, soil respiration, metabolic activity, metabolic quotient, and some enzymatic activities (acid and alkaline phosphatase, ß-glucosidase, arylsulphatase, and fluorescein diacetate hydrolysis) were monitored under controlled conditions over 30 days. The herbicides were applied at the normal field dose (FD) and at ten-fold (10 FD) the field dose, in order to mimic a long term toxic effect. The measured soil microbial parameters showed that the FD had slight effects on soil microflora, while at 10 FD the tested herbicides exerted a stronger detrimental effect on soil microbial biomass and its biochemical activities.

Subtoxic levels of some heavy metals cause differential root-shoot structure, morphology and auxins levels in Arabidopsis thaliana.

Contamination of soil by heavy metals severely affects plant growth and causes soil pollution. While effects on plant growth have been investigated for metals taken individually or in groups, less is known about their comparative effects. In this study Arabidopsis thaliana seedlings were grown for 14 days in Petri dishes containing medium contaminated by six common heavy metals (Hg, Cd, Pb, Cu, Ni and Zn), at the minimum concentrations defined as toxic by the most recent EU legislation on contamination of agricultural soils. (a) Root structure and morphology, (b) metal composition and translocation, and (c) the levels of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) were analyzed. Metals accumulated more in roots than in shoots, with concentrations that differed by several orders of magnitude depending on the metal: Cd (ca. 700 × and ca. 450 × in roots and shoots, respectively), Hg (150 × , 80 × ), Ni (50 × , 20 × ), Cu (48 × , 20 × ), Zn (23 × , 6 × ), and Pb (9 × , 4 × ). Responses were significant for at least nine of the ten root parameters (with the exception of Hg), and five of the six shoot parameters (with the exception of Zn). Cu and Zn induced respectively the strongest responses in root hormonal (up to ca. 240% the control values for IBA, 190% for IAA) and structural parameters (up to 210% for main root length, 330% for total lateral root length, 220% for number of root tips, 600% for total root surface, and from 2.5° to 26.0° of root growth angle). Regarding the shoots, the largest changes occurred for shoot height (down to 60% for Ni), rosette diameter (down to 45% for Hg), leaf number (up to 230% for Zn) and IBA (up to 240% for Pb and Cu). A microscope analysis revealed that shape and conformation of root hairs were strongly inhibited after Cd exposure, and enhanced under Hg and Pb. The results could have positive applications such as for defining toxicity thresholds (in phytoremediation) and acceptable concentration levels (for policies) for some of the most common heavy metals in agricultural soils.

Nitric Oxide and Abscisic Acid Mediate Heat Stress Tolerance through Regulation of Osmolytes and Antioxidants to Protect Photosynthesis and Growth in Wheat Plants.

Nitric oxide (NO) and abscisic acid (ABA) play a significant role to combat abiotic stress. Application of 100 µM sodium nitroprusside (SNP, NO donor) or ABA alleviated heat stress effects on photosynthesis and growth of wheat (Triticum aestivum L.) plants exposed to 40 °C for 6 h every day for 15 days. We have shown that ABA and NO synergistically interact to reduce the heat stress effects on photosynthesis and growth via reducing the content of H2O2 and thiobarbituric acid reactive substances (TBARS), as well as maximizing osmolytes production and the activity and expression of antioxidant enzymes. The inhibition of NO and ABA using c-PTIO (2-4 carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) and fluridone (Flu), respectively, reduced the osmolyte and antioxidant metabolism and heat stress tolerance. The inhibition of NO significantly reduced the ABA-induced osmolytes and antioxidant metabolism, exhibiting that the function of ABA in the alleviation of heat stress was NO dependent and can be enhanced with NO supplementation.Thus, regulating the activity and expression of antioxidant enzymes together with osmolytes production could act as a possible strategy for heat tolerance.

Carbon isotope discrimination and water use efficiency in interspecific Prunus hybrids subjected to drought stress.

In C3 plants, carbon isotope composition (δ13C) is influenced by isotopic effects during diffusion from the atmosphere to the chloroplasts and carboxylation reactions. This work aimed to demonstrate if δ13C of leaf soluble carbohydrates (δ13Cleaves) and of dry matter from new-growth shoots (δ13Cshoots) of Prunus plants subjected to a period of water deficit was related to water use efficiency (WUE). For this purpose, three interspecific Prunus hybrids rootstocks (6-5, 7-7 and G × N) were gradually subjected to drought and then rewatered. Soil water content (SWC) decreased from 26.1 to 9.4% after 70 days of water shortage, when plants reached values of predawn leaf water potential (LWP) ranging from -3.12 to -4.00 MPa. Gas exchange, particularly net photosynthetic and transpiration rates, differed among the three hybrids, leading to different values of WUE. After 70 days of drought, a significant δ13C increase of 5.86, 4.28 and 4.99‰ was observed in 6-5, 7-7 and G × N, respectively. Significant correlations between δ13C and other parameters (substomatal CO2/atmospheric CO2 ratio, stomatal conductance and stem water potential) were found in all hybrids. The rewatering phase caused a recovery of the physiological status of the plants. The isotope composition of δ13Cshoots was correlated with the average WUE measured during the whole experiment. δ13Cleaves and δ13Cshoots were positively related (r = 0.87; p < 0.001). The isotopic signature was a reliable screening tool to identify Prunus genotypes tolerant to drought stress. The results suggest the possibility of using δ13C as an integrated indicator of level of drought stress in plants subjected to prolonged stress conditions.

Ethylene Signaling under Stressful Environments: Analyzing Collaborative Knowledge.

Ethylene is a gaseous plant growth hormone that regulates various plant developmental processes, ranging from seed germination to senescence. The mechanisms underlying ethylene biosynthesis and signaling involve multistep mechanisms representing different control levels to regulate its production and response. Ethylene is an established phytohormone that displays various signaling processes under environmental stress in plants. Such environmental stresses trigger ethylene biosynthesis/action, which influences the growth and development of plants and opens new windows for future crop improvement. This review summarizes the current understanding of how environmental stress influences plants' ethylene biosynthesis, signaling, and response. The review focuses on (a) ethylene biosynthesis and signaling in plants, (b) the influence of environmental stress on ethylene biosynthesis, (c) regulation of ethylene signaling for stress acclimation, (d) potential mechanisms underlying the ethylene-mediated stress tolerance in plants, and (e) summarizing ethylene formation under stress and its mechanism of action.

Nitric Oxide and Salicylic Acid Regulate Glutathione and Ethylene Production to Enhance Heat Stress Acclimation in Wheat Involving Sulfur Assimilation.

Phytohormones have a role in stress adaptation. The major mechanism underlying the role of exogenously-sourced nitric oxide (NO; as sodium nitroprusside, SNP: 50.0 µM) and salicylic acid (SA; 0.5 mM) in the presence of 2.0 mM SO4-2 was assessed in heat stress (HS; 40 °C for 6 h daily for 15 days) tolerance in wheat (Triticum aestivum L. cv. HD-3226). The cultivar HD-3226 possessed high photosynthetic sulfur use efficiency (p-SUE) among the six cultivars screened. Plants grown under HS exhibited an increased content of reactive oxygen species (ROS; including superoxide radical and hydrogen peroxide) and extent of lipid peroxidation with a consequent reduction in photosynthesis and growth. However, both NO and SA were found to be protective against HS via enhanced S assimilation. Their application reduced oxidative stress and increased the activity of antioxidant enzymes. NO or SA supplementation along with S under HS recovered the losses and improved photosynthesis and growth. The use of SA inhibitor (2-aminoindane-2-phosphonic acid; AIP) and NO scavenger (cPTIO) confirmed that the mitigating effects of SA and NO involved induction in S assimilation.

Anthocyanin composition and extractability in berry skin and wine of Vitis vinifera L. cv. Aglianico.

BACKGROUND: The present article reports the anthocyanin content in the berry skin and wine of the Italian red grape cultivar Aglianico (clone VCR11 grafted onto 1103 Paulsen), one of the most ancient vines and famous for its deep-red colour. Anthocyanins were extracted from frozen berry skin in an acidified methanol solution. The extraction mixtures, monitored for 120 h, were analysed by high-performance liquid chromatography. RESULTS: The extraction from berry skin of delphinidin, petunidin and malvidin appeared to be a time-independent process, whereas the concentration of peonidin increased linearly with time. Peonidin-O-acetyl-glucoside was transferred from skin more slowly than petunidin-O-acetyl-glucoside and malvidin-O-acetyl-glucoside. The anthocyanin composition of the resulting wine showed that the total anthocyanin content was about one-tenth of the corresponding berry skin content. The ratio acetyl/coumaroyl anthocyanins in the wine was sharply higher than the value in berry skin (0.85 and 0.10, respectively), indicating an enrichment of acetyl derivatives in the wine. CONCLUSION: Levels of single anthocyanins in wine were not always correlated with those detected in grapes, as they were affected by winemaking. The high values of some anthocyanins in Aglianico wine could ameliorate its quality, increasing the chromatic properties, aging stability and product acceptance.

Ethylene and Sulfur Coordinately Modulate the Antioxidant System and ABA Accumulation in Mustard Plants under Salt Stress.

This study explored the interactive effect of ethephon (2-chloroethyl phosphonic acid; an ethylene source) and sulfur (S) in regulating the antioxidant system and ABA content and in maintaining stomatal responses, chloroplast structure, and photosynthetic performance of mustard plants (Brassica juncea L. Czern.) grown under 100 mM NaCl stress. The treatment of ethephon (200 µL L-1) and S (200 mg S kg-1 soil) together markedly improved the activity of enzymatic and non-enzymatic components of the ascorbate-glutathione (AsA-GSH) cycle, resulting in declined oxidative stress through lesser content of sodium (Na+) ion and hydrogen peroxide (H2O2) in salt-stressed plants. These changes promoted the development of chloroplast thylakoids and photosynthetic performance under salt stress. Ethephon + S also reduced abscisic acid (ABA) accumulation in guard cell, leading to maximal stomatal conductance under salt stress. The inhibition of ethylene action by norbornadiene (NBD) in salt- plus non-stressed treated plants increased ABA and H2O2 contents, and reduced stomatal opening, suggesting the involvement of ethephon and S in regulating stomatal conductance. These findings suggest that ethephon and S modulate antioxidant system and ABA accumulation in guard cells, controlling stomatal conductance, and the structure and efficiency of the photosynthetic apparatus in plants under salt stress.