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King oyster mushroom Pleurotus eryngii is cultivated worldwide for culinary and to improve human health. However, the potential of some Mediterranean representatives of this species is still not evaluated. This work focuses on the study of polysaccharides from fruiting bodies of two Tunisian strains, P. eryngii var. elaeoselini and P. eryngii var. ferulae, and, for comparison, one deposited P. eryngii originated from Korea. Polysaccharides were successively extracted with hot water using microwave heating and 1 mol L -1 aqueous sodium hydroxide. The crude hot water extracts were purified by treating them with proteolytic enzymes, and the alkaline extracts were purified by re-dissolving with dimethyl sulphoxide. In both cases, a decrease or removal of proteins was detected. Glucans predominated in all these products; the insoluble parts also contained chitin. The purified hot water extracts contained glycogen, β-d-glucans and mannogalactan. Branching (1 → 3)(1 → 6)-β-d-glucan was the major polysaccharide in the alkali-soluble fractions, while (1 → 3)-α-d-glucan was only a minor component. The Tunisian strains demonstrated a higher proportion of water-soluble polysaccharides, compared to the alkaline soluble ones, and more β-d-glucan in the insoluble chitin-glucan complexes. Fruiting body proteins of these strains are more available for solubilisation and enzymatic or alkaline degradation and, thus, may have higher nutritional value than those of the reference strain. As a source of proteins or polysaccharides, the Tunisian endemic P. eryngii strains of this study are promising for the domestication and cultivation of fruiting bodies for gastronomic purposes in the North African region., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The use of natural dyes in several areas is regulated by current European and non-European legislation, due to various problems with synthetic dyes. The analysis revealed that the lichen studied: Xanthoria parietina has potential natural dye sources and provides bright colors for extraction solvents. Furthermore, dyed wool and toile fabric have good fastness properties in ammonia fermentation and boiling water, both with and without mordants. The sample dyes with Xanthoria parietina were characterized by several analytical techniques: high-performance liquid chromatography with diode array detection (HPLC-DAD) and electrospray ionization with tandem mass spectrometry (HPLC-ESI-Q-ToF). As compounds from Xanthoria parietina form a complex with mordants and tissues, it is impossible to identify the molecules responsible for coloring using chromatographic techniques. However, we have evaluated the dyeing power of their major molecule, parietin. To further confirm the coloring power of the isolated parietin molecule, we performed a dye test with pure parietin. Thus, CIALAB analyses have shown parietin is the molecule responsible for the coloring obtained by Xanthoria parietina. The utilization of parietin derived from lichens facilitates the development of sustainable dyes for textile coloring, presenting an environmentally friendly alternative to synthetic dyes while simultaneously enriching lichen biodiversity., (© 2023 Wiley-VHCA AG, Zurich, Switzerland.)

Main Conclusion: In Medicago sativa nodulated roots, NR-dependent NO production is involved in maintaining energy state, presumably through phytoglobin NO respiration, under both salinity and hypoxia stress. The response to low and average salinity stress and to a 5 day-long flooding period was analyzed in M. sativa nodulated roots. The two treatments result in a decrease in the biological nitrogen fixation capacity and the energy state (evaluated by the ATP/ADP ratio), and conversely in an increase nitric oxide (NO) production. Under salinity and hypoxia treatments, the use of either sodium tungstate, an inhibitor of nitrate reductase (NR), or carboxy-PTIO, a NO scavenger, results in a decrease in NO production and ATP/ADP ratio, meaning that NR-dependent NO production participates to the maintenance of the nodulated roots energy state.

This study, the first to assess the total phenolic, flavonoid, tannins, and proanthocyanidin content of the Tunisian lichen Diploschistes ocellatus, determined the antioxidant capacity in scavenging 2,2 diphenyl-1-picrylhydrazyl (DPPH), as well as the ferric-reducing and iron-chelating powers. The phenolic compound content of D. ocellatus was shown to be related to antioxidant activity. The highest phenolic and flavonoid contents of extracts were obtained with acetone (286.3 μg GAE/g DW and 3.24 μg CE/g DW, respectively), while the highest tannin and proanthocyanidin contents were obtained with methanol (5.5 μg TAE/g DW and 35.12 μg CE/g DW, respectively). The highest DPPH' scavenging capacity and iron-chelating power of extracts were obtained with methanol (concentration providing 50% inhibition [IC50] = 0.029 mg/mL and IC50 = 0.425 mg/mL, respectively), while acetone extracts showed a higher reducing power (IC50 = 0.118 mg/mL).

This study is, to our knowledge, the first to investigate the pharmacological importance of wild Tunisian mushrooms. Ethanolic extracts of 5 Tunisian mushrooms-Phellinus torulosus, Fomes fomentarius, Trametes versicolor, Pisolithus albus, and Fomitopsis pinicola-were collected from the Kroumirie Region (North Tunisia). The dry basidomes of mushrooms were extracted using ethanol and evaluated for total polyphenol, flavonoid, flavonol, tannin, proanthocyanidin, and anthocyanin content. In addition, their antioxidant activities were determined using 3 assays (testing 2,2-diphenyl-1-picrylhydrazyl [DPPH] radical scavenging, the reducing power of iron, and the iron-chelating power). Their antimicrobial activities were assessed against 8 bacterial species. The results revealed the presence of significant differences between the secondary metabolites and biological activities of the different tested extracts. In addition, significant correlations were observed between antioxidant activities and phenolic contents. Crude ethanol extracts prepared from basidomes of F. fomentarius and Ph. torulosus have higher total phenolic content and antioxidant activity per the DPPH and metal-chelating activity assays. The reducing power assay showed that the ethanolic extract of F. pinicola had the highest activity. Ethanolic extracts of the 5 mushrooms have antibacterial activity against the evaluated strains.

This study is the first to evaluate the potential of Calligonum azel Maire as a food ingredient. The plant materials flowers, leaves, stems and roots were analyzed by wet-chemical and instrumental methods for major and minor composition. The highest protein and sugar contents were recorded in the flowers (17.8% and 1.6% respectively), while the fat content was most abundant in the leaves (2.9%). Hexane extracts screened by gas chromatography (GC) for fatty acid composition showed 14 major compounds such as oleic acid, linoleic acid and palmitic acid, but also ω3 and ω6 unsaturated fatty acids. The essential oils extracted by hydrodistillation were screened by GC/MS and 31 compounds were identified including estragole, naphthalene, anethole, phytol and curcumene. The HPLC-DAD screening revealed that the methanolic extracts do not contain any pharmacologically active compound with adverse properties, but quercetin, hordenine and vanillin were abundant in the flowers, leaves and roots. Proton nuclear magnetic resonance ( 1 H NMR) spectroscopy showed that glucose, sucrose and fructose were abundant in acetone and methanol extracts, while urea and glycerol were abundant in the aqueous extracts. A sensory evaluation of the aqueous infusions showed properties of the flowers reminiscent of other herbal teas. In conclusion, our results corroborate the suitability of the traditionally described use of Calligonum azel Maire as food and feed. The further study of this plant as a sustainable nutritional ingredient appears to be worthwhile., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

This study is the first to investigate the chemical composition of barks essential oil (EO), secondary metabolites and biological activities of the MeOH and infusions extracts of seeds, leaves, barks and roots of Calligonum azel Maire (Polygonaceae) harvested from Tunisian desert. The gas chromatography/mass spectrometry (GC/MS) results showed the presence of fifty-four compounds in barks EO. The major components were: viridiflorol (14.6%), α-eudesmol (8.65%), trans-caryophyllene (6.72%), elemol (6.63%), β-eudesmol (6.21%). The obtained results showed that C. azel is a very rich plant in secondary metabolites. High contents in polyphenols, flavonoids and tannins were observed in both extracts of all studied organs. Significant differences were found between both extracts of the four organs. Thus, polyphenols and tannins were more abundant in leaves infusion extract, while, flavonoids showed a high level in barks extract. The antioxidant activity data demonstrated that all extracts showed strong antioxidant and radical scavenging activities. The MeOH extracts presented potential for antibacterial and antifungal activities against all tested microorganisms. The inhibition zones diameters and minimal inhibitrice concentration values were in the range of 9 - 15 mm and 2.5 - 20 μg/ml, respectively. This study demonstrated that C. azel can be regarded as an excellent plant source for natural antimicrobial agents., (© 2016 Wiley-VHCA AG, Zurich, Switzerland.)

Background: Arbuscular mycorrhizal (AM) fungi, which engage a mutualistic symbiosis with the roots of most plant species, have received much attention for their ability to alleviate heavy metal stress in plants, including cadmium (Cd). While the molecular bases of Cd tolerance displayed by mycorrhizal plants have been extensively analysed in roots, very little is known regarding the mechanisms by which legume aboveground organs can escape metal toxicity upon AM symbiosis. As a model system to address this question, we used Glomus irregulare-colonised Medicago truncatula plants, which were previously shown to accumulate and tolerate heavy metal in their shoots when grown in a substrate spiked with 2 mg Cd kg(-1)., Results: The measurement of three indicators for metal phytoextraction showed that shoots of mycorrhizal M. truncatula plants have a capacity for extracting Cd that is not related to an increase in root-to-shoot translocation rate, but to a high level of allocation plasticity. When analysing the photosynthetic performance in metal-treated mycorrhizal plants relative to those only Cd-supplied, it turned out that the presence of G. irregulare partially alleviated the negative effects of Cd on photosynthesis. To test the mechanisms by which shoots of Cd-treated mycorrhizal plants avoid metal toxicity, we performed a 2-DE/MALDI/TOF-based comparative proteomic analysis of the M. truncatula shoot responses upon mycorrhization and Cd exposure. Whereas the metal-responsive shoot proteins currently identified in non-mycorrhizal M. truncatula indicated that Cd impaired CO2 assimilation, the mycorrhiza-responsive shoot proteome was characterised by an increase in photosynthesis-related proteins coupled to a reduction in glugoneogenesis/glycolysis and antioxidant processes. By contrast, Cd was found to trigger the opposite response coupled the up-accumulation of molecular chaperones in shoot of mycorrhizal plants relative to those metal-free., Conclusion: Besides drawing a first picture of shoot proteome modifications upon AM symbiosis and/or heavy metal stress in legume plants, the current work argues for allocation plasticity as the main driving force for Cd extraction in aboveground tissues of M. truncatula upon mycorrhization. Additionally, according to the retrieved proteomic data, we propose that shoots of mycorrhizal legume plants escape Cd toxicity through a metabolic shift implying the glycolysis-mediated mobilization of defence mechanisms at the expense of the photosynthesis-dependent symbiotic sucrose sink.

To evaluate the genotypic variation of salt stress response in tomato, physiological analyses and a proteomic approach have been conducted in parallel on four contrasting tomato genotypes. After a 14 d period of salt stress in hydroponic conditions, the genotypes exhibited different responses in terms of plant growth, particularly root growth, foliar accumulation of Na(+), and foliar K/Na ratio. As a whole, Levovil appeared to be the most tolerant genotype while Cervil was the most sensitive one. Roma and Supermarmande exhibited intermediary behaviours. Among the 1300 protein spots reproducibly detected by two-dimensional electrophoresis, 90 exhibited significant abundance variations between samples and were submitted to mass spectrometry for identification. A common set of proteins (nine spots), up- or down-regulated by salt-stress whatever the genotype, was detected. But the impact of the tomato genotype on the proteome variations was much higher than the salt effect: 33 spots that were not variable with salt stress varied with the genotype. The remaining number of variable spots (48) exhibited combined effects of the genotype and the salt factors, putatively linked to the degrees of genotype tolerance. The carbon metabolism and energy-related proteins were mainly up-regulated by salt stress and exhibited most-tolerant versus most-sensitive abundance variations. Unexpectedly, some antioxidant and defence proteins were also down-regulated, while some proteins putatively involved in osmoprotectant synthesis and cell wall reinforcement were up-regulated by salt stress mainly in tolerant genotypes. The results showed the effect of 14 d stress on the tomato root proteome and underlined significant genotype differences, suggesting the importance of making use of genetic variability.

Nitric oxide (NO) is a signaling and defense molecule of major importance in living organisms. In the model legume Medicago truncatula, NO production has been detected in the nitrogen fixation zone of the nodule, but the systems responsible for its synthesis are yet unknown and its role in symbiosis is far from being elucidated. In this work, using pharmacological and genetic approaches, we explored the enzymatic source of NO production in M. truncatula-Sinorhizobium meliloti nodules under normoxic and hypoxic conditions. When transferred from normoxia to hypoxia, nodule NO production was rapidly increased, indicating that NO production capacity is present in functioning nodules and may be promptly up-regulated in response to decreased oxygen availability. Contrary to roots and leaves, nodule NO production was stimulated by nitrate and nitrite and inhibited by tungstate, a nitrate reductase inhibitor. Nodules obtained with either plant nitrate reductase RNA interference double knockdown (MtNR1/2) or bacterial nitrate reductase-deficient (napA) and nitrite reductase-deficient (nirK) mutants, or both, exhibited reduced nitrate or nitrite reductase activities and NO production levels. Moreover, NO production in nodules was found to be inhibited by electron transfer chain inhibitors, and nodule energy state (ATP-ADP ratio) was significantly reduced when nodules were incubated in the presence of tungstate. Our data indicate that both plant and bacterial nitrate reductase and electron transfer chains are involved in NO synthesis. We propose the existence of a nitrate-NO respiration process in nodules that could play a role in the maintenance of the energy status required for nitrogen fixation under oxygen-limiting conditions.

The effects of root hypoxia on ethylene biosynthesis and perception have been documented in many vegetative organs, but not extensively in fruit. Therefore, in the present study, the effects of root hypoxia on ethylene biosynthesis and perception were investigated in tomato (Solanum lycopersicum L.) fruit at five stages of the maturation phase. Our results showed that root hypoxia do not affect ethylene biosynthesis in fruit, but stimulates its reception from other plant part, as indicated by the increase in the expression of ethylene receptors ETR 1 and 3.

In order to investigate the effects of root hypoxia (1-2 % oxygen) on the nitrogen (N) metabolism of tomato plants (Solanum lycopersicum L. cv. Micro-Tom), a range of N compounds and N-assimilating enzymes were performed on roots and leaves of plants submitted to root hypoxia at the second leaf stage for three weeks. Obtained results showed that root hypoxia led to a significant decrease in dry weight (DW) production and nitrate content in roots and leaves. Conversely, shoot to root DW ratio and nitrite content were significantly increased. Contrary to that in leaves, glutamine synthetase activity was significantly enhanced in roots. The activities of nitrate and nitrite reductase were enhanced in roots as well as leaves. The higher increase in the NH(4)(+) content and in the protease activities in roots and leaves of hypoxically treated plants coincide with a greater decrease in soluble protein contents. Taken together, these results suggest that root hypoxia leaded to higher protein degradation. The hypoxia-induced increase in the aminating glutamate dehydrogenase activity may be considered as an alternative N assimilation pathway involved in detoxifying the NH(4)(+), accumulated under hypoxic conditions. With respect to hypoxic stress, the distinct sensitivity of the enzymes involved in N assimilation is discussed.

The arbuscular mycorrhizal (AM) symbiosis belongs to the strategies plants have developed to cope with adverse environmental conditions including contamination by heavy metals such as cadmium (Cd). In the present work, we report on the protective effect conferred by AM symbiosis to the model legume Medicago truncatula grown in presence of Cd, and on the 2-D-based proteomic approach further used to compare the proteomes of M. truncatula roots either colonised or not with the AM fungus Glomus intraradices in Cd-free and Cd-contaminated substrates. The results indicated that at the proteome level, 9 out of the 15 cadmium-induced changes in nonmycorrhizal roots were absent or inverse in those Cd-treated and colonized by G. intraradices, including the G. intraradices-dependent down-accumulation of Cd stress-responsive proteins. Out of the twenty-six mycorrhiza-related proteins that were identified, only six displayed changes in abundance upon Cd exposure, suggesting that part of the symbiotic program, which displays low sensitivity to Cd, may be recruited to counteract Cd toxicity through the mycorrhiza-dependent synthesis of proteins having functions putatively involved in alleviating oxidative damages, including a cyclophilin, a guanine nucleotide-binding protein, an ubiquitin carboxyl-terminal hydrolase, a thiazole biosynthetic enzyme, an annexin, a glutathione S-transferase (GST)-like protein, and a S-adenosylmethionine (SAM) synthase.

Here we examined the effects of root hypoxia (1-2% oxygen) on the physiology of the plant and on the biochemical composition of fruits in tomato (Solanum lycopersicum cv. Micro-Tom) plants submitted to gradual root hypoxia at first flower anthesis. Root hypoxia enhanced nitrate absorption with a concomitant release of nitrite and ammonium into the medium, a reduction of leaf photosynthetic activity and chlorophyll content, and an acceleration of fruit maturation, but did not affect final fruit size. Quantitative metabolic profiling of mature pericarp extracts by (1)H NMR showed that levels of major metabolites including sugars, organic acids and amino acids were not modified. However, ammonium concentration increased dramatically in fruit flesh, and ascorbate and lycopene concentrations decreased. Our data indicate that the unfavorable effects of root hypoxia on fruit quality cannot be explained by two of the well-known effects of root hypoxia on the plant, namely a decrease in photosynthesis or an excess in ethylene production, but may instead result from disturbances in the supply of either growth regulators or ammonium, by the roots.