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The goal of this study was to determine for the first time the polyphenol content, antioxidant, and gastroprotective properties of the roots and leaves of Reichardia picroides. TPC considerably varied as a function of organs and solvent nature and ranged from 50 to 284.80 mg GAE/g DW. Leaves exhibited the highest amount of phenolics by using acetone 70%, the same tendency was observed for antioxidant activity. Besides, in vivo gastro-protective effects following HCl/EtOH-induced ulcer models displayed that roots extract at a high dose (500 mg) seemed to be the best performing extract with a decrease of ulceration index (UI) and an increase in the percentage of protection (PP), SOD, CAT, and GPX activities. All these data have been proved with principal component analysis (PCA). Overall, the results indicated that R. picroides could be considered a valuable source of natural compounds, which are beneficial for human health. [ABSTRACT FROM AUTHOR]

Argan tree growth and production are both affected by drought stress, which is recognized as a critical and serious environmental issue worldwide. This study aims to examine the effect of a multi-species consortium of arbuscular mycorrhizal fungi (AMF) "Rhizargan consortium", on the leaf water status and photosynthesis in drought-stressed argan seedlings. The performances of Rhizargan consortium were compared to those of a single pure commercialized strain of Rhizophagus irregularis. Seedlings of two argan tree ecotypes were subjected to three water regimes: 30, 60, and 100% field capacity (FC). After twelve months of drought stress, mycorrhizal argan seedlings showed a significant increase in leaf water potential, stomatal conductance, and maximum efficiency of PSII (Fm/Fv) than those without mycorrhiza inoculation. Moreover, AMF inoculation led to significant leaf accumulation of chlorophyll and carotenoid upon drought imposition. Nonetheless, severe drought stress (30% FC) decreased these physiological/photochemical attributes as well as both frequency and intensity of mycorrhization, but to a lesser extent in the argan seedlings inoculated with "Rhizargan consortium". This study contributes to advances in the knowledge of the indigenous Rhizargan consortium's ability to induce drought tolerance in argan trees. [ABSTRACT FROM AUTHOR]

Morocco decides to launch a program to create additional argan orchards to meet the high national and worldwide demand for argan products, which is a specie so unique in the world threatened by the global climate change effect. The current study aims to evaluate the efficiency of a multi-species consortium of autochthonous mycorrhizal fungi 'Rhizargan' isolated from 15 Moroccan argan soils in promoting mineral nutrition intake, phosphatase activities, and plant growth of argan trees. The research was conducted on two contrasting ecotypes of argan (Admine and Lakhsas). For 25 months, the performance of argan seedlings inoculated with Rhizargan consortium was monitored and compared to those inoculated with a pure commercialized strain of Rhizophagus irregularis. The results showed that inoculation with the 'Rhizargan consortium' improved plant growth, mineral nutrition, and phosphatases activity more than R. irregularis inoculation. Inoculated Lakhsas and Admine seedlings with Rhizargan consortium increased shoot height by 19% and 26%, and alkaline phosphatase activity by 27% and 14%, as compared to R. irregularis. Our findings can significantly benefit the arganiculture program, as an ecofriendly strategy, by using Rhizargan consortium as biofertilizers adapted to a wider range of argan forest' pedoclimatic conditions. [ABSTRACT FROM AUTHOR]

Morocco has launched a vast program to rehabilitate the argan tree (Argania spinosa) and extend its cultivation under modern management (arganiculture). The promotion of tree growth in the greenhouse and the field as well as their tolerance to biotic and abiotic constraints are key factors for the success of this program. Arbuscular mycorrhizal fungi play an important role in improving mineral nutrition, growth, development, and tolerance of plants to biotic and abiotic stresses. The objective of the present work is to evaluate the effectiveness of promoting growth and mineral nutrition of argan trees by a multi-species consortium of autochthonous mycorrhizal fungi 'Rhizargan' isolated from 15 Moroccan argan soils. The study was conducted on two contrasting ecotypes of argan (Admine) and (Lakhsas). The performance of plants inoculated with 'Rhizargan consortium' was monitored for thirteen months and then compared to that of plants inoculated with a pure commercialized strain of Rhizophagus irregularis. Results show that inoculation with 'Rhizargan consortium' improves plant growth and mineral nutrition more than R. irregularis. Our results can strongly benefit the arganiculture program, especially since 'Rhizargan consortium' is composed of several endomycorrhizal species allowing them to respond to a greater diversity of crops and pedoclimatical conditions. [ABSTRACT FROM AUTHOR]

Ulvan, carrageenan, alginate and laminarin were tested in olive trees' twigs to elicit phenolic metabolism and control verticillium wilt of olive (VWO) caused by Verticillium dahliae. The elicitation effect was determined through phenylalanine ammonia-lyase activity, total polyphenol content and lignin content. VWO was assessed in twigs previously elicited (24 h) and maintained in a solution containing bio-elicitors (2 g/L) and conidial suspension (106 conidia/mL). Our results showed stimulation of the phenolic metabolism and the decline of wilt symptoms. Ulvan reduced significantly the area under the disease progress curve for severity to 39.9% and the final incidence to 28.9%. Ulvan and alginate produced significant inhibitory rates on mycelial growth of the fungus in vitro. Seaweed polysaccharides might help to overcome VWO by strengthening the host defense metabolism and restricting the pathogen's growth. [ABSTRACT FROM AUTHOR]

Our study was undertaken to ascertain whether the change of the water status and the activation of superoxide dismutase and their isoenzymes in Argan tree can support edaphic drought tolerance and its recovery under rehydration. An experiment was conducted on four contrasting ecotypes of Argania spinosa plants: two contrasting coastal ecotypes (Admine (Adm) and Rabia (Rab)) and two contrasting inland ecotypes (Aoulouz (Alz) and Lakhssas (Lks)). Drought stress significantly decreased the leaf water potential and stomatal conductance in the four contrasted ecotypes. In terms of biochemical responses, significant accumulation of carbonyl groups, hydrogen peroxide and superoxide radical has been recorded in the leaves of stressed plants reflecting oxidative stress. In parallel, the activities of total superoxide dismutase (SOD) and their isoenzymes Cu/Zn-SOD, Cu/Zn-SOD and Fe- SOD were also found to have increased to scavenging ROS and protecting the cell against induced oxidative stress. The recovery kinetics of A. spinosa, as a response to rehydration, were significant and rapid. According to the traits having the most discriminating power, both inland ecotypes (Lks and Alz) showed a better upregulation of its protective mechanisms compared to coastal ecotypes (Rab and Adm). All these adaptive traits make the inland ecotypes as an elite resource of drought tolerance and might become the new focus of domestication research of argan tree in arid and semi-arid environments. [ABSTRACT FROM AUTHOR]

In order to study the role of phenolic metabolism in the defense of the olive-tree against Spilocaea oleagina, three defense components: soluble phenols, parietal phenols, lignin and phenylalanine ammonia-lyase (PAL), were studied in two different varieties: a resistant (Picholine du Languedoc) and a susceptible (Moroccan Picholine). The inoculation of olive-tree leaves by Spilocaea oleagina induces a foliar necrosis whose speed of onset and expansion distinguishes clearly the two studied varieties according to their behaviour to the leaf-spot disease. For the resistant variety, these symptoms are composed of small necrotic lesions, whereas for the susceptible variety, they appear as extended necrotic spots. These symptoms are accompanied by an increase in the accumulation of the contents of soluble and parietal phenols, the intensification of the lignification and the induction of the PAL activity of which the speed and intensity plainly distinguish both varieties under study. These results reveal that the response of phenolic metabolism to the resistance of the olive tree to the leaf-spot disease appears to occur in the early stages of infection leading to an increase in the biosynthesis of the contents of three defense components (soluble phenols, parietal phenols and lignin). [ABSTRACT FROM AUTHOR]