Search

This study investigates the physiological and genetic diversity of Allorhizobium vitis strains in Morocco, focusing on their ability to produce and utilize opines as sources of carbon, nitrogen, and energy. Using ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF) and specific PCR assays, we identified and characterized opines in tumors induced in tomato plants by Moroccan strains of A. vitis. All strains showed the rare octopine/vitopine combination. Chromatographic analysis and molecular validation revealed metabolic and genetic uniformity in opine catabolism among the strains. These results suggest a homogeneity of octopine/vitopine tumour-inducing plasmids (pTi), which contribute to the uniformity of opine-related genes. This comprehensive approach provides insights into the molecular mechanisms of opine utilization and bacterial virulence, suggesting that targeting specific pathways or key virulence genes may be a strategy to control crown gall disease.

Soil salinity significantly impacts crop productivity. In response, plant growth-promoting rhizobacteria (PGPR) offer an innovative and eco-friendly solution to mitigate salinity stress. However, research on PGPR’s effects on crop physiology under varying salinity levels is still emerging. This study evaluates the impact of five bacterial strains, isolated from compost, on the growth of maize (Zea mays) and tomato (Solanum lycopersicum) plants under different levels of salt stress. This study involved treating maize and tomato seeds with five bacterial strains, and then planting them in a greenhouse under varying salt stress conditions (43 mM, 86 mM, 172 mM, 207 mM NaCl) using a Randomized Complete Block Design. Results showed that bacterial inoculation improved plant growth under saline conditions. S2015-1, S2026-2, and S2027-2 (Bacillus cereus, Acinetobacter calcoaceticus, Bacillus subtilis) were particularly effective in promoting plant growth under salt stress, especially at ionic concentrations of 43 mM and 86 mM, leading to a substantial increase in fresh and dry weight, with strain S2015-1 boosting chlorophyll by 29% at 86 mM in both crops. These results highlight the potential of PGPR to enhance crop resilience and productivity under salinity stress, promoting climate-smart agricultural practices.

Environmental concerns are gradually reducing the global yield capacity of agricultural systems, with climate change representing the most significant challenge. Globally, Potatoes are the most essential non-cereal crop. Therefore, understanding the potential impacts of climate change on potato production is crucial for maintaining future global food security. This study aims to explore the roles played by PGPMs in two distinct regions, which are characterized by different climatic conditions, to assess their influence on two potato varieties, namely Siena and Bellini. Inoculation with these strains, particularly the Aureobasidium pullulans strains Ach1-1 and Ach1-2, resulted in significant improvements in growth and yield. In 2018, impressive yields of 194.1 kg/0.05 ha and 186.6 kg/0.05 ha were recorded for the two strains, with the Ain Taoujdate site achieving yields of 157.1 kg/0.05 ha and 151.1 kg/0.05 ha for each of the two strains. Additionally, further observations revealed that the Siena variety is more susceptible to rot than the Bellini variety. However, Ach1-1 and Ach1-2 strains had a significant effect on this rot, showcasing their potential to mitigate this negative issue in the Bellini variety. These promising results underscore the potential of PGPMs to enhance potato production in the Fez–Meknes region of Morocco, contributing to global food security amid climate change.

Crown gall is a globally recognized bacterial disease caused by Agrobacterium tumefaciens. This bacterium is characterized by its potential to infect a wide range of plants, specifically fruit trees. In Morocco, almond trees (Prunus amygdalus) are among the most heavily affected species by this disease. In our study, all tested bacteria were isolated in the laboratory from infected almond samples exhibiting tumors at the crown and root of the sampled trees collected from northwestern of Morocco. Biochemical, pathogenicity and molecular identification were performed to identify the causal agent of almond crown gall. Molecular identification was done using a duplex PCR (A/C9 and A/E9) targeting virD2gene located in the pTi plasmid, which is the oncogenic element of the bacterium. The results showed that 12 from 20 isolates were identified as tumorigenic A. tumefaciens with the presence of pTi. Moreover, these isolates were found to exhibit tumorigenic properties both in vitro and in vivo when tested on indicator plants, specifically tomato and carrot discs. The efficacy of agrocin synthesized by Agrobacterium radiobacter strain K1026, a biopesticide known as NoGall, was tested in vitro and in planta against tumorigenic strains of A. tumefaciens. Our results revealed a significant inhibitory effect in vitro, with inhibition percentages ranging from 29.5% to 38.9%. Additionally, we observed a complete reduction in tumor growth at the inoculation sites on indicator plants, with a 100% reduction percentage.

The Sebou River Basin is vital for Moroccan agriculture, particularly in terms of producing industrial crops, fruits, vegetables, and olive oil. It is especially significant in viticulture, accounting for 80% and 60% of the national production area for wine and table grapes, respectively. However, the prevalence of diseases and pests requires extensive pesticide application in vineyards. This study aims to assess the impact of pesticides used in vineyards on the environment, human health and their associated sustainability. Agro-environmental indicators were evaluated across 30 vineyards covering 1197 hectares. Results show an average treatment frequency of 24.05 applications per growing cycle, the highest among grape-producing countries, with 77.94% being fungicides. The Quantity of Active Substances Indicator (QASI) reveals a high pesticide application rate of 44.60 Kg a.i./ha. Over 50% of chemicals are classified as “hazardous” based on the Environmental Impact Quotient (EIQ). A Pesticide Environmental Risk Indicator model (PERI) identifies three active ingredients with a high Environmental Risk Score (>5). Life Cycle Assessment (LCA) reveals that copper sulfate has significant environmental impacts compared to Mancozeb and sulfur. These findings highlight the extensive use of pesticides in vineyards, posing challenges to long-term sustainable agriculture due to associated environmental and health risks.

L'isolement en culture pure de la souche Xylella fastidiosa liée au syndrome de déclin rapide de l'olivier (OQDS), récemment observé dans les Pouilles (sud de l'Italie) a été tenté à partir des plantes symptomatiques naturellement infectée, principalement Olea europaea L., Polygala myrtifolia et Rosmarinus officinalis, en utilisant les méthodes d'impression et d'extraction de la sève. Avant l'isolement, RT-LAMP et qPCR ont été utilisés pour déterminer la présence de X. fastidiosa chez tous les hôtes. Des cultures bactériennes pures ont été obtenues à partir d'extraits d'Olea europaea L. et de Polygala myrtifolia étalés dans un milieu tamponné d'extrait de cystéine-levure (BCYE). Deux isolats d'olive ont ensuite été typés à l'aide du système de séquençage multilocus (MLST). Les résultats indiquent qu'Olea europaea a un grand potentiel d'isolement, et la méthode d'impression a présenté des résultats nettement meilleurs. MLST montre des points communs génétiques avec la souche De Donno (ST53) et confirme que nous avons toujours le même type de séquence ST53 dans la région.

Bromus are annual herbaceous plants belonging to the Poaceae family. It’s about the weeds that infest cereals. The most harmful one is Bromus rigidus Roth. The purpose of this study is to find out the effect of different treatments on the germination and viability of ripgut brome. The first test in vitro germination was carried out on a collection, from 1993 to 2015, under controlled conditions in temperature (25°C), photoperiods (eight hours of darkness and sixteen hours of light) and relative humidity (70%). Several treatments were used: gibberellic acid (1g/l), hot water (ranging from 60°C to 90°C), sodium azide (1g/0,75l), potassium nitrate (10g/l) and sulfuric acid 5%. The results obtained showed that the bromus seeds collected on 2013 germinated at a rate of 60% without any treatment and of 100% with the different treatments. Gibberellic acid is the most element promoting germination. The germination rate of bromus rigidus depends closely on the year of seed harvest and also on the treatment carried out. The viability test in vitro under the effect of tetrazolium chloride (C19H15ClN4) which is used only on non-germinated seeds, showed that the seeds remain viable for seven years and they germinate only if favorable conditions are met.

Codling moth, Cydia pomonella L., is a major pest of pome fruits and walnuts worldwide. Screening the susceptibility of apple varieties to C. pomonella infestation is an important step to develop a sustainable management program against this pest. Therefore, the present study aimed to explore potential correlations between pest damage and several physical (firmness, weight, and diameter), chemical (pH, SSC, and TA), and biochemical (polyphenols) fruit properties collected from two sites with distinctively twelve and seven commercial apple varieties. The study was conducted in two distinct Moroccan regions to highlight whether the traits influencing the insect’s preference could be similar for different varieties under contrasted climates. In both regions, results revealed that the pest damage varied significantly across apple varieties as well as between observation dates. The late and medium maturing varieties had similar damage patterns and were heavily attacked compared to early maturing ones. The preferred varieties were Galaxy Gala, Obro Gala, Golden Smoothee, Black Staymen, and Idared, while the least preferred ones were Anna, Dorsett, and Stark Delicious. Some physical and chemical fruit properties seemed to be associated with the insect behavior, in particular, firmness and pH were positively correlated to pest damage. Moreover, the research suggested that infestations might be influenced by diameter, weight, and polyphenol content of fruits.

Olive leaf spot (OLS), also called olive scab and peacock eye, caused by Fusicladium oleagineum, is a major disease that causes significant damage to olive trees. However, we still lack information about how cultivar and environmental factors influence disease development. In this study, evaluation of the incidence and severity on twenty olive cultivars (Olea europaea L.), maintained in an ex situ collection in Morocco, was carried out monthly during the period from March to July 2021. Biochemical parameters were also evaluated for each cultivar including leaf chlorophyll, polyphenols and flavonoid contents. Results revealed that the OLS incidence was highly correlated with severity (r = 0.94) and found to be related to climatic conditions and cultivars. The studied cultivars were classified into four major groups, i.e., susceptible, moderately susceptible, moderately resistant and resistant. Finally, our investigations revealed a partial relationship between resistance to the OLS disease and phenolic and flavonoid leaf contents, supporting the assumption of the potential involvement of such components in cultivar resistance to the disease. Overall, our work highlights the importance of characterizing olive cultivar resistance to OLS in driving the choice of the best varieties for an effective control of the disease in specific warming regions such as Morocco.

In order to discover new natural resources with biological properties, the chemical composition, the antioxidant and antimicrobial activities, and the potential use as food preservative of essential oils of Moroccan Achillea odorata subsp. pectinata (AOpEO) and Ruta montana (RMEO) were studied. Gas chromatography-mass spectrometry (GC-MS) analysis revealed the presence of 21 and 25 compounds in AOpEO and RMEO, respectively. The results showed that the major compounds of AOpEO are camphor (45.01%), bornyl acetate (15.07%), borneol (11.33%), β-eudesmol (4.74%), camphene (3.58%), and 1.8-cineole (eucalyptol) (2.96%), whereas 2-undecanone (63.97%), camphor (3.82%) and cyclopropanecarboxylic acid (3.66%) were the main components of RMEO. The antioxidant activities were evaluated by diphenylpicrylhydraziyl radical (DPPH) and reducing power assays. The antimicrobial activities of essential oils were tested against bacterial strains and food contaminant yeast using agar disc diffusion and microdilution methods. A significant antimicrobial activity of AOpEO was observed against Bacillus subtilis, Proteus mirabilis and Candida albicans, compared to RMEO. The efficacy of AOpEO was also evaluated in model food systems (cabbage and barley) artificially inoculated during storage. The results found that the adding of a minimal inhibitory concentration (MIC) and 4× MIC were potent in decreasing the Proteus mirabilis growth in food model systems. Our findings suggested that AOpEO may be potentially used as an alternative food preservative.

Aims: This study aimed to i) identify Pseudomonas savastanoi pv. savastanoi (Pss) as a causal agent of the olive knot on the basis of biochemical, pathogenicity and PCR technique ii) investigate in vitro bacterial resistance toward copperbased compounds and efficiency of some antibiotics on pathogen suppression. Methodology and results: Biochemical, pathogenicity and molecular identification based on alkaline method for the DNA extraction were performed to identify possible causal agent of the olive knot. Copper resistance for Pss strains was evaluated by inoculation of bacterial suspensions into YPG medium, containing the cupric sulfate at 0, 100, 250 and 500 ppm. The efficiency of eight antibiotics on Pss strain was evaluated at different concentrations. Fifty-nine isolates caused typical knots at the site of inoculation with bacterial suspensions. All isolates have been identified as Pss using specific primers. No resistance to copper was detected with concentration of 500 ppm. In contrast, copper resistance was found during 48 h with lower concentration (100 or 250 ppm). The maximal inhibition of Pss 2102-4M was observed with the highest concentration (20 μg/mL) of the Aureomycin, Streptomycin and Novobiocin with inhibition diameters of 30, 24 and 10 mm, respectively. Whereas, Colchicine, Bacitracin, Cephalex, Ampicillin and Cycloserine have no inhibitory effect on the Pss 2102-4M strain. Conclusion, significance and impact of study: The alkaline method for the DNA extraction from pure culture was reliable and rapid and can be recommended for molecular detection the causal agent of the olive knot. This is the first report determined copper resistance levels of Moroccan strains of Pss and in vitro evaluated for the susceptibility towards the antibiotics. [ABSTRACT FROM AUTHOR]

This study aims to investigate the yield, chemical composition and inhibitory effect of four essential oils of eucalyptus collected from Morocco on the pathogenic Allorhizobium vitis S4 causal agent of the crown gall of grapevine. The identification of the constituents of essential oils was performed by GC-MS analysis and the antibacterial activity was evaluated using an aromatogram test. The yield of different samples of eucalyptus ranged from 2-4.5%. The results of chemical compounds analysis show that the major compounds of eucalyptus essential oils are, 1,8-Cineol (Eucalyptol) (65.55-78.11%), α-Pinene (3-15.21%), 2-β-Pinene (2.33-5.27%) and p-Cymene (0.79-11.51%). All eucalyptus essential oil exhibits an antibacterial activity in vitro against Allorhizobium vitis strain S4 with a percentage of inhibition and minimal inhibitory concentration values in the range of 13.67-20.50 % and 20-40 mg/mL, respectively.