Publications Internationales
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Item Exploring the antifungal properties of tannin extracts from Olea europaea var. rougette leaves against Aspergillus spp.(Springer, 2024) Bennacer, Amel; Sahir-Halouane, Fatma; Aitslimane-Aitkaki, Sabrina; Tihar-Benzina, Farida; Oukali, Zahia; Oliveira, Ivo Vaz; Rahmouni, Naima; Aissaoui, Mohammed; Mohankumar, RamarDue to significant health risks associated with chemical antifungal agents in food storage, safe and natural sources are now one of the most frequently demanded ingredient for food preservation. Byproducts from olive trees provide an affordable and sustainable source of bioactive chemicals. This study will examine the mycelial growth and germination-inhibitory properties of Olea europaea var. rougette leaves and characterize their phytochemical makeup.The phytochemical screening revealed the presence of polyphenolics compounds mainly tanins.The chemical composition was analyzed by gas chromatography mass spectrometry (GCMS). Total polyphenolic content (TPC), hydrolysable tannins content (HTC) and condensed tannin content (CTC) were assessed using Foilin ciocalteu, potassium iodide and vanilline methods, respectively. The mycelial growth and germination inhibition properties were examined on soft wheat based solid and liquid media. Tannic extract (ethyl acetate extract) revealed highest amounts in polyphenols, hydrolysable tanins and condensed. GC–MS profile of tannic extract showed the presence of 26 bioactive molecules known for their antifungal potential, mainly: Guaiacol (0.12%), 2-methoxy-4-vinylphenol (1.52%), Syringol (0.18%), p-tyrosol (4.70%), homovanillyl alcohol (1.32%), 4-propylresorcinol (1.07%), β-camphor (0.17%), β-turmerone (1.57%) and 4-phenyl-quinolin-2-ol (6.58%). The tannic extract (ethyl acetate fraction) showed significant mycelial growth and germination inhibition activities in contrast to hydro-acetonic and dichloromethanic extracts. Furthermore, myelial growth inhibition showed more effectiveness in comparison to germination inhibition technique.The results suggested that byproducts of Olea europaea var. rougette leaves are a substantial natural source of bioactive compounds, especially tannins with potent antifungal characteristics in vitro which make it interesting to investigate its effectiveness in vivo.Item Trichoderma spp. isolates from the rhizosphere of healthy olive trees in northern Algeria and their biocontrol potentials against the olive wilt pathogen, Verticillium dahliae(Springer, 2021) Reghmit, Abdenaceur; Benzina‑tihar, Farida; López Escudero, Francisco Javier; Halouane‑Sahir, Fatma; Oukali, Zahia; Bensmail, Souhila; Ghozali, NourelhoudaTrichoderma species are known for their ability to control many plant diseases. In this study, fifteen (T1–T15) indigenous strains of Trichoderma spp. isolated from rhizosphere soils of olive in northern Algeria were investigated for their biocontrol potential against eleven strains of Verticillium dahliae, the causal agent of wilting on olive (Olea europea cv. europea L.). Direct and indirect confrontation assays were performed to investigate if isolates of Trichoderma affect mycelium growth. In addition, gas chromatography–mass spectroscopy (GC–MS) was applied to identify the volatile organic compounds (VOCS) produced by the T2 isolate. Besides, Trichoderma isolates were screened for the production of extracellular enzymes on solid medium including chitinases, proteasesand cellulases. Results showed that Trichoderma isolates demonstrated an effective potential in reducing mycelium growth against V. dahliae in vitro. T12 was the highest antagonistic of the Trichoderma isolates by direct confrontation assay method. This isolate exhibited an average inhibition rate of 68.86% against V. dahliae isolates, whereas the evaluation of volatile metabolites effect revealed that inhibition percentage of radial growth varies between 55.26 and 65.93%. Importantly, results showed the presence of 33 compounds detected in the methanolic and hexanic fraction of T2 isolate, including important volatile compounds with antifungal activities such as Undecane, Octadecane, Eicosane, 13-Docosenamide, (Z), Hexadecanamide, 9-Octadecenamide, (Z), Cyclopentanone, 2-methyl, Tetradecanoic acid, propyl ester, Tetradecanoic acid, oleic acid, and n-Hexadecanoic acid. Interestingly, all isolates tested showed chitinolytic, proteolytic and cellulolytic activity. T2 and T12 were the effective Trichoderma isolates showing high chitinase production on solid medium. Besides that, isolates T2 and T6 demonstrated the highest chitinolytic and proteolytic activity with values 0.043 µmol/ml/min and 0.019 µmol/ml/min, respectively. Overall, the isolates, T2, T6, and T12 are the most effective agents against olive wilt pathogen V. dahliae in vitro. Hence, they could be further investigated for biocontrol of olive wilt in vivoItem Effective biofertilizer trichoderma spp. isolates with enzymatic activity and metabolites enhancing plant growth(Research square, 2022) Reghmit, Abdenacer; Benzina-tihar, Farida; Djeziri, Mourad; Hadjouti, Rima; Oukali, Zahia; Sahir-Halouane, FatmaTrichoderma species have been widely recognized as biofertilizer fungi for their ability to produce phytohormones and enhancing plant growth. In our current study, fifteen strains of Trichoderma spp (T1- T15) were screened for their capacity to produce phytohormones and metabolites eliciting plant growth. The stains were previously isolated from olive rhizosphere soil in northern Algeria. Plant growth promoting (PGP) potential of Trichoderma spp. was evaluated in-vitro through the production of phosphatases, iron chelators (siderophores), cyanhydric acid (HCN) and ammonia (NH3). Besides, Plant growth phytohormones such as gibberellic acid and indole-3-acetic acid (IAA) were assessed quantitatively by a colorimetric assay. Results showed an effective potential of Trichoderma isolates in PGP biomolecules production. Importantly, qualitative estimation of phosphate solubilization indicates that T10 gave the highest P-solubilization on medium Pikovskaya’s with a solubilization index (SI) of 3, whereas, the high capacity nitrogen-fixing was related to T8. In other hand, quantitative analysis of IAA and gibberellic acid revealed a production varying between (1.30 µg mL − 1 − 21.15 µg mL − 1 ) and (0.53µg/ml − 7.87µg/ml), respectively, the highest amount of both phytohormones was obtained by T11 isolate. Indeed, analysis of ethyl acetate extracts of T11 isolate by high-performance liquid chromatography (HPLC) revealed a high amount (71.19 mgL − 1 ) of IAA. Overall, Results showed clearly that isolate T11 has promising plant growth promoting properties. Hence, this native Trichoderma isolate (T11) identified as Trichoderma harzianum strain (OL587563) could be used later as biofertilizer for sustainable olive crop agricultureItem Extraction of essential oil from inula viscosa (L.) leaves : composition, antifungal activity and kinetic data(Taylor & Francis, 2016) Haoui, Imad Eddine; Derriche, Ratiba; Madani, Leila; Oukali, ZahiaItem Analysis of the chemical composition of essential oil from algerian inula viscosa (L.) Aiton(Elsevier, 2015) Haoui, Imad Eddine; Derriche, Ratiba; Madani, Leila; Oukali, Zahia