Browsing by Author "Meklat, Atika"
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Item Open Access Actinobacteria: an underestimated source of potential microbial biocontrol agents against fusarium-related diseases in cultivated crops(Springer, 2023-07-28) Djemouai, Nadjette; Meklat, Atika; Yekkour, Amine; Verheecke-Vaessen, CarolCrop infections with Fusarium spp. and associated mycotoxins have devastating economic implications and are a significant limitation to fifteen of the seventeen United Nations Sustainable Development Goals. Therefore, it is necessary to develop innovative strategies to reduce or eliminate diseases caused by Fusarium spp. in cultivated crops. Management of Fusarium-related diseases using beneficial microorganisms is a promising and eco-friendly solution. In this context, actinobacteria are considered one of the best candidates because of their multifunctional properties, which consist in the reduction of Fusarium spp. diseases and the promotion of plant growth. Actinobacteria represent a large Gram-positive bacterial phylum that is widespread in different environments, especially in soil. They are principally known for their versatile capacity to produce biologically active molecules with potential applications in different fields, including agriculture. As Fusarium species threaten diverse crops worldwide and cause global yield and quality losses that can negatively impact food security, the use of actinobacteria for plant diseases management is gaining interest as a safer and more potent alternative to ineffective synthetic-based pesticides. Thus, this work aims to review and highlight the importance of actinobacteria as microbial biocontrol agents and discuss the current research on Fusarium spp. diseases with a focus on species that threaten economically important crops, such as F. graminearum, F. oxysporum, F. solani, and F. culmorum. This review also presents actinobacteria-based products that have been patented for Fusarium disease control. We aim to provide valuable data, guidance and advancements for future research on microbial biocontrol against Fusarium-related diseases. In addition, this review emphasizes the need for further research about the impact of actinobacteria-Fusarium interactions on mycotoxin production. It also highlights the need of in-depth understanding microbial biocontrol mechanisms to ensure safe and sustainable crop production worldwide.Item Open Access Biological activities of Streptomyces sp. Bts40 isolated from the rhizosphere of Artemisia herba-alba Asso(Universitatea din Oradea, 2022-01-04) Djemouai, Nadjette; Meklat, Atika; Gaceb-Terrak, Rabéa; Oulad Hadj Youcef, Khadidja; Nacer, Asma; Mokrane, Salim; Bouras, Noureddine; Verheecke-Vaessen, CarolActinobacteria isolated from the rhizosphere of plants are of interest as they produce a diverse range of molecules, such as antibiotics and enzymes. This study investigates the antibacterial activity, plant growth-promoting (PGP) abilities as well as the production of extracellular enzymes by the actinobacterial strain BTS40. This strain was isolated from the rhizospheric soil of the medicinal plant Artemisia herba-alba Asso that was naturally grown in a semi-arid environment. Morphological characteristics showed that the strain BTS40 belongs to the genus Streptomyces. Analysis of BTS40’s 16S rRNA gene sequence showed 99.45% similarity to Streptomyces alboniger NRRL B-1832T, in the EzTaxon database. This actinobacterium showed only antibacterial activity against Gram-positive bacteria. The strain also showed potential multiple traits for plant growth promotion and hydrolysis of enzymes. Hence, this study reveals that strain BTS40 has multiple PGP traits and produces many extracellular hydrolytic enzymes.Item Open Access Polyphasic characterization of Aspergillus section Flavi isolated from animal feeds in Algeria(Wiley, 2019-12-13) Bouti, Karima; Verheecke-Vaessen, Carol; Mokrane, Salim; Meklat, Atika; Djemouai, Nadjette; Sabaou, Nasserdine; Mathieu, Florence; Riba, AmarIn Algeria, little information is available on the population structure of Aspergillus section Flavi in raw materials and resultant animal feeds. A total of 172 isolates belonging to Aspergillus section Flavi were recovered from 57 animal feeds and identified on the basis of macro and micro‐morphological characters, mycotoxin production and genetic relatedness. For the molecular analysis, sequencing of the calmodulin gene (CaM) and the internal transcribed spacer (ITS) regions were performed for representative isolates. Four distinct morphotypes were distinguished: Aspergillus flavus (78.5%), Aspergillus tamarii (19.2%), Aspergillus parasiticus (1.7%), and Aspergillus alliaceus (0.6%). All A. flavus isolates were of the L type and no correlation between sclerotia production and aflatoxigenicity was observed. Our results showed that 68% of the A. flavus strains produced aflatoxins B (AFB), and 72.7% were cyclopiazonic acid (CPA) producers. The three isolates of A. parasiticus were able to produce AFB and aflatoxins G but not CPA whereas, all the strains of A. tamarii produced only CPA. The obtained results revealed the presence of different species of Aspergillus section Flavi, among which were aflatoxin producers. This study provides evidence useful for considerations in aflatoxin control strategies.