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This study aimed to characterize the halotolerant capability, in vitro, of selected actinomycetes strains and to evaluate their competence in promoting halo stress tolerance in durum wheat in a greenhouse experiment. Fourteen isolates were tested for phosphate solubilization, indole acetic acid, hydrocyanic acid, and ammonia production under different salt concentrations (i.e., 0, 0.25, 0.5, 0.75, 1, 1.25, and 1.5 M NaCl). The presence of 1-aminocyclopropane-1-carboxylate deaminase activity was also investigated. Salinity tolerance was evaluated in durum wheat through plant growth and development parameters: shoot and root length, dry and ash-free dry weight, and the total chlorophyll content, as well as proline accumulation. In vitro assays have shown that the strains can solubilize inorganic phosphate and produce indole acetic acid, hydrocyanic acid, and ammonia under different salt concentrations. Most of the strains (86%) had 1-aminocyclopropane-1-carboxylate deaminase activity, with significant amounts of α-ketobutyric acid. In the greenhouse experiment, inoculation with actinomycetes strains improved the morpho-biochemical parameters of durum wheat plants, which also recorded significantly higher content of chlorophylls and proline than those uninoculated, both under normal and stressed conditions. Our results suggest that inoculation of halotolerant actinomycetes can mitigate the negative effects of salt stress and allow normal growth and development of durum wheat plants.
Rihab Djebaili; Marika Pellegrini; Massimiliano Rossi; Cinzia Forni; Maria Smati; Maddalena Del Gallo; Mahmoud Kitouni. Characterization of Plant Growth-Promoting Traits and Inoculation Effects on Triticum durum of Actinomycetes Isolates under Salt Stress Conditions. Soil Systems 2021, 5, 26 .
AMA StyleRihab Djebaili, Marika Pellegrini, Massimiliano Rossi, Cinzia Forni, Maria Smati, Maddalena Del Gallo, Mahmoud Kitouni. Characterization of Plant Growth-Promoting Traits and Inoculation Effects on Triticum durum of Actinomycetes Isolates under Salt Stress Conditions. Soil Systems. 2021; 5 (2):26.
Chicago/Turabian StyleRihab Djebaili; Marika Pellegrini; Massimiliano Rossi; Cinzia Forni; Maria Smati; Maddalena Del Gallo; Mahmoud Kitouni. 2021. "Characterization of Plant Growth-Promoting Traits and Inoculation Effects on Triticum durum of Actinomycetes Isolates under Salt Stress Conditions." Soil Systems 5, no. 2: 26.
Excessive use of chemical products in agriculture is causing significant environmental pollution and the loss of lands and fertility of agricultural soils. Plant-growth-promoting bacteria are a valid alternative strategy for sustainable agriculture. The aim of this study was to select actinomycete strains based on their plant-growth-promoting traits and to investigate their root association abilities and biostimulant effects on Solanum lycopersicum. The strains were investigated for their phosphate solubilization ability, production of indole-3-acetic acid, hydrocyanic acid, and ammonia, and several enzymatic activities. Bacteria–plant-root associations were studied by scanning electron microscopy. A greenhouse experiment was carried out to assess inoculation effects. Of sixty isolates, fourteen strains showed significant plant-growth-promoting traits. All fourteen strains solubilized phosphate, produced ammonia, and showed several enzymatic activities at different rates. The production of indole-3-acetic acid was shown by nine strains, while hydrocyanic acid production was observed in eleven of them. Scanning electron microscopy revealed that strains have good in vitro plant root association and colonization abilities. In planta inoculation by actinomycete strains positively influenced plant growth parameters. The best results were shown by seven actinomycete strains, suggesting their possible utilization as biofertilizer agents for sustainable agriculture.
Rihab Djebaili; Marika Pellegrini; Maria Smati; Maddalena Del Gallo; Mahmoud Kitouni. Actinomycete Strains Isolated from Saline Soils: Plant-Growth-Promoting Traits and Inoculation Effects on Solanum lycopersicum. Sustainability 2020, 12, 4617 .
AMA StyleRihab Djebaili, Marika Pellegrini, Maria Smati, Maddalena Del Gallo, Mahmoud Kitouni. Actinomycete Strains Isolated from Saline Soils: Plant-Growth-Promoting Traits and Inoculation Effects on Solanum lycopersicum. Sustainability. 2020; 12 (11):4617.
Chicago/Turabian StyleRihab Djebaili; Marika Pellegrini; Maria Smati; Maddalena Del Gallo; Mahmoud Kitouni. 2020. "Actinomycete Strains Isolated from Saline Soils: Plant-Growth-Promoting Traits and Inoculation Effects on Solanum lycopersicum." Sustainability 12, no. 11: 4617.
The main purpose of this research is to study the microbial diversity of actinobacteria, living in “Ezzemoul” and “Djendli” sebkhas soils. These salt lakes are situated in the east of Algeria and they are microbiologically underexploited. Such unexplored ecological niches have been considered by many authors as sources of novel actinobacteria and bioactive molecules. Actinobacteria play an important role in safeguarding the environment by improving plant growth through nitrogen fixation, biodegradation, and bioremediation. Therefore, studying the diversity and distribution of actinobacteria in such special environments is important for determining the ecological and biotechnological roles of these microorganisms. In this article, we focused on the occurrence and the diversity of actinobacteria from sebkhas using two techniques: cultural and culture-independent (molecular cloning). The latter are based on phylogenetic analysis of the 16S rDNA gene. Thus, the cultural method allowed us to obtain 62 isolates: 40 from the “Ezzemoul” site and 22 from the “Djendli” site. These isolates tolerate mainly 2, 5, and 10% sodium chloride (NaCl) and belong to the genera Nocardiopsis, Streptomyces, and Rhodococcus. Moreover, the molecular cloning gave us 39 clones. Twenty-four clone sequences from “Ezzemoul” site are affiliated to the genera Demequina, Plantactinospora, Friedmanniella, and Mycobacterium. Also, 15 clone sequences from “Djendli” site are related to the genera Marmoricola, Phytoactinopolyspora, Streptomyces, and to an unclassified actinobacterial clone. Some sequences from both sites are related to uncultured clones. In addition to the data provided by the cultural method, molecular cloning allowed us to have additional information about the unknown actinobacteria, uncultured ones as well as on the genera that exist in both sites. So, the cultural method is complementary to the culture-independent one, and their combination revealed an important diversity in targeted saline environments. Furthermore, all new isolated strains that tolerate 10% NaCl may have a very interesting biotechnological potential in the future.
Maria Smati; Mahmoud Kitouni. Diversity of actinobacteria in the marshes of Ezzemoul and Djendli in northeastern Algeria. European Journal of Ecology 2019, 5, 41 -53.
AMA StyleMaria Smati, Mahmoud Kitouni. Diversity of actinobacteria in the marshes of Ezzemoul and Djendli in northeastern Algeria. European Journal of Ecology. 2019; 5 (2):41-53.
Chicago/Turabian StyleMaria Smati; Mahmoud Kitouni. 2019. "Diversity of actinobacteria in the marshes of Ezzemoul and Djendli in northeastern Algeria." European Journal of Ecology 5, no. 2: 41-53.