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Hemissi I.,French National Institute for Agricultural Research | Hemissi I.,Institute National Dagronomie Of Tunis | Hemissi I.,Center National des science et Technology Nucleaires | Mabrouk Y.,Center National des science et Technology Nucleaires | And 6 more authors.
African Journal of Microbiology Research | Year: 2011

Rhizoctonia solani is one of the most important soil-borne fungal pathogens that attack the roots of plant and causes significant damage to different plants particularly to chickpeas (Cicer arietinum L.). The aim of this work is to study the antagonistic activity of different Rhizobium strains against R. solani in dual culture in vitro and under greenhouse conditions. The benefits of rhizobial inoculant in nitrogen fixation, phosphorous uptake and on plant growth promoting were demonstrated with 42 Rhizobium strains. Among the 42 strains tested, 24 isolates had effective control on R. solani in vitro. In order to study the biological control mechanisms, the Rhizobium strains ability to produce volatile compounds and to solubilise phosphate were investigated. The results showed that 10 strains were able to solubilise phosphorus and 13 strains produced volatile compounds. In pot trials, the percentage of chickpea plants inoculated with different rhizobia showed significant reduce of root rot symptoms compared to the control growing in uninoculated soil. Among these rhizobiums, the strain S27 proved efficient against the soil borne pathogen in vitro and in pot experiments. Our study suggested that inoculation with specific Rhizobium exerts significant disease suppress against R. solani in controlled conditions. © 2011 Academic Journals. Source

Hamed H.,University of Sfax | Gargouri A.,University of Sfax | Hachana Y.,Institute National Dagronomie Of Tunis | El Feki A.,University of Sfax
Small Ruminant Research | Year: 2010

The relationship between milk somatic cell counts (SCCs), differential leukocytes (macrophage, lymphocyte, and PMNs) and the influence of lactation on these parameters in camel's and cow's milk was compared. Milk was separated into milk with SCC≤105cellsmL-1 (group 1) and milk with SCC≥105cellsmL-1 (group 2). Somatic cell counts and differential leukocytes were significantly correlated in both species and the two SCC groups. In group 1, lymphocytes were the predominant cell type in camel's milk and macrophage in cow's milk. In both species, PMNs were useful indicators to define either uninfected or infected state in group 1 and group 2. In camel's milk, PMN numbers were higher immediately after parturition and declined gradually with advanced lactation, while macrophages number increased through lactation. In cow's milk, PMNs were the dominant cell type at the beginning of the lactation and tended to maintain high levels as lactation progressed. Our results suggest that in some aspects the immune system of camels mammary gland differs from that of bovine. © 2010 Elsevier B.V. Source

Ghazghazi H.,Institute National Dagronomie Of Tunis | Miguel M.G.,University of Algarve | Miguel M.G.,University of Lisbon | Hasnaoui B.,Institute Sylvo Pastoral | And 5 more authors.
African Journal of Biotechnology | Year: 2010

The antioxidant activity of leaf extracts of Rosa canina from diverse localities of Tunisia were evaluated by ABTS and DPPH methods, whereas in those of essential oils and carotenoids extracts such activity was determined only by the ABTS method. Total phenols determined by the Folin method revealed that at Aindraham, samples showed a great variability of phenol content in contrast to those from Feija. After chemical analysis of the essential oils by gas chromatography (GC) and gas chromatography coupled to mass spectra (GC-MS), revealed that the oils of Feija were predominantly composed of palmitic acid, vitispirane, linoleic acid, lauric acid, myristic acid and phytol acetate, while in those samples from Aindraham predominated vitispirane, palmitic acid, linoleic acid and phytol acetate. Higher concentrations of β-carotene and lycopene were found in the samples from Aindraham after determination by high performance liquid chromatography (HPLC). All samples possess antioxidant activity, nevertheless much more significant in phenol extracts in contrast to the carotenoid extracts, which possess the lowest activity. © 2010 Academic Journals. Source

Neila A.,French National Institute for Agricultural Research | Neila A.,University of Carthage | Adnane B.,French National Institute for Agricultural Research | Mustapha F.,Equipe de Biotechnologie vegetale et Agrophysiologie des symbioses | And 7 more authors.
Journal of Plant Nutrition | Year: 2014

Five north Tunisian native rhizobia were tested in symbiosis with 'Coco-blanc' variety under two phosphorus (P) supplies [P-sufficient and insoluble P (IP)] at 250 μmol P plant-1. At flowering stage, responses against IP were assessed and indicated that inoculation with P.Ps.09 produced a high nodule biomass (0.12g). Similarly, P.Tb.09 produced 0.08 g nodule biomass under both P and P.Bj.09 that significantly increased nodule number under IP. Shoot biomass exhibited high dry weight with P.Tb.09 and CIAT899 (1.6 g plant-1). Inoculation with CIAT899 produced a high root biomass under both P. Analysis of a halo diameter of clear zone rounding each colony under IP indicated that P.Tb.09 has developed high halo Ø (1.7cm). These variations were associated under IP with a decrease of pH by P.Ar.09 and with increase in shoot phosphatase activity by P.Ar.09, P.Bj.09, P.OM.09 and P.Ps.09. The use of P-efficient rhizobia may constitute an adaptive mechanism against P-deficiency tolerance.© Taylor & Francis Group, LLC. Source

Imen H.,French National Institute for Agricultural Research | Imen H.,Institute National Dagronomie Of Tunis | Imen H.,Center National des science et des Technologies Nucleaires | Neila A.,French National Institute for Agricultural Research | And 4 more authors.
Journal of Plant Nutrition | Year: 2015

The use of phosphate-solubilising bacteria as inoculants increases plant phosphorus (P) uptake and thus crop yield. Strains from the genus Mesorhizobium are among the most powerful phosphate solubilizing microorganisms. In order to study efficiency in P uptake and N2 fixation in chickpea (Cicer aritenium), forty-two rhizobia strains natively from Tunisian soils were studied in symbiosis with the chickpea variety “Béja1” which is frequently cultivated in Tunisia. Plants were inoculated separately with these strains under controlled conditions in perlite under two sources of P i.e. soluble (KH2PO4) and insoluble P (Ca2HPO4). At flowering stage, growth, nodulation, P uptake and N2 fixation were assessed in all symbiotic combinations. The results showed that the S27 strain efficiently mobilized P into plants, observed as a significant increase of plant P content when insoluble P (Ca2HPO4) was supplied to the soil. This was associated with a significant increase in plant biomass, nodule number and N content under insoluble P conditions. Additionally, inoculation with the Mesorhizobium strain S27 significantly increased the root acid phosphatase activity under insoluble P. This study also shows significant correlations found between plant P content and acid phosphatase activity under low P conditions which may highlight the contribution of acid phosphatases in increasing P use efficiency. A field experiment also showed that most of the chickpea analyzed parameters were improved when plants inoculated with two selected rhizobia strains (S26 and S27) and supplied with P2O5. Overall, these findings postulate that rhizobial inoculation should not only be based on the effectiveness of strains regarding N fixation, but also to other traits such as P solubilisation potential. © 2015, Copyright © Taylor & Francis Group, LLC. Source

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