Phenotypic and molecular characterization of plant growth promoting Rhizobacteria isolated from the rhizosphere of wheat (Triticum durum Desf.) in Algeria

Abstract

Several strains were isolated from rhizosphere of wheat in Eastern Algeria. All the 10 strains (Azo4, Azo5, Azo6, Azo7, Azo8, Azo10, S1, S2, S3 and S9) were identified; based also on the characteristics which are not only morphological, characteristics such as shape but physiological ones: optimal temperature, pH optimum and NaCl tolerance. These isolates were screened in vitro for their growth promoting traits like production of indole acetic acid (IAA), ammonia (NH 3 ) and solubilize phosphate. The bacterial strains have an optimum growth pH equal to 6.8; in a broad temperature range (28 and 37°C). The molecular identification was done by simple PCR to amplification for 16S rDNA gene using primers AZ16S-D. Some strains (Azo4, Azo5, Azo6, Azo7, Azo8 and Azo10) have high identity with genus Azospirillum which indicates that these isolates belong to the Azospirillum genus, specially to species of Azospirillum brasilense A nested PCR approach performed with degenerate primers was used to amplify nifH gene fragments from the bulk DNA. The amplification product bands at the expected nifH gene fragment size are about 370 bp. Some isolates (S1, S2, S3, Azo4, Azo5, Azo6, S9 and Azo10) were considered by the nitrogen-fixing gene nifH detection of their genome. We managed to highlight the contribution between A. brasilense and durum wheat with inoculation experiments performed under greenhouse conditions showed that all A. brasilense (six strains) have a good report for growth of roots and plants and improve the production of durum wheat (Triticum durum var: GTA). These data demonstrate the importance of the test especially in programs to improve the quality of wheat in Algeria.

Study of Endophytes as Biocontrol Agents Vis-a-Vis their Compatibility to Fungicides in Grapes

“…Antagonistic activity of endophytic bacteria mostly depended on the secretion of different hydrolytic enzymes (Compant et al, 2005). Yasmin et al (2010) demonstrated that when isolates produced clear zones, they are phosphate solubilizers but the studied isolates did not exhibit any phosphate solubilising capacity.…”

Morpho-Physiological and Biochemical Characterization of Soybean-Associated Rhizobia and Effect of Their Liquid Inoculant Formulation on Nodulation of Host Plants in the Cameroon Cotton Fields Zone

“…Ammonia production by rhizobia isolates was assessed on 0.5 mL Peptone broth medium (1 g peptone, 0.5 g NaCl, 0.5 g potassium nitrate, and 1000 mL distilled water), dispersed in each labelled test tubes with a control. Following incubation for 3 days, 1 mL of Nessler's reagent was added to each of the rhizobia culture in the test tubes, then development of color from orange to brown was recorded as an indication of the presence (+) of ammonia [16]. The qualitative analysis of Indole Acetic Acid (IAA) production by rhizobia isolates was carried out in tubes culture in each of which was added 50 μg/mL filtered tryptophan broth solution.…”