Réponses morphologiques, biochimiques et effets PGPR chez quelques isolats rhizobiens nodulant l'arachide (Arachis hypogaea L.)

Abstract

The aim of this study is the growth promotion and yield enhancement of peanut in the Ghardaia province, 14 isolates were obtained from root nodules of the of Arachis hypogaea L. collected from three localities of same Ghardaia. The 14 isolates were subjected to a phenotypical characterization through a morphological, biochemical and physiological study followed by a numerical analysis. The study on the inoculation of peanut by 14 isolates was carried out for the purpose to assess the ability of nodule formation in isolates and to estimate the positive impact of plant growth promoting rhizobacteria (PGPR) in peanut growth and development. Therefore, the effectiveness of these isolates is related to the characterization of multiple PGP activities like the production of IAA (indole acetic acid), hydrogen cyanide (HCN), siderophores, phosphate and potassium solubilization, and enzymatic activity. All 14 isolates (Bacillus and Cocci to Gram + and Bacillus to Gram -) showed production of AIA and phosphate solubilization. As well as 10 of these isolates showed production of siderophore. For the other activities, isolates have exhibited a variability of the production. The M4 isolate identified by sequencing the DNAr 16 S gene, showed a similarity of 94.06% to Pseudoxanthomonas koreensis.