DIVERSITÉ PHÉNOTYPIQUE ET PROPRIÉTÉS PGPR DES RHIZOBIA NODULANT L'ARACHIDE (Arachis hypogaea L.) CULTIVÉE DANS LES SOLS SABLEUX ALGÉRIENS

Abstract

In order to assess phenotypic variability of native rhizobia nodulating peanut (Arachis hypogaea L.), a collection of fourteen isolates obtained from effective root nodules of peanut, cultivated in two potential regions of Algeria (Sebseb and EL Mansoura), was subjected to phenotypic characterization using morphological, biochemical and physiological tests. Some Plant Gowth Promoting Rhizobacteria (PGPR) properties had also been investigated in this study for each strain. Furthermore, a representative strain (M044713), forming a separate cluster in the UPGMA dendrogram of API 20NE tests was chosen for phylogenetic analysis using 16S rRNA gene. The results showed that most of bacterial isolates are Gram-negative bacilli. They can be divided into slow-growing and fast-growing rhizobia. Their responses to the various tests as well as their PGPR characteristics were interesting, but variable. The phylogenetic distribution of the isolate M044713, based on 16S rRNA sequence analysis, revealed low similarity percentages with all strains previously isolated from peanut and the most important percentage of similarity was 94.5%, noted with Pseudoxanthomonas koreensis species