Isolation and identification of a phosphate-solubilizing Paenibacillus polymyxa strain GOL 0202 from durum wheat (Triticum durum Desf.) rhizosphere and its effect on some seedlings morphophysiological parameters

Paenibacillus polymyxa is a common bacterium, belonging to Plant Growth Promoting Rhizobacteria (PGPR). It is found in soils, roots and rhizosphere of various crop plants especially wheat. This bacterium has a great biotechnological potential in sustainable agriculture. Indeed, in the rhizosphere, P. polymyxa is involved in nitrogen fixation, production of phytohormones, exoplysaccharides, hydrolytic enzymes and antibiotics, in the enhancement of soil porosity and in soil phosphorus solubilization. In this study, we have identified GOL 0202 strain as Paenibacillus polymyxa, isolated from durum wheat (Triticum durum Desf.) rhizosphere collected from arid region soil of Southern. This genomic identification was performed by 16S rRNA gene sequencing. It was shown that this strain possesses an interesting phosphate solubilization activity on NBRIP (National Botanical Research Institute Phosphorus) medium containing tricalcium phosphate (Ca-3 (PO4)(2)). This activity, was recorded over five days, it was negatively correlated with pH medium whose decline was due probably to the release of organic acids. In addition to other activities associated with P. polymyxa, this availability of soluble phosphate has allowed the improvement of durum wheat seedlings growth estimated through dry weight, chlorophylls and proteins contents. Hence, P. polymyxa GOL 0202 could be used for their targeted application as bioinoculant.