Prospection of Plant Growth-promoting Rhizobacterium Enterobacter cloacae and N2-fixing Rhizobium leguminosarum bv. viciae Effect on Faba Bean Evaluation in Sustainable Agriculture

Abstract

Biofertilizers are relying on ecofriendly approaches as sustainability and environmental safety of agricultural for crop production. The multiplicity of beneficial effects of microbial inoculants, particularly plant growth promoters (PGP) and N2-fixing bacteria strengthened to use biofertilizers in modern agriculture. Prospection study of Enterobacter cloacae KX034162 as PGPR was carried out in this study. Based on in vivo assays for PGPRs characterization; Exopolysaccharides production (EPS), biofilm formation, Phosphate, Zinc carbonate and zinc oxide solubilization and productivity of indole acetic acid (IAA) E. cloacae KX034162 was used. The synergistic inoculation effect of two microbial on faba bean (Vicia faba L.) growth parameters and productivity were evaluated in two successful winter seasons. The results showed that the dual inoculation of both microbes have a significant positive effect on the estimated parameters compared with the control. E. cloacae KX034162 produced IAA (47.0 mgl-1), polysaccharides (6.4 gl-1) and solubilized Zn. The dual inoculation enhanced nutrients absorption, nodulation, growth parameters, N% (it was 1.42 and 1.44 in the first and second season compared with 0.29 and 0.30 as un-inoculated treatments, respectively) and at the end faba bean production increased.