Plant Growth Promoting Rhizobacteria (PGPR): A Bioprotectant bioinoculant for Sustainable Agrobiology. A Review

Abstract

Plant growth promoting rhizobacteria (PGPR) involves the utilization of large array of soil bacteria to improve yield and plant growth. As free living and symbiotic rhizobacteria, PGPR colonizes extracellular and/or intracellular rhizoenvironment in search for carbon source while indirectly aiding plant growth. In the past few decades, focus has been on developing a biosafety agro base approach void of continuous burden on soil micro flora as a result of agrochemical application. However, with clear understanding of PGPR mechanisms of action; (i) biofertilization (ii) biostimulation (iii) and biocontrol, it create more hope on the possibility of curbing food insecurity, clean environmental sustenance and lower public health risk. Seeds or soil application of PGPRs inoculant enhances directly phosphates solubilization, atmospheric nitrogen fixation and secretion of plant hormones (indole acetic acid, gibberellins, cytokinins and ethylene) needed for growth and adaptation in stressed environment. As soil pathogen consistently rival the roles of these organisms, they (PGPRs)have developed over time wide spectrum of strategies in the form of systemic resistance, iron, space and nutrient competition, antibiotics synthesis, lytic acid production and hydrogen cyanide for efficient food productivity. In view of this, the review widen our scope on the use of PGPR as bioinoculant in sustainable agro practice and to serve as a wakeup call for it reception and implementation in the tropics where paucity of data on it use has long prevailed.