Integrated Mechanisms of Plant Disease Containment by Rhizospheric Bacteria: Unraveling the Signal Cross Talk Between Plant and Fluorescent Pseudomonas

Being the universal green factories on earth, plants harbor many microbes in the rhizosphere arena. Majority of such free-living microorganisms have a positive effect on plant, known as plant growth-promoting rhizobacteria (PGPR). The PGPR are the extensively studied bacteria which elicit the plant probiotic traits and disease resistance through its competitive dominance in rhizosphere and production of secondary metabolites which act directly or indirectly on plant signaling mechanism. Bacillus and Pseudomonas are the major rhizobacterial members of PGPR group; both are known to exert direct and indirect means of growth promotion on host plant. Although Bacillus have an additional advantage of spore forming nature, majority of the biocontrol negotiators are made of vast Pseudomonas group. Pseudomonas beholds numerous qualities that enable them well suited to function as biocontrol and plant growth-promoting agents in agriculture. The direct mechanism is majorly by phosphate solubilization and release of major growth-promoting hormones. Indirect mechanisms of growth promotion are complex diverse mechanisms, which work individually or together, resulting in imparting probiotic traits. The present review portrays a broad updated understanding of principal mechanisms of Pseudomonas-induced probiotic traits associated with systemic resistance signaling.