7 - Biocontrol potential of plant growth-promoting rhizobacteria (PGPR) against Ralstonia solanacearum: Current and future prospects

Abstract

Plant growth-promoting rhizobacteria (PGPR) naturally inhabit the rhizosphere and increase their growth and yield. PGPR have attracted special attention for their ability to enhance productivity, sustainability, and profitability when food security and rural livelihood are a key priority. Studies on PGPR have attained more and more scientific attention in recent decades. PGPR play an essential role in helping plants to establish and grow in nutrient deficient conditions. In recent days, an increasing number of PGPR stains are being commercialized for various crops. The potentiality of PGPR can decrease the global dependence on hazardous agricultural chemicals which destabilize the agro ecosystems. A different mechanism of action has been reported to promote plant growth. Biocontrol mechanisms involved in pathogen suppression by PGPR include substrate competition for iron, nutrients, and space, antibiotic production, lytic enzymes production, hydrogen cyanide, volatile compounds, and induced systemic resistance in host. Biocontrol agents promote plant growth directly or indirectly, either by releasing plant growth regulators (production of indole acetic acid, gibberellins, cytokinins, and ethylene) or other biologically active substances and uptake of nutrients through fixation and mobilization. Current advancement in our understanding of their action mechanisms, colonization ability, diversity, formulation, and application should facilitate their development as reliable components in the management of sustainable agricultural systems. In this chapter, an understanding of the different mechanisms of action of PGPR, control of bacterial wilt, and their significance in crop production is summarized and discussed.