The ever increasing global population entails the need for uplifting agricultural productivity which is laden with hindrances such as crop nutritional deficiencies and diseases. Extensive use of chemical fertilizers and pesticides in overcoming these hurdles has come with a cost of irreparable damage to the environment and human health. As such, plant growth promoting rhizobacteria (PGPR) offers promise for establishing environment friendly sustainable agriculture systems and as a notable alternative to these harmful chemicals due to their wide range of direct and indirect mechanisms of plant growth promotion. In this review we focus on the indirect mechanisms, which involve plant growth promotion through disease suppression. Disease suppression mechanisms include antibiosis, Induced Systemic Resistance (ISR), high affinity siderophore production, competition for nutrient and niches and production of lytic enzymes. Disease suppression roles of these mechanisms have been illustrated in different strains of PGPR. Based on experimental evidences, PGPR, mostly Bacillus and Pseudomonas strains have been used as biocontrol agents as they demonstrate wide range of protection in a variety of plants. PGPR have huge prospects for use in eco-friendly sustainable agriculture for plant protection from a myriad of plant diseases.
