Plant diseases cause economical loss of billions of dollars by reducing crop yield, lower produce quality and contaminating food grain with toxic chemicals. The endless variety and complexity of the many diseases of plants caused by fungi have led to the development of a correspondingly large number of fungicides; unfortunately several plant pathogens have developed resistance to certain fungicides. Another approach is to apply genetically resistant cultivars, but this is not viable after a few years. The present review highlights the role of PGPR strains, specifically referring to allelochemicals produced and molecular mechanisms. Further research to fine tune combinations of allelochemicals, plant-microbe–pathogen interaction will ultimately lead to better disease control.
