PGPR-mediated systemic resistance for sustainable agriculture

Abstract

Bacteria which are shown to have potential for biocontrol of destructive diseases are distributed in many genera. Among them, fluorescent pseudomonads are currently considered as the most effective bacteria for biological control of soil and foliar diseases. Fluorescent pseudomonads enhance the plant growth parameters, and hence, they are called plant-growth-promoting rhizobacteria (PGPR). Fluorescent pseudomonads associated with plants include Pseudomonas fluorescens, P. putida, P. aeruginosa, and P. aureofaciens. PGPR are known to control a wide range of phytopathogens like fungi, bacteria, viruses, insect pests, and nematodes, and they are known to control these pathogens by biocontrol mechanism which may be by competition or antagonism, induction of systemic resistance by these bacteria in the host plant, thereby containing the invading pathogens. Many of the fluorescent pseudomonads, predominantly P. fluorescens, have been isolated from suppressive soil for the management of soilborne and foliar diseases. Several studies have indicated that fluorescent pseudomonads induce systemic resistance against many pathogens and control diseases caused by them. Hence, fluorescent pseudomonads have lot of potential as biocontrol agent for the management of soilborne and foliar diseases of crop plants.