Beneficial properties, colonization, establishment and molecular diversity of endophytic bacteria in legumes and non legumes

Different genera of bacteria are present as endophytic in roots and nodules of legumes and roots of non legumes grown in different parts of the world. A number of these endophytic inhabitants vary from few to large numbers. Predominantly, endophytes belongs to three major phyla, Actinobacteria, Proteobacteria and Firmicutes and includes members of Streptobyces, Azocareus, Gluconobacter, Pseudomonas, Serratia, Stenophomonas, Bacillus, Paenibacillus and Enterobacter. Majority of the endophytes show plant growth promotion and have other beneficial traits like enhancement of biological nitrogen fixation, phytohormone production, phosphate solubilization, inhibition of ethylene biosynthesis in response to biotic or abiotic stress and above all have biocontrol activity. These endophytes colonize inside the root or nodules. It seems no host specificity exist between different endophytic bacteria and plant host. These opportunist bacteria can enter the plant tissue whenever they have the opportunity either after dissolving the cell wall or through crack entry. Beneficial effects of bacterization of these endophytes have been shown in different plant host under green house and even under field conditions. Therefore endophytic bacteria are better alternate to sustain crop productivity.