Plant growth promoting bacteria characterization

Plant growth-promoting bacteria (PGPB) are associated with many plant species and are commonly present in many environments. The most widely studied group of PGPB are plant growth-promoting rhizobacteria (PGPR) which colonizes the root surfaces and the rhizosphere. Free-living rhizobacteria use some of the mechanisms to promote plant growth and control phytopathogens. The widely recognized mechanisms of biocontrol mediated by PGPB are competition for an ecological niche or a substrate, production of inhibitory chemicals, and induction of systemic resistance in host plants to a broad spectrum of pathogens. Biological control is thus being considered as an alternative or a supplemental way of reducing the use of chemicals in agriculture. There has been many studies describing potential uses of plant associated bacteria as agents stimulating plant growth and managing soil and plant health. Studies so far concentrated on the plant growth promoting features of rhizospherical bacteria of potato, tomato, onion plants. In this study, bacteria were isolated from rhizosphere of some of perennial plants, such as olive trees, walnut trees and apple trees and tested for their plant growth promoting activities. In addition to traditional identification tests, the bacteria were identified by using fatty acid methyl ester (FAME) analysis.