Antibiosis of Siderophore Producing Bacterial Isolates against Phythopathogens and Their Effect on Growth of Okra

The rhizosphere is the narrow region of soil that is directly influenced by root secretions and associated with soil microorganisms. Such bacteria which can grow in the rhizosphere region as well as plant roots and enhance the plant growth are referred as plant growth promoting rhizobacteria (PGPR). Plant Growth Promoting Rhizobacteria promotes growth of plants through direct and indirect mechanisms. In direct mechanism it facilitates nutrient uptake, nitrogen fixation, phosphorus solubilization, siderophore production, IAA and other growth hormone production (Glick, 1995). Indirect mechanisms are control of phytopathogenic microorganisms which are a major and constant threat to sustainable agriculture and environment stability through production of antibiotics, siderophore, lytic enzymes. Application of Plant growth promoting rhizobacteria is a promising environmental friendly approach to obtain sustainable fertility of the soil and plant growth indirectly.