Siderophore production by plant growth promoting microorganisms

Under iron limiting conditions, many bacteria secrete ferric iron-specific ligands, generically termed siderophore, which aid in sequestering and transport of iron. We report here the production of siderophore by selected plant growth promoting microorganisms. Production of siderophore by plant growth promoting microorganisms were detected via the chrome azurol S assay, a general test for siderophore detection, which is independent of siderophore structure. Eight bacterial isolates having better plant growth promoting traits were evaluated for siderophore production in laboratory among the isolates Pseudomonas flurescens was noted to 75 per cent siderophore production followed by Azospirillum lipoferum (67 per cent). However, Rhizobium phaseoli found to have no colour change and no siderophore production in CAS agar test.