Production of Catechol-Type of Siderophores by Rhizobium Strains from Sesbania sesban (L.) Merr.

Twenty six Rhizobium strains isolated from ischolar_main nodules of Sesbania sesban (L.) Merr. were studied for their ability to produce siderophores. Of them, only nine strains have the ability to produce catechol-type of siderophores in culture after 4 h of incubation and at neutral pH. Mannitol and sucrose at the concentration 2% stimulated growth and siderophore production. Among nitrogen sources, arginine and proline stimulated growth and siderophore production. Maximum amount of siderophores was produced by SSR 19. 2, 3-dihydroxy benzoic acid (DHBA) was present in siderophore extract of this strain. Arginine and proline were identified as conjugated amino acids of the siderophore. The outer membrane protein profiles of the SSR 19 grown in iron containing medium revealed the presence of single protein band of molecular mass 40 K Da.