Influence of iron and antibiotic effect produced by rhizobacteria from tea(Camellia sinensis) plantations

Two rhizobacterial Pseudomonas strains (RRLJ30 and RRLJ17), isolated from tea plantations, produced siderophores in iron deficient media and inhibited several plant pathogenic fungi in vitro. Iron reduced both siderophore production and fungal inhibition. Purified siderophores from both the strains inhibited Fomes lamoensis, a common pathogen on tea. Siderophores from 2 organisms were hydroxamates, carboxylates and catecholates. HPLC analysis of one of the organisms (RRLJ30) showed 4 peaks, of which one showed an iron chelating antifungal property. The active fraction had a mass unit of 1091. Amino acid analysis revealed D-Ala, L-Ala, Gly, L-Ser, L-Asp and L-Glu as the main amino acids. RRLJ17 induced plant growth vigour in Phaseolus vulgaris and Camellia sinensis when introduced as bacterial inoculants on seeds and cuttings, respectively.