Siderophores are low molecular weight iron chelating secondary metabolites synthesized by various groups of microorganisms help in scavenging iron-limited conditions. Siderophores produced by endophytic bacteria facilitate the plant growth by providing iron to plants. The objective of this study was to isolate and screen the siderophore producing endophytes from nodules and roots of Cicer arietinum and Pisum sativum plants. Out of total eighty four isolates, only 14 endophytes produced siderophore and quantitative analysis was also done. Ten best siderophore producers (above 65% siderophore units) were characterized for the type of siderophore produced. Most of them were producing hydroxamate and carboxylate type of siderophores. These ten isolates were evaluated for other plant growth promoting (PGP) traits invitro. All of them were producing ammonia and IAA. Isolate CPFR10 was found to be positive for all the PGP traits viz. ammonia, organic acid, HCN and IAA production. Diversity analysis of these ten isolates using ARDRA (Amplified rDNA Restriction Analysis) profile revealed nine haplogroups at 90% similarity.
Key words: Endophytes, plant growth promotion, siderophore, CAS assay, tetrazolium, hydroxamate