Structure, Function, and Biosynthesis of Siderophores Produced by Streptomyces Species

Since the natural supply of iron is low, microorganisms acquire iron by secreting siderophores. Streptomyces is known for its abundant secondary metabolites containing various types of siderophores, including hydroxamate, catecholate, and carboxylate. These siderophores are mainly synthesized through the nonribosomal peptide synthase (NRPS) and non-NRPS pathways and are regulated by ferric uptake regulator and diphtheria toxin regulators. Although both NRPS and non-NRPS pathways adenylate substrates, they differ significantly in the catalytic logic. Siderophores produced by Streptomyces play important roles in fields of agriculture, medicine, and environment. However, their structure, function, and synthetic mechanisms have been inadequately summarized. Therefore, this Review aimed to provide an overview of the classification, structure, biosynthesis, regulation, and applications of siderophores produced by Streptomyces. Finally, the need for a comprehensive and well-defined mechanism for synthesizing siderophores from Streptomyces was highlighted to further promote their commercialization and application in agriculture, medicine, and other areas.