Recent Insights into Iron Uptake by Anabaena sp.Strain PCC7120

As a cofactor in photosynthesis,respiration and nitrogen fixation,iron is essential for cyanobacteria, and iron deficiency would affect the productivity.Iron is present in oxic ecosystems as insoluble iron(Ⅲ) oxide minerals and thus is not readily available for living organisms to acquire and use. Under the iron-limiting conditions,siderophores are exported from the Anabaena cell,where they chelate ferric ions in the environment.Specific ferric-siderophore complexes are recognized by cognate outer -membrane transporters,which initiate the process of iron transport into the cell where the iron becomes available for metabolic functions.Recent progress of siderophores including the types and their biosynthetic pathway was summarized.The components of the putative iron transport system were analyzed. The regulation mechanism of iron uptake was also discussed.This review would provide new evidence for advanced research on iron uptake by Anabaena.