Polyoxins.a group of structurally-related nucleoside antibiotics produced by Streptomyces.cacaoi var.asoensis and Streptomyces aureochromogenes,exhibit powerful bioactivity against phytopathogenic fungi.A gene cluster (pol) essential for the biosynthesis of polyoxin was cloned from Streptomyces cacaoi.From 46.066-bp sequenced region,20 out of 39 of the putative ORFs were defined as necessary for polyoxin biosynthesis as evidenced by its production in a heterologous host.Streptomyces lividans TK24.