Development of a gene cloning system for Streptomyces hygroscopicus subsp. yingchengensis, a producer of three useful antifungal compounds, by elimination of three barriers to DNA transfer

Streptomyces hygroscopicus 10-22 could not be transformed with any of the commonly used Streptomyces plasmid vectors and was resistant to plaque formation by the Streptomyces phages 4C31 and R4. Repeated selection resulted in the isolation of derivatives ofS. hygroscopicus 10-22 that could be transformed with pIj101-and pJVl-derived cloning vectors and of restriction-deficient derivatives that could accept DNA propagated in Streptomyces lividans 66. These new strains, which include three that still produce the original antibiotics, can be used as hosts for gene cloning. Insertion of nonreplicating vectors by homologous recombination and transposition of Tn4560 were demonstrated in S. hygroscopicus 10-22. Streptomyces hygroscopicus subsp. yingchengensis 5102-6 was discovered in Yingcheng county, Hubei, People's Republic of China (27). Young cultures are yellowish and the spores are grey, becoming black and slimy with age; the spore chains are spirals, and the spore surface is smooth. Colony morphology variants arise spontaneously at a frequency of about 1%. Strain 5102-6 produces three antifungal antibiotics, the first of which is used extensively, with the others used on a small scale, i