Streptomyces griseoruber AL7 has been shown to display strong bioactivity against various plant pathogenic fungi and bacteria.The Escherichia coli was modified to clone host XL1-Blue MR to yield LP3,a new cloning host strain holding a Dcm DNA methylation deficient mutation and the conjugation helper plasmid pUZ8002.LP3 was used to construct the S.griseoruber AL7 genomic cosmid library with an average insert size of 40 kb.The cosmid library was then transformed into S.lividans TK24 via high-throughput conjugation to yield a heterologous expression library.A few expression clones with interesting phenotype were obtained,such as bald phenotype,precocious antibiotic production phenotype,precocious sporulation phenotype and so on.