show Abstracthide AbstractBiopesticides are an attractive biotechnological alternative to conventional pesticides for soil-borne plant diseases. A screening strategy uncovered the Streptomyces rochei strain JK1 as a potent inhibitor of oomycete growth. The JK1 strain suppressed plant diseases caused by major oomycete pathogens. The culture filtrates of the JK1 strain inhibited oomycete growth in plate assays and could suppress oomycete-caused plant diseases. The macrolide secondary metabolite borrelidin was identified using HR-ESI-MS and NMR from growth-inhibitory fractions and inhibited both oomycete growth and plant diseases. The genome of the JK1 strain was used for the analysis of biosynthetic gene clusters (BGCs), of which there were approximately 30 BGCs regions predicted from the genome, including a BGC for borrelidin. The S. rochei JK1 strain is an important new bioresource for the control of oomycete-caused diseases.