Abstract
A potato tuber disk assay of culture broths which had been confirmed to show neither antibacterial nor phytotoxic activity resulted in the discovery of a novel type of crown gall formation inhibitors, julimycin B-II and julichrome Q1.3. These two bisanthraquinones, products of Streptomyces sp. TM-71, inhibited crown gall formation on potato tuber disks at a minimum inhibitory dose of 1.6μg/disk without affecting the growth of Agrobacterium tumefaciens or the germination of alfalfa seeds.
