Anthranilic Acid, a Spore Germination Inhibitor of Phytopathogenic Streptomyces sp. B-9-1 Causing Root Tumor of Melon

Abstract

A spore germination inhibitor was isolated from the liquid-cultured material of Streptomyces sp. B-9-1, the causal organism of root tumors in melon, and identified as anthranilic acid, which reversibly inhibited spore germination, showed no effect on hyphal growth, and was effective for other Streptomyces spp. However, anthranilic acid showed an IC₅₀ at ca. 50 μg/ml, and its content in spores was 0.16 μg/9×10⁸ spores, indicating that its contribution to the inhibition of spore germination was small.