Plant pathogenicity in the genus Streptomyces

In this article, we discuss the biology and ecology of plant pathogenic Streptomyces species and the strategies used for management of the diseases they cause. We also consider the role of thaxtomins, a family of phytotoxins, in diseases caused by at least some plant-pathogenic Streptomyces species. Similarities in the effects of these toxins on plants and in the symptoms produced by the pathogens, as well as the correlation between pathogenicity and toxin production, suggest that these compounds are intimately involved in disease development. The effects of thaxtomins on plants and the possibility of a universal target for these toxins in plant cells is addressed. We conclude with a discussion of the questions remaining about plant pathogenicity in the genus Streptomyces, strategies for answering these questions, and the potential for improvements in disease management.