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Etiology

Induction of Outgrowth Formation on Storage Roots of Sweet Potato due to Plant Pathogenic Bacteria. M. Goto, Professor of Plant Pathology, Shizuoka University and Plant Pathologist of Seibu Plant Protection Office, 422 Shizuoka, Japan; T. Makino, Faculty of Agriculture, Shizuoka University and Plant Pathologist of Seibu Plant Protection Office, 422 Shizuoka, Japan. Phytopathology 66:28-33. Accepted for publication 6 August 1975. DOI: 10.1094/Phyto-66-28.

Storage roots of sweet potato (Ipomoea batatas) formed outgrowths in cambium regions after inoculation with plant-pathogenic bacteria as well as some bacteria isolated from the plant rhizospheres. The outgrowths developed not only from the normal vascular cambium regions, but also from anomalous cambium regions. The size of outgrowths differed depending on the bacterial species inoculated, and also on the size of sweet potato slices. The most striking outgrowths were produced by bacteria in the Pseudomonas syringae group and several other plant pathogens. The corynebacteria, agrobacteria, and several saprophytic bacteria were either ineffective or produced very weak reactions. The outgrowths were not formed when the inoculated slices were either treated with streptomycin within 6 hours, washed with distilled water prior to inoculation, or left noninoculated for longer than 3 hours.