VIEW ARTICLE

Effect of Halo Toxin-Containing Filtrates of Pseudomonas phaseolicola on the Growth of Bean Callus Tissue. Y. P. S. Bajaj, Research Associate, Department of Botany and Plant Pathology, Michigan State University, Senior author is now Gastprofessor, Botanisches Institut der Universität, 69-Heidelberg, Germany; A. W. Saettler, Research Plant Pathologist, Crops Research Division, ARS, USDA, East Lansing, Michigan 48823. Phytopathology 60:1065-1067. Accepted for publication 16 February 1970. DOI: 10.1094/Phyto-60-1065.

Growth of bean stem-callus tissue was inhibited 77%, 41%, and 10% when 10% (v/v) culture filtrates of Pseudomonas phaseolicola, P. syringae, and P. morsprunorum, respectively, were added to the callus tissue culture medium. Only P. phaseolicola culture filtrates induced halos on bean leaves. P. phaseolicola filtrates diluted 1:10 with water induced no halos. Callus tissue grown in a medium containing 10% (v/v) P. phaseolicola culture filtrate contained more total N, less soluble protein, and a much higher level of ornithine than callus tissue grown in control filtrate. Similarities between the physiological effects of toxin-containing filtrates of P. phaseolicola on bean callus and on green leaf tissue suggest the feasibility of employing callus tissue to study the mode of toxin action.