VIEW ARTICLE

Interaction between Xanthomonas phaseoli, Xanthomonas vesicatoria, Xanthomonas campestris, and Pseudomonas fluorescens in Bean and Tomato Leaves. Shih -Tien Hsu, Graduate Student, Department of Plant Pathology, Cornell University, Ithaca, New York 14850, Present address of senior author: Department of Plant Pathology, National Chung Hsing University, Taichung, Taiwan, Republic of China; Robert S. Dickey, Professor, Department of Plant Pathology, Cornell University, Ithaca, New York 14850. Phytopathology 62:1120-1126. Accepted for publication 5 April 1972. DOI: 10.1094/Phyto-62-1120.

Streptomycin-resistant mutants were used to differentiate between two bacterial species growing together in the same leaf tissue after inoculation by the injection-infiltration method. In bean leaves, prior inoculation (4 days) with Xanthomonas phaseoli stimulated the growth of Xanthomonas vesicatoria and Xanthomonas campestris, but not Pseudomonas fluorescens. The population of X. phaseoli was decreased, whereas the population of X. vesicatoria was increased when bean leaves were inoculated simultaneously with mixtures of the two pathogens; prior inoculation (4 days) with X. vesicatoria, X. campestris, or P. fluorescens reduced the growth of X. phaseoli. Similarly, in tomato leaves, prior inoculation (2 days) with X. vesicatoria enhanced the growth of X. phaseoli and X. campestris, but not P. fluorescens. The population of X. vesicatoria was decreased, whereas the population of X. phaseoli was increased when tomato leaves were inoculated simultaneously with the mixtures of the two pathogens; prior inoculation (2 days) with X. phaseoli, X. campestris, or P. fluorescens reduced the growth of X. vesicatoria. Prior inoculation of bean leaves with P. fluorescens and of tomato leaves with P. fluorescens or X. phaseoli delayed the development of symptoms caused by X. phaseoli and X. vesicatoria, respectively.