Biochemical Studies of the Host-Parasite Relationship between Xanthomonas oryzae and Rice Plant

1. The utilizations of inorganic sulfur sources in seven strains of Xanthomonas oryzae and other five species belong to Xanthomonas were investigated.2. Although sulfur containing amino acids were required for the rapid growth of seven strains of Xanthomonas oryzae and Xanthomonas citri, it was observed that these bacteria utilize inorganic sulfate after prolonged latent period which may require for adaptive formation of the sulfate reducing enzyme system.3. No marked difference in pathogenicity has been observed when the cells prepared with either the complete medium or the synthetic basal medium containing sodium sulfate were inoculated to rice plant leaves.4. No direct relationship between the ability of utilizing inorganic sulfate, requirement of sulfur containing amino acids and pathogenicity and/or lysotype on bacteriophage was observed in seven strains of Xanthomonas oryzae.5. Xanthomonas malvacearum, Xanthomonas phaseoli, Xanthomonas pruni and Xanthomonas vesicatoria utilized extensively inorganic sulfate as a sole sulfur source.6. The utilization of inorganic sulfate in Xanthomonas citri, Xanthomonas oryzae and Xanthomonas pruni were promoted by the presence of nicotinic acid amide in the medium.