Abstract
Different sugars and amino acids were added to a conducive soil to study their effects on bacterial wilt of tomato caused by Ralstonia solanacearum YU1Rif43. The compounds were selected mainly based on the utilization ability of the pathogen and added to the soil at application rates of 0.5 to 5 mg g-1, together with an inoculation of the pathogen. While tomato seeds germinated and grew healthy in soils amended with carbohydrates at a rate of 5 mg g-1, most of the seeds failed to germinate in soils to which serine, glycine and alanine were applied at the same rate. At 2.5 mg g-1, the inhibitory effect on tomato germination disappeared except for methionine. Most of the compounds decreased the incidence of wilt during 30 days of cultivation, while sucrose, fructose, threonine, acetate, and glycerol had no apparent suppressive effect. The compounds that showed the most suppressive effect were glucose, proline, glutamine, serine, arginine, and lysine. The pathogen utilized glucose, proline, and glutamine, but not serine, arginine and lysine. Certain compounds stimulated microbial activity and decreased the survival of the pathogen, and thereby suppressed bacterial wilt of tomato.
