Abstract: 【Objective】Fatty acids of different strains of Ralstonia solanacearum (Rs) were detected by using gas chromatography and the polymorphism was analyzed in order to investigate the relationship between the polymorphism of fatty acid and taxonomies of Rs in existence.【Method】Fatty acids of 40 strains of Rs were detected by using gas chromatography. Different Rs strains isolated from the same host plant or from the different host plants were compared with their fatty acid distributions. The fatty acids from 40 strains of Rs were analyzed by cluster analysis and find out the characteristics of fatty acids about these groups, the relationships between the polymorphism of fatty acid and Rs race, biovar type and virulent type were separately investigated. 【Result】The result showed that the polymorphism of fatty acid of strains isolated from the same host plant or from the different host plants was evident based on fatty acid distribution, those 40 strains of Rs could be separated into three groups: group I, group II and group III. No relationship was found between the polymorphism of fatty acid and Rs race or Rs biovar type. But, there was a certain correlation between it and virulent type: group I was avirulent, group III was virulent and the other type was transition-virulent. 【Conclusion】The polymorphism of fatty acid of Rs was evident and there was a certain correlation between it and virulent type. Fatty acid might become a new index for taxonomy of Rs.

Key words: Ralstonia solanacearum, fatty acid, polymorphism, gas chromatogram