| dc.description.abstract | Xanfhomonas axompodis pv, glycines (Xag) causes bacterial pustules an susceptible soybean cultivars. Therefore, understanding on the? mechanism of pathogenicity and soybean - Xag interaction are paramount impartant to develop strategy far disease control and as a model system fur a similar phenomenon. The objectives of this work are: (i) to identify pathogenicity gene(s) of Xag as an approach to understand the mechanism underlying specific pathogsnicrty in this group of bacteria, and (ii) to design specific PCR primers for Xag. A non-pathogenic Xag mutant derived from the wild type strain Xag YR32, designated M715, was constructed employing a mini-Tn5 transpusan. We have cloned a 1.8 kb-Pstl DNA fragment from Xag YR32. DNA sequence analysis indicated that the gene inactivated by the transposon in M"7 5 encoded a TonB-dependent receptor which is invofved in uptake of ferric-siderophore into the cell. Introduction of a broad-host range plasmid harboring a corresponding DNA fragment from the Xag YR32 into MY1 5 restored, albeit partially, pathogenicity of the mutant. We have designed two specific PCR primers for Xag, i.e., EttyOl (5'-TTgCggCgATTg-3') and EttyQ2 (5'- CgCATgCCATTg-3'). Arnpfificatian af Xag genornic DNA employing these specific primers generated a 436-bp amplimn. Southern hybridization analysis of five pathavars of Xanfhomonas and five wild types of Xag from Indonesia and Taiwan indicated that the pathogenicity gene was unique to Xag. | id |
