Analisis Sekuen DNA yang Terlibat dalam Patogenesitas dan Perancangan Primer PCR Spesifik untuk Xanthomonas axonopodis pv. glycines

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.