茄假单胞菌寄主花生特异性毒性基因的定位

通过对从茄假单胞菌中克隆的pGX1252进行亚克隆分析，发现含pGX1252右边4.5kbKpnI/EcoRI片段的亚克隆pGX1404仍象pGX1252一样能使对花生不致病菌株T2014在花生上致病.用转座子Tn5-loc对pGX1404进行了饱和插入诱变，一共分离得到6个在pGX1404上不同位置的独立插入突变，其中离pGX1404右末端约1.4kb、2.2kg的两个Tn5-loc插入使pGX1404丧失了扩大T2014寄主范围的能力，证实hsv基因位于pGX1404的右边.

LOCALISATION OF THE HOST PEANUT SPECIFIC VIRULENCE GENE(S) OF RALSTONIA

Subcloning analysis of pGX1252 found that 4.5kb KpnI/EcoRI fragment on its right side (pGX1404) still retained the ability of pGX1252 to extend the host range of nonpathogenic potato strain T2014 to include peanut. Plasmid pGX1404 was saturatedly mutated with transposon Tn5lac and six independent insertions of transposon on the insert of pGX1404 were isolated. Two Tn5lac insertions, which were ca.1.4 kb and 2.2 kb away from the right hand end of pGX1404, had made it lose the ability to extend the host range of T2014, indicating that hsv gene(s) was on the right side of pGX1404. The Tn5lac of these two mutants of pGX1404 were markerexchanged to the chromosome of the starting pathogenic strain T2015 generating mutants T2134 and T2135, respectively. Plant tests revealed that the virulence of T2134 and T2135 on peanut was significantly lower than that of T2015, confirming that the transposon disrupted gene(s) of pGX1404 was peanut specific virulence gene.