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用转座子Tn5插入诱变法获得了水稻白叶枯病菌的35个致病相关基因突变体及其致病性和生化表型的多效性变化。用一个毒性基因突变体(XcoM 3105)中被Tn5插入失活的基因片段作为探针,从病菌粘粒基因文库中分离出8个毒性基因克隆。其中一个克隆(pNAX3103)不仅决定了病菌对寄主水稻的致病性(毒性)和非寄主烟草的致敏性,而且可能与淀粉酶基因存在着负调节关系。该克隆片段具有增加病菌不同小种的毒性和扩大寄主范围的正向功能。它在病菌不同小种或菌系菌株以及其它几种主要植物病原细菌中具有序列同源性。
A total of 35 pathogenicity-related mutants and their pleiotropic and biochemical phenotypic changes were obtained from the transposon Tn5 insertion mutagenesis. Eight virulence gene clones were isolated from the gut cosmid library of a virulence gene mutant (XcoM 3105) using a fragment of the inactivated gene inserted into Tn5 as a probe. One of the clones (pNAX3103) not only determined the pathogenicity (virulence) of the pathogen to the host rice and the sensitization of the non-host tobacco, but also had a negative regulatory relationship with the amylase gene. The cloned fragment has the positive function of increasing the toxicity of different races of bacteria and expanding the host range. It has sequence homology among different races or strains of bacteria and several other major plant pathogenic bacteria.