魔芋软腐病菌分子鉴定与遗传多样性

通过对分离的魔芋软腐病菌株和其它参试菌株的致病性测定、选择性培养基培养性状观察和16S-23S rDNA转录间隔区PCR(ITS-PCR)分析,将测试的33株软腐病菌株主要分为3个组群。第1组群为胡萝卜软腐欧文氏杆菌胡萝卜软腐亚种(Erwinia carotovorasubsp.carotovora,E.c.c.);第2组群为菊欧文氏杆菌(Erwinia chrysanthemi,E.ch.);还有一组未能确定的菌株。利用细菌基因组重复序列通用引物BOX和J3进行Rep-PCR特异性扩增,引起软腐病的菌株E.c.c.和E.ch.(ITS-PCR鉴定)种内的Rep-PCR指纹存在明显的遗传分化,经聚类分析,在0.1水平上把E.c.c.13株区分为5个类群。

Molecular identification and genetic diversity in Konnyaku's soft rot bacteria

The soft rot bacteria Erwinia are an important pathogens of konnyaku and other ornamental plants.Thirty-three strains were isolated from soft-rotted konnyaku and other ornamental plants.According to the characteristics of pathogenicity and culture character on semi selective medium(crystal violet pectate,CVP),most of strains tested caused rotten symptom in tubers and stems of konnyaku,and characteristic deep cavities were formed on CVP.To amplify 16S-23S rDNA intergenic transcribed spacer(ITS) by PCR and electrophorese through agarose gel,most strains are clustered into two heterogeneous populations of Erwinia carotovora subsp.carotovora,E.c.c.and Erwinia chrysanthemi,E.ch..Besides,several other strains could not be identified into species by ITS-PCR.The characteristic band patterns of E.c.c. and E.ch.could be clearly distinguished by repetitive element-polymerase chain reaction(rep-PCR,BOX and J3 primers).And the fingerprinting of E.c.c.stains were also different from each other.Dendrogram was generated from the data of primer BOX by using UPGMA analysis because the primer BOX was higher resolution than other primers(such as prime J3) for identifying the same intraspecies strains.Strains of E.c.c.were divided into five groups on the 0.1 level of linkage distance.