首页|rDNA-ITS sequence analysis of pathogens of cucumber downy mildew and cucumber powdery mildew

rDNA-ITS sequence analysis of pathogens of cucumber downy mildew and cucumber powdery mildew

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To determine the pathogens of cucumber downy mildew and cucumber powdery mildew by molecular marker,we amplified and sequenced the rDNA-ITS region of the pathogens of cucumber downy mildew and cucumber powdery mildew collected from the Shanghai region.The intra-/interspecific sequence difference was analyzed by rDNA-ITS sequence.The results show that the length of rDNA-ITS1 and rDNA-ITS2 of cucumber downy mildew's pathogen was 141 bp and 406 bp,respectively,with GC contents of 41.13% in ITS1 and 46.8% (Minhang and Jinshan District,sml and sm2) or 46.55% (Pudong District,sm3) in ITS2.The rDNA-ITS sequence was intraspecific conservation.The interspecific difference was related with their kin relationship.The pathogen of cucumber downy mildew was identified as Pseudoperonospora cubensis by molecular marker.The length of rDNA-ITS1 and rDNA-ITS2 of cucumber powdery mildew's pathogen was 136 bp and 89 bp,respectively,with GC contents being 59.56% and 66.29%,and rDNA-ITS sequence being highly conservative in this study that was the same as Sphaerotheca cucurbitae.But the sequence difference between the strains in the Shanghai region in this study with S.fuliginea was 4.5%,which was identified by morphology.It is suggested that the pathogen of cucumber powdery mildew should be further clarified and determined.

cucumber downy mildew's pathogencucumber powdery mildew's pathogenrDNA-ITS

Na WANG、Yajun MA、Cuiyun YANG、Guanghui DAI、Zhezhi WANG

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Department of Etiologic Biology,the Second Military Medical University,Shanghai 200433,China

Key Technologies Research and Development Program of Shanghai,China

03dz19314

2008

中国农学前沿
高等教育出版社

中国农学前沿

ISSN:1673-7334
年,卷(期):2008.2(3)
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