Please wait a minute...
Frontiers of Agriculture in China

ISSN 1673-7334

ISSN 1673-744X(Online)

CN 11-5729/S

Front. Agric. China    2008, Vol. 2 Issue (3) : 317-320     DOI: 10.1007/s11703-008-0061-z
rDNA-ITS sequence analysis of pathogens of cucumber downy mildew and cucumber powdery mildew
YANG Cuiyun, DAI Guanghui, WANG Zhezhi, WANG Na, MA Yajun
Department of Etiologic Biology, the Second Military Medical University
 Download: PDF(74 KB)   HTML
 Export: BibTeX | EndNote | Reference Manager | ProCite | RefWorks
Abstract 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, sm1 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.
Issue Date: 05 September 2008
 Cite this article:   
YANG Cuiyun,DAI Guanghui,WANG Zhezhi, et al. rDNA-ITS sequence analysis of pathogens of cucumber downy mildew and cucumber powdery mildew[J]. Front. Agric. China, 2008, 2(3): 317-320.
1 Chen G Q, Han S J, Lai Y Q, Yu Y N, Zheng R Y, Zhao Z Y (1987). Flora Fungorum Sinicorum, Vol. 1, Erysiphales.Beijing: Science Press, 78, 316 (in Chinese)
2 Hirata T, Cunnington J H, Paksiri U, Limkaisang S, Shishkoff N, Grigaliunaite B, Sato Y, Takamatsu S (2000). Evolutionary analysisof subsection Magnicellulatae of Podosphaera section Sphaerotheca (Erysiphales) based on the rDNA ITS sequenceswith special reference to host plants. Canadian Journal of Botany, 78: 1521–1530.
3 Kiss L, Cook R T A, Saenz G S, Cunnington J H, Takamatsu S, Pascoe I, Bardin M, Nicot P C, Sato Y, Rossman A Y (2001). Identificationof two powdery mildew fungi, Oidium neolycopersici sp. nov. and O. lycopersici, infectingtomato in different parts of the world.Mycological Research, 105(6): 684–697.
4 Motoaki K, Takashi T (1995). Phylogenyof Alternaria fungi known to producehost-specific toxins on the basis of variation in internal transcribedspacers of ribosomal DNA. Current Genetics, 28: 491–498.
5 Qiu W F (1979). Agricultural Plant Pathology. Beijing: Agricultural Press, 465 (inChinese)
6 Takamatsu S, Hirata T, Sato Y (1998). Phylogenetic analysis and predictedsecondary structures of the rDNA internal transcribed spacers of thepowdery mildew fungi (Erysiphaceae). Mycoscience, 39: 441–453.
7 Takamatsu S, Hirata T, Sato Y (2000). A parasitic transition from treesto herbs occurred at least twice in tribe Cystotheceae (Erysiphaceae):evidence from nuclear ribosomal DNA. MycologicalResearch, 104: 1304–1311.
8 Tetsuya H, Susumu T (1996). Nucleotidesequence diversity of rDNA internal transcribed spacers extractedfrom conidia and cleistothecia of several powdery mildew fungi. Mycoscience, 37: 283–288.
9 Voglmayr H (2003). Phylogenetic relationships of Peronospora and related genera based on nuclear ribosomalITS sequences. Mycological Research, 107(10): 1132–1142.
10 Wei J C (1979). Fungi Identification Notebook. Shanghai: Shanghai Scientific &Technical Publishers, 49 (in Chinese)
11 White T J, Bruns T, Lee S, Taylor J (1990). Amplification and direct sequencing of fungal ribosomal RNA genesfor phylogenetics. California: Academic Press, 315–321
12 Yi J P, Tao T D, Pan L W, Shen Y F, Yin L P, Zheng J Z (2002). Direct detection of Tilletiaindica teliospores by nest PCR. Plant Quarantine, 16(4): 197–200 (in Chinese)
Full text