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2015年,在广东省广州市番茄种植区发生番茄髓部坏死病,从番茄病样中分离到一种细菌。随机选取5株细菌进行致病性测定,结果显示,这5株细菌均可侵染番茄植株产生典型的髓部坏死症状,与田间病株的症状相同。5株细菌的16S rDNA序列间同源性为99.9%~100%,且与菊苣假单胞菌(Pseudomonas cichori)MAFF211996、TIs01和IP1-05菌株的16S rDNA序列同源性最高,为99%。利用菊苣假单胞菌hrcR基因的特异引物Hrp1a/Hrp2a进行PCR,从这5株细菌的DNA中均能扩增出大小约897 bp的特异片段;这些片段序列间同源性为99%~99.9%,且与P.cichori 83-1菌株hrcR基因的序列同源性为99.9%。这些结果表明,引起广东番茄髓部坏死病的病原为菊苣假单胞菌(P.cichorii)。生理生化试验显示,该病原菌与文献报道的菊苣假单胞菌的生理生化特征均相吻合,进一步证实引起广东番茄髓部坏死病的病原为菊苣假单胞菌。
In 2015, tomato marrow necrosis occurred in tomato-growing areas in Guangzhou, Guangdong Province, and a bacterium was isolated from tomato-like samples. Five strains of bacteria were randomly selected for pathogenicity test. The results showed that all five strains of bacteria could infect tomato plants to produce the typical symptoms of myeloproliferative necrosis, which were the same as those in the field. The 16S rDNA sequences of 5 isolates shared 99.9% -100% homology with 16S rDNA sequences of 99% homology with Pseudomonas cichori MAFF211996, TIs01 and IP1-05 strains. The specific primers Hrp1a / Hrp2a of Pseudomonas cichorii hrcR gene were used to amplify the specific fragment of about 897 bp in length from the DNA of these 5 strains of bacteria. The homology between these sequences was 99% ~ 99.9 %, And the sequence homology with the hrcR gene of P.cichori 83-1 strain was 99.9%. These results indicate that the causative agent of necrosis of the myeloid pod of Guangdong tomato is P. cichorii. Physiological and biochemical tests showed that the pathogen was consistent with the physiological and biochemical characteristics of Pseudomonas cichorii reported in the literature, further confirmed that the cause of necrosis in Guangdong tomato pus was Pseudomonas cichorii.