烟草曲茎病毒Y128分离物及伴随卫星的分子鉴定

Identification of Y128 Isolate of Tobacco Curly Shoot Virus and Associated Satellite DNA Molecule

从云南保山田间表现曲叶症状的烟草植株上分离到病毒分离物Y128,病株在实验室可经烟粉虱(Bemisiatabaci)传播到健康烟草上。分别用针对烟草曲茎病毒(TbCSV)、云南烟草曲叶病毒(TLCYNV)、中国番茄黄化曲叶病毒(TYLCCNV)及泰国番茄黄化曲叶病毒(TYLCTHV)等田间常复合侵染的云南粉虱传双生病毒的特异性引物对Y128DNA-A进行PCR扩增,结果表明Y128是烟草曲茎病毒(TbCSV)的1个分离物。利用DNAβ的特异性引物β01和β02,在Y128中扩增到卫星DNA分子(Y128β)。对Y128进行DNAβ全序列测定及分析表明,Y128β全长1350个核苷酸,其互补链上编码1个有功能的ORF(βC1)。Y128β的全序列与TbCSV各个分离物的卫星分子(Y2β、Y35β和Y115β)的同源性最高,分别为85·2%、94·3%和88%;与其它已报道的卫星DNAβ的同源性均低于56·1%。

Virus isolate Y128 was obtained from tobacco showing leaf curl symptoms in Baoshan, Yunnan province. Y128 is experimentally transmissible to healthy tobacco plants by whitefly （Bemisia tabaci） and induces similar symptoms in field. The PCR amplification, using the specific primers of tobacco curly shoot virus （TbCSV） , tobacco leaf curl Yunnan virus （TLCYNV） , tomato yellow leaf curl China virus （TYLCCNV） and tomato yellow leaf curl Thailand virus （TYLCTHV）, which are WTGs often co-infected in field in Yunnan, proved that virus isolate Y128 is an isolate of TbCSV. Satellite DNA molecule （Y128β） was found to be associated with Y128 by PCR using the primers 1301 and 1302. The complete nucleotide sequence of Y128β was determined. Sequence analysis showed that Y128β consists of 1350 nucleotides, with a functional ORF （βC1 ） in complementary-sense DNA. Y128β has 85.2% , 94.3% and 88% sequence identities with Y2β, Y35β and Y115β associated with TbCSV, respectively, and lower than 56. 1% sequence identities are found with other reported satellite DNA molecules.