侵染广西烟草的中国番茄黄化曲叶病毒及其伴随的卫星DNA分子的基因组特征

Genomic characterization of Tomato yellow leaf curl China virus and its associated satellite DNA infecting tobacco in Guangxi

从中国广西靖西的烟草病株上分离到病毒分离物G102和G103,用双生病毒特异性引物均扩增出约500bp的片段,两者序列同源性达99%。对G102基因组DNA-A全序列测定表明,其全长为2728个核苷酸,与中国番茄黄化曲叶病毒(TYLCCNV)同源性最高,达96.5%。进一步研究发现,G102和G103都伴随有长为1342个核苷酸的卫星DNA分子(DNAβ),这两个DNAβ分子的全序列与TYLCCNV的DNAβ同源性最高,分别为92.9%和93.4%。这是首次明确广西分离的TYLCCNV也伴随有卫星分子。

The virus isolates G102 and G103 were collected from tobacco showing leaf curl symptoms in Jingxi, Guangxi Province. A 0.5kb fragment was obtained by PCR using primers specific to geminivirus genome. The nucleotide sequence identity of the partial DNA-A sequence between the two isolates was over 99%. The complete DNA-A sequence of G102 was determined to be 2728 nucleotides. Comparisons showed that the DNA-A of G102 had the highest sequence identity （96.5%） with that of Tomato yellow leaf curl China virus （TYLCCNV）. Further studies showed that both G102 and G103 were associated with satellite DNA molecules （DNAβ）. Sequence analysis revealed that DNAβ of G102 and G103 contained ]342nt and they shared the highest sequence identities （92.9% and 93.4%, respectively） with that of TYLCCNV. This is the first report that TYLCCNV isolates in Guangxi were also associated with satellite DNA molecules. The previously results demonstrated that all 25 TYLCCNV isolates collected in Yunnan province were associated with DNAβ molecules. The finding that TYLCCNV isolates collected in Guangxi province were also associated with DNAβ molecules gives further evidence that TYLCCNV isolates are associated with DNA β molecules in nature.