侵染曼陀罗的中国番茄黄化曲叶病毒及其卫星DNAβ全基因组结构特征

Molecular characterization of Tomato yellow leaf curl China virus and its associated satellite DNAβ infecting Datura stramonium L.

从云南大理曼陀罗上采集到病毒分离物YN72,症状表现为叶脉增厚、叶片褪绿、植株矮化。全序列测定表明,YN72DNA-A全长2 739个核苷酸。基因组比较发现,YN72 DNA-A与中国番茄黄化曲叶病毒分离物(TYLCCNV-[Y43])同源性最高(93.4%),与中国番茄黄化曲叶病毒烟草分离物(TYLCCNV-[Y5])的同源性次之(92.9%),而与亚洲地区的其它双生病毒的同源性均在90%以下,表明曼陀罗中的分离物YN72是TYLCCNV的1个分离物。利用W TG s卫星分子DNAβ的特异性引物beta01和beta02,在YN72中PCR扩增到DNAβ分子。序列分析表明,YN72β全长1 335个核苷酸,在其互补链上编码1个有功能的ORF(C1)。YN72β的全序列与TYLCCNV分离物卫星分子Beanβ和Y297β的同源性最高,分别为99.8%和99.3%;与其它所比较的DNAβ的同源性均低于80.6%。系统进化树研究表明,YN72卫星分子DNAβ与其辅助病毒是共同进化的。

Virus isolate YN72 was obtained from Jimsonweed （Datura stramonium L. ） showing vein thickening, leaf curling and stunt symptoms in Dali, Yunnan province. The complete nucleotide sequence of DNA-A was determined, it contained 2 739 nucleotides. Comparisons showed that DNA-A of YN72 had the highest sequence identity （93.4%） with that of Tomato yellow leaf curl China virus （ TYLCCNV ） isolate Y43, and 92.9% with that of TYLCCNV tobacco isolate Y5, while less than 90% identities were found when compared with other begomoviruses isolated in Asian. It was concluded that isolate YN72 infecting Datura strarnonium L. was one of TYLCCNV isolates. Satellite DNA molecule ＇ YN72 β was found to be associated with YN72 using the primers beta01 and beta02. YN72β consisted of 1 335 nucleotides, with a functional ORF （ C1 ） in complementary-sense DNA. It had 99.8% and 99.3% sequence identities with Beanβ and Y297β associated with TYLCCNV, respectively, and lower than 80.6% sequence identities were found with other reported satellite DNA molecules. Relationship dendrograms showed that satellite DNAβ molecules were coevolved with their help begomoviruses.