斑籽木中番茄黄化曲叶病毒与伴随卫星的分子鉴定及基因组结构分析

Molecular identification and genomic analysis of tomato yellow leaf curl virus and associated betasatellite in Baliospermum solanifolium

中文关键词:茄黄化曲叶病毒  斑籽木  β卫星  重组分析  序列比对  发育树

keywords:tomato yellow leaf curl virus  Baliospermum solanifolium  betasatellite  recombination analysis  sequence alignment  phylogenetic tree

中文摘要:为明确番茄黄化曲叶病毒（tomato yellow leaf curl virus，TYLCV）对杂草斑籽木Baliospermum solanifolium的侵染情况，自云南省元谋县小丙岭村番茄地周边田间地头采集具有黄化、花叶症状的斑籽木病样和健康样品，对样品中病毒及伴随卫星进行PCR检测、全基因组克隆和测序、SDT比对分析、基因组结构特征分析和重组分析。结果显示：从2个斑籽木病样中共分离到4条菜豆金色花叶病毒属Begomovirus病毒DNA-A全序列和4条β卫星全序列；分离的4条DNA-A全基因组序列均与TYLCV中国分离物的核苷酸序列相似性最高，为100.0%；在分离的4条β卫星全序列中，2条β卫星分离物与赛葵黄脉β卫星（Malvastrum yellow vein betasatellite，MaYVB）分离物的核苷酸序列相似性最高，大于99.2%，另外2条β卫星分离物与中国番茄曲叶β卫星（tomato leaf curl China betasatellite，ToLCCNB）分离物的核苷酸序列相似性最高，大于94.6%；系统进化分析结果显示所获得的分离物均与云南省TYLCV分离物亲缘关系较近，获得的所有序列均未发现重组现象。表明TYLCV可伴随不同种的β卫星共同侵染斑籽木，斑籽木是一个易感TYLCV的中间寄主。

Abstract:：In order to assess the incidence of infection by tomato yellow leaf curl virus (TYLCV), symptomatic leaves of the weed with yellowing, mosaic and asymptomotic leaves of Baliospermum solanifolium were collected from the tomato fields in Xiaobingling Village, Yuanmou County, Yunnan Province. The virus and associated satellites in these samples were identified with PCR amplification, sequence cloning, sequence and recombination analysis. Four complete DNA-A and four betasatellite sequences were isolated from two leaf samples with yellowing and mosaic symptoms. Sequence analysis showed that the four DNA-A sequences isolated from YN6210 and YN6212 had the highest nucleotide similarity (with 100.0% nucleotide sequence identity) with the Chinese isolate of tomato yellow leaf curl virus. The complete sequences of the two betasatellites isolated from the YN6210 had the highest nucleotide similarity with Malvastrum yellow vein betasatellite (more than with 99.2% nucleotide sequence identity), and two complete betasatellites sequences isolated from YN6212 had the highest nucleotide similarity with tomato leaf curl China betasatellite (more than with 94.6% nucleotide sequence identity). Phylogenetic analyses showed that these virus or satellite isolates from this study were closely related to those isolates from Yunnan. Recombination analysis showed that no obvious recombination occurred in these sequences from this study. Taken together, this is the first report that B. solanifolium was infected by TYLCV and two species of betasatellites, which also indicates that B. solanifolium is an appropriate intermediate host for TYLCV.