广西番茄烟粉虱传双生病毒的分布及遗传多样性分析

目的]调查研究侵染广西番茄的双生病毒种类、分布及复合侵染情况,为广西番茄育种及抗病品种布局提供理论依据.方法]自2011年起,对引起广西番茄曲叶病的双生病毒进行调查、鉴定,并采集疑似双生病毒侵染的番茄样品189份,提取样品总DNA,利用双生病毒简并引物对样品进行检测,挑选部分阳性样品的PCR产物,纯化后连接至克隆载体进行测序,并与GenBank已报道的序列进行比对分析.同时选取不同地区的各病毒分离物进行全序列扩增和测定,构建系统发育进化树,研究其进化关系及遗传多样性.结果]通过PCR检测发现,189份番茄样品中139份为阳性样品,阳性检出率为73.54％.挑选具代表性的番茄样品进行测序比对分析,发现引起广西番茄曲叶病的双生病毒有4种:中国番茄曲叶病毒、中国番木瓜曲叶病毒、中国番茄黄化曲叶病毒和中国胜红蓟黄脉病毒,且样品存在复合侵染现象,存在7种以上不同类型的复合侵染现象;共获得47个各病毒分离物的病毒全长基因组序列.通过系统发育进化树分析发现,各病毒分离物按地域处于不同的分支,表现较丰富的遗传进化关系.结论]侵染广西番茄的双生病毒有4种,广泛分布于广西主要的番茄种植区,且病毒的侵染多为复合侵染.侵染广西番茄的双生病毒具地域分布性.

Distribution and genetic diversity of tomato-infecting begomoviruses in Guangxi,China

Objective]The present study investigated virus species,distributions,and mixed-infections of tomato-infecting begomoviruses in Guangxi,in order to provide theoretical support for tomato breeding and rational distribution of tomato anti-virus variety.Method]Since 2011,the study have investigated and identified begomoviruses which caused tomato yellow leaf curl disease (TYLCD) in Guangxi,and collected 189 samples with typical symptoms of begomoviruses infection.Total DNA were extracted and all the samples were detected using degenerate primers of begomoviruses.PCR products of positive samples were selected,purified and sequenced after linking to clone vector.The sequences were compared to those in GenBank.Virus isolates from different places were selected,full-length amplification and detection of these isolates were conducted.The researchers also established phylogenetic trees to study their evolutionary relationships and genetic diversity.Result]According to PCR detection,there were 139 positive samples out of 189 tomato samples,positive rate being 73.54％.Typical tomato samples were selected and sequenced,four kinds of begomoviruses that caused TYLCD in Guangxi were found:Tomato leaf curl China virus,Papaya leaf curl China virus,Tomato yellow leaf curl China virus and Ageratum yellow vein China virus.Complicated mixed infections were detected in the samples and at least seven types of mixed infections were found.Forty-seven full DNA-A sequences of virus isolates were obtained.Phylogenetic tree analysis indicated that virus isolates from the same region belonged to the same sub-clade,and showed rich genetic evolutionary relationship.Conclusion]After investigation and identification,four kinds of tomato-infecting begomoviruses are found existing in Guangxi.They are widely distributed in major tomato planting regions in Guangxi,and complicated mixed infections occur among them.Certain kinds of tomatoinfecting begomoviruses distribute in certain regions.