BACKGROUND In Oman tobacco (Nicotiana tabacum; family Solanaceae) is a minor crop, which is produced only for local consumption. In 2015, tobacco plants exhibiting severe downward leaf curling, leaf thickening, vein swelling, yellowing and stunting were identified in fields of tobacco in Suhar Al-Batina region, Oman. These symptoms are suggestive of begomovirus (genus Begomovirus, family Geminiviridae) infection. METHODS Circular DNA molecules were amplified from total DNA extracted from tobacco plants by rolling circle amplification (RCA). Viral genomes were cloned from RCA products by restriction digestion and betasatellites were cloned by PCR amplification from RCA product, using universal primers. The sequences of full-length clones were obtained by Sanger sequencing and primer walking. Constructs for the infectivity of virus and betasatellite were produced and introduced into plants by Agrobacterium-mediated inoculation. RESULTS The full-length sequences of 3 begomovirus and 3 betasatellite clones, isolated from 3 plants, were obtained. Analysis of the full-length sequences determined showed the virus to be a variant of Chilli leaf curl virus (ChiLCV) and the betasatellite to be a variant of Tomato leaf curl betasatellite (ToLCB). Both the virus and the betasatellite isolated from tobacco show the greatest levels of sequence identity to isolates of ChiLCV and ToLCB identified in other hosts in Oman. Additionally clones of ChiLCV and ToLCB were shown, by Agrobacterium-mediated inoculation, to be infectious to 3 Nicotiana species, including N. tabacum. In N. benthamiana the betasatellite was shown to change the upward leaf rolling symptoms to a severe downward leaf curl, as is typical for many monopartite begomoviruses with betasatellites. CONCLUSIONS The leaf curl disease of tobacco in Oman was shown to be caused by ChiLCV and ToLCB. This is the first identification of ChiLCV with ToLCB infecting tobacco. The study shows that, despite the low diversity of begomoviruses and betasatellites in Oman, the extant viruses/betasatellites are able to fill the niches that present themselves.

中文翻译：

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辣椒叶片卷曲病毒和相关的番茄叶片卷曲β卫星感染阿曼烟草的分子和生物学特性。

背景技术在阿曼烟草（Nicotiana tabacum；茄科）中是次要作物，其仅用于当地消费。2015年，在阿曼Suhar Al-Batina地区的烟草田中发现了烟草植株，表现出严重的叶片向下卷曲，叶片增厚，叶脉肿胀，发黄和发育迟缓。这些症状表明是感染了杆状病毒（Begomovirus属，Geminiviridae家族）。方法采用滚圆扩增法（RCA）从烟草植物提取的总DNA中扩增出环状DNA分子。通过限制性消化从RCA产物中克隆病毒基因组，并使用通用引物通过PCR扩增从RCA产物中克隆β卫星。通过Sanger测序和引物步移获得全长克隆的序列。产生了用于病毒和β-卫星的感染性的构建体，并通过农杆菌介导的接种将其引入植物中。结果获得了从3株植物中分离得到的3株begomovirus和3株β卫星克隆的全长序列。对所确定的全长序列的分析表明，该病毒是辣椒叶片卷曲病毒（ChiLCV）的变体，而β卫星是番茄叶片卷曲β卫星（ToLCB）的变体。从烟草中分离出的病毒和β卫星都显示出与阿曼其他宿主中鉴定出的ChiLCV和ToLCB分离株最大的序列同一性。另外，通过农杆菌介导的接种显示，ChiLCV和ToLCB的克隆可感染3个烟草种，包括烟草。客栈。研究表明，β卫星的benthiana能够将向上的叶子滚动症状改变为严重的向下卷曲的叶子，这是许多带有β卫星的单倍体begomoviruss的典型现象。结论表明阿曼烟草的卷叶病是由ChiLCV和ToLCB引起的。这是ToLCB感染烟草对ChiLCV的首次鉴定。研究表明，尽管在阿曼，初生病毒和β-卫星的多样性较低，但现存的病毒/β-卫星仍能够填补自身的壁ni。