Functional analysis of the naturally recombinant DNA-A of the bipartite begomovirus Tomato chlorotic mottle virus
Functional analysis of the naturally recombinant DNA-A of the bipartite begomovirus Tomato chlorotic mottle virus
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DOI：
10.1016/j.virusres.2007.02.009
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发表时间：
2007-06-01
期刊：
影响因子：
5
通讯作者：
Fontes, Elizabeth P. B.
中科院分区：
文献类型：
--
作者：
Fontenelle, Mariana R.;Luz, Dirce F.;Fontes, Elizabeth P. B.
在巴西发现的所有双生病毒都属于双生病毒属，具有两部分基因组，分为两个基因组组分DNA-A和DNA-B。然而，二分型菜豆花叶病毒ToCMoV-[MG-Bt]（番茄褪绿斑驳病毒）的DNA-A具有系统感染本塞姆氏烟草的能力作为一个独特的特征。在这里，我们进一步表征这种变体DNA-A，并表明它也感染番茄和其他宿主植物，在DNA-B的情况下。ToCMoV-[MG-Bt]-DNA-A编码一个额外的ORF，命名为AC 5，但其基因组结构与来自西半球菜豆花叶病毒的其他DNA-A相似。我们发现，这个AC 5推定的ORF不是感染所必需的，因为其编码能力的破坏对ToCMoV-[MG-Bt]-DNA-A介导的感染过程没有影响。同样，ToCMoV-[MG-Bt]-DNA-A ac 4突变体在所有测试的宿主中与其野生型对应物不可区分。与此相反，一个av]（外壳蛋白）突变体不能系统感染N。benthamiana和藜藜在DNA-B的情况下。然而，在感染测定中包含DNA-B完全挽救了ToCMoV-[MG-Bt]-DNA-A av/突变体的运动缺陷。这些结果表明，在感染的次优条件下，ToCMoV-[MG-Bt]系统运动需要外壳蛋白。(C)2007 Elsevier B. V.保留所有权利。
All geminiviruses found in Brazil belong to the Begomovirus genus with a bipartite genome that is split between two genomic components, DNA-A and DNA-B. The DNA-A of the bipartite begomovirus ToCMoV-[MG-Bt] (Tomato chlorotic mottle virus), however, possesses as a peculiar characteristic the capacity to systemically infect Nicotiana benthamiana. Here we further characterize this variant DNA-A and show that it also infects Solanum lycopersicum and other host plants, in the absence of DNA-B. The ToCMoV-[MG-Bt]-DNA-A encodes an additional ORF, designated AC5, but otherwise its genome organization is similar to other DNA-A from Western Hemisphere begomoviruses. We showed that this AC5 putative ORF is not essential for infection, as disruption of its coding capacity caused no effect on ToCMoV-[MG-Bt]-DNA-A-mediated infection process. Likewise, the ToCMoV-[MG-Bt]-DNA-A ac4 mutant was indistinguishable from its wild type counterpart in all hosts tested. In contrast, an av] (coat protein) mutant was unable to infect systemically N. benthamiana and Chenopodium quinoa in the absence of DNA-B. However, inclusion of DNA-B in the infection assay fully rescued the movement defect of the ToCMoV-[MG-Bt]-DNA-A av/ mutant. These results suggest that at suboptimal conditions for infection the coat protein is required for ToCMoV-[MG-Bt] systemic movement. (C) 2007 Elsevier B.V. All rights reserved.