A naturally occurring recombinant DNA-A of a typical bipartite begomovirus does not require the cognate DNA-B to infect Nicotiana benthamiana systemically
A naturally occurring recombinant DNA-A of a typical bipartite begomovirus does not require the cognate DNA-B to infect Nicotiana benthamiana systemically
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DOI：
10.1099/vir.0.18783-0
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发表时间：
2003-03-01
影响因子：
3.8
通讯作者：
Fontes, EPB
中科院分区：
文献类型：
--
作者：
Galvao, RM;Mariano, AC;Fontes, EPB
在西半球发现的Begomovirus属（Geminiviridae科）的物种通常具有两部分基因组，由两个2.6 kb的DNA基因组组分DNA- a和DNA- b组成。我们已经鉴定并克隆了基因组；提出了一种新的侵染番茄的巴西begomvirus的组成成分，其名称为番茄皱叶黄病毒（TCrLYV），以及番茄绿斑病毒（ToCMV-[MG-Bt1]）的DNA-A变体。序列分析显示，TCrLYV与ToCMV的亲缘关系最为密切，尽管它的差异足以被认为是一个不同的病毒物种。此外，这些密切相关的病毒在番茄植株中诱导可区分的症状。关于ToCMV-[MG-Bt1] DNA-A，有证据表明其起源于重组。它具有一个杂交基因组，其中复制兼容模块（AC1和复制起源）可能是由ToCMV[BA-Sell]提供的，其余序列可能来自番茄褶叶病毒（ToRMV）。尽管ToCMV-[MG-Bt1]与之前的序列高度保守，但其生物学特性存在显著差异。虽然ToCMV-[MG-Bt1] DNA- a不侵染番茄植株，但在同源DNA- b缺失的情况下，ToCMV-[MG-Bt1] DNA- a会系统性侵染本烟，引起斑斑症状，并在顶端叶片中积累病毒DNA。导致ToCMV-[MG-Bt1] DNA-A的模块化重排可能使该病毒具有更强的侵袭性。我们的研究结果进一步支持了种间重组可能在双病毒多样性及其作为重要农业病原体的出现中发挥重要作用的观点。
Species of the genus Begomovirus (family Geminiviridae) found in the western hemisphere typically have a bipartite genome that consists of two 2.6 kb DNA genomic components, DNA-A and DNA-B. We have identified and cloned genomic; components of a new tomato-infecting begomovirus from Brazil, for which the name Tomato crinkle leaf yellows virus (TCrLYV) is proposed, and a DNA-A variant of Tomato chlorotic mottle virus (ToCMV-[MG-Bt1]). Sequence analysis revealed that TCrLYV was most closely related to ToCMV, although it was sufficiently divergent to be considered a distinct virus species. Furthermore, these closely related viruses induce distinguishable symptoms in tomato plants. With respect to ToCMV-[MG-Bt1] DNA-A,, evidence is presented that suggests a recombinant origin. It possesses a hybrid genome on which the replication compatible module (AC1 and replication origin) was probably donated by ToCMV[BA-Sell] and the remaining sequences appear to have originated from Tomato rugose mosaic virus (ToRMV). Despite the high degree of sequence conservation with its predecessors, ToCMV-[MG-Bt1] differs significantly in its biological properties. Although ToCMV-[MG-Bt1] DNA-A did not infect tomato plants, it systemically infected Nicotiana benthamiana, induced symptoms of mottling and accumulated viral DNA in the apical leaves in the absence of a cognate DNA-B. The modular rearrangement that resulted in ToCMV-[MG-Bt1] DNA-A may have provided this virus with a more aggressive nature. Our results further support the notion that interspecies recombination may play a significant role in geminivirus diversity and their emergence as agriculturally important pathogens.