Abstract Viruses of the genus Begomovirus (family Geminiviridae) are a threat to agriculture and food security throughout the warmer parts of the world. Begomoviruses are transmitted by the whitefly Bemisia tabaci and have genomes consisting of one (monopartite) or two (bipartite) circular, single-stranded (ss) DNA molecules. Most monopartite begomoviruses also associate with host range and symptom exacerbating satellites known as betasatellites. Cotton leaf curl Kokhran virus (CLCuKoV), in association with the betasatellite cotton leaf curl Multan betasatellite (CLCuMuB), is one of a number of viruses that cause cotton leaf curl disease in southern Asia. Tomato leaf curl New Delhi virus (ToLCNDV) is a bipartite begomovirus widespread on the Indian subcontinent that has recently also been identified in North Africa and southern Europe and causes problems in a number of crops including cotton and tomato. The Agrobacterium tumefaciens virulence protein VirE2 has ssDNA binding activity. Nicotiana benthamiana was transformed with a construct for the expression of VirE2 to assess its potential to impart resistance to begomoviruses. Plants of three VirE2 transgenic lines showed attenuated symptoms when infected with either CLCuKoV, CLCuKoV with CLCuMuB or ToLCNDV relative to the severe symptoms induced in non-transformed plants. Presence of the betasatellite was found to reduce the effectiveness of the resistance imparted byVirE2. There was a marked reduction in the accumulation of viral/betasatellite DNA for both viruses as detected by Southern hybridization. The results indicate that VirE2 shows promise in efforts to develop non-conventional, broad spectrum resistance against begomoviruses, being active against monopartite and bipartite begomoviruses. Efforts should now focus on investigating VirE2 resistance in crop plants, with a view to developing commercially useful resistant lines.

中文翻译：

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根癌农杆菌单链 DNA 结合蛋白 VirE2 的转基因表达对本氏烟草中的二分和单分 β 卫星相关 Begomoviruses 提供抗性

摘要 Begomovirus 属（双生病毒科）病毒对世界较温暖地区的农业和粮食安全构成威胁。Begomoviruses 由粉虱 Bemisia tabaci 传播，基因组由一个（单部分）或两个（二部分）环状单链 (ss) DNA 分子组成。大多数单部分 begomoviruses 还与宿主范围和症状加剧卫星有关，称为 betasatellites。棉花卷叶科赫兰病毒 (CLCuKoV) 与棉花卷叶木尔坦β卫星 (CLCuMuB) 相关联，是导致南亚棉花卷叶病的多种病毒之一。番茄卷叶新德里病毒 (ToLCNDV) 是一种广泛分布于印度次大陆的二分贝戈莫病毒，最近在北非和南欧也发现了该病毒，并导致包括棉花和番茄在内的许多作物出现问题。根癌农杆菌毒力蛋白 VirE2 具有 ssDNA 结合活性。本氏烟草用表达 VirE2 的构建体转化，以评估其赋予对 begomoviruses 抗性的潜力。相对于在非转化植物中诱导的严重症状，当感染 CLCuKoV、CLCuKoV 和 CLCuMuB 或 ToLCNDV 时，三个 VirE2 转基因品系的植物表现出减弱的症状。发现 β 卫星的存在会降低 VirE2 赋予的抗性的有效性。通过Southern杂交检测到两种病毒的病毒/β卫星DNA的积累显着减少。结果表明，VirE2 在努力开发对 Begomovirus 的非传统、广谱抗性方面显示出前景，对单部分和二部分 begomovirus 具有活性。现在应重点研究作物植物中的 VirE2 抗性，以开发具有商业价值的抗性品系。