Sung Y K, Coutts R H
Biology Department, Imperial College of Science, Technology and Medicine, London, UK.
J Gen Virol. 1995 Nov;76 ( Pt 11):2809-15. doi: 10.1099/0022-1317-76-11-2809.
Pseudorecombinants made by exchanging the cloned, infectious genome components (DNAs A and B) of potato yellow mosaic geminivirus (PYMV) and the common strain (cs) of tomato golden mosaic geminivirus (csTGMV) are not infectious in their common host Nicotiana benthamiana. In an N. benthamiana leaf disc assay neither PYMV DNA A nor TGMV DNA A transreplicated each other's DNA B component. The ability of PYMV and TGMV to mediate the systemic movement of each other's DNA A was investigated following coinoculation of N. benthamiana with both genome components of one virus (the helper virus) and DNA A of the other virus (the dependent virus). Movement of the dependent virus DNA A in both cases illustrates interchangeability between the DNA B-encoded movement proteins of New World geminiviruses which infect solanaceous hosts. We have studied this genetic interchangeability further in separate co-agroinoculation experiments with N. benthamiana plants using TGMV DNA A to complement mutations in PYMV open reading frame (ORF) AC2, which encodes a protein that trans-activates the expression of virion sense promoters, and in PYMV ORF AC3, which specifies a protein that enhances viral DNA replication. TGMV DNA A complemented a PYMV AC2 mutant and restored its infectivity and it also complemented a PYMV AC3 mutant and restored the reduced DNA phenotype.
通过交换马铃薯黄花叶双生病毒（PYMV）和番茄金色花叶双生病毒普通株系（csTGMV）的克隆感染性基因组组分（DNA A和DNA B）构建的假重组体，在它们的共同寄主本氏烟草中没有感染性。在本氏烟草叶盘试验中，PYMV DNA A和TGMV DNA A都不能反式复制彼此的DNA B组分。在用一种病毒的两个基因组组分（辅助病毒）和另一种病毒的DNA A（依赖病毒）共同接种本氏烟草后，研究了PYMV和TGMV介导彼此DNA A系统移动的能力。在这两种情况下，依赖病毒DNA A的移动说明了感染茄科寄主的新大陆双生病毒中由DNA B编码的移动蛋白之间的互换性。我们在本氏烟草植株的单独共农杆菌接种实验中进一步研究了这种遗传互换性，使用TGMV DNA A来互补PYMV开放阅读框（ORF）AC2中的突变，该开放阅读框编码一种反式激活病毒链启动子表达的蛋白，以及互补PYMV ORF AC3中的突变，该开放阅读框编码一种增强病毒DNA复制的蛋白。TGMV DNA A互补了一个PYMV AC2突变体并恢复了其感染性，它还互补了一个PYMV AC3突变体并恢复了降低的DNA表型。
