Cervera M T, Riechmann J L, Martín M T, García J A
Centro de Biología Molecular (CSIC-UAM), Centro Nacional de Biotecnología, Madrid, Spain.
J Gen Virol. 1993 Mar;74 ( Pt 3):329-34. doi: 10.1099/0022-1317-74-3-329.
The sequence of the 3'-terminal 1768 nucleotides of the PS and ŏ6 isolates of plum pox virus (PPV) has been determined and compared with that of the equivalent regions of other PPV isolates sequenced previously. The sequenced region is part of the PPV open reading frame encoding the last 186 amino acids of the NIb protein and the coat protein (CP, 330 amino acids), followed by a non-coding region of 220 nucleotides and a poly(A) tail. PPV-PS and PPV(-)ŏ6, just like PPV-El Amar, show rather high levels of nucleotide diversity in the sequence encoding the C-terminal region of the NIb protein (19.4 to 31%) and the N terminus of CP (22.8 to 41.1%) when compared with PPV-Rankovic, PPV-D and PPV-NAT, whereas the level of diversity in the rest of the CP sequence and the 3' non-coding region is low (8 to 10.8% and 5.5 to 7.7%, respectively). However, the first 429 sequenced nucleotides of PPV(-)ŏ6 are very similar to those of the PPV-Rankovic, PPV-D and PPV-NAT isolates, whereas the rest of the sequence clearly resembles PPV-PS. Thus, PPV(-)ŏ6 seems to be the result of a natural recombination event between two wild strains of PPV. To our knowledge this is the first evidence of homologous RNA recombination (a process which could play an important role in the evolution of RNA viruses) within the potyvirus group.
已测定李痘病毒（PPV）的PS和ŏ6分离株3'末端1768个核苷酸的序列，并与先前测序的其他PPV分离株的等效区域进行了比较。测序区域是PPV开放阅读框的一部分，该开放阅读框编码NIb蛋白的最后186个氨基酸和外壳蛋白（CP，330个氨基酸），随后是一个220个核苷酸的非编码区和一个聚腺苷酸尾巴。与PPV-Rankovic、PPV-D和PPV-NAT相比，PPV-PS和PPV(-)ŏ6，就像PPV-El Amar一样，在编码NIb蛋白C末端区域（19.4%至31%）和CP N末端（22.8%至41.1%）的序列中显示出相当高的核苷酸多样性，而CP序列其余部分和3'非编码区的多样性水平较低（分别为8%至1?8%和5.5%至7.7%）。然而，PPV(-)ŏ6的前429个测序核苷酸与PPV-Rankovic、PPV-D和PPV-NAT分离株的非常相似，而序列的其余部分明显类似于PPV-PS。因此，PPV(-)ŏ6似乎是PPV两个野生株之间自然重组事件的结果。据我们所知，这是马铃薯Y病毒组内同源RNA重组（这一过程可能在RNA病毒的进化中起重要作用）的首个证据。
