马铃薯Y病毒中国分离物的分子株系组成

 马铃薯Y病毒(potato virus Y,PVY)主要侵染马铃薯和烟草等茄科作物,给世界农业造成巨大经济损失。本文对测定的23个及GenBank中注册的52个中国PVY分离物ORF序列进行了系统发育、重组和选择压等分析。系统发育分析表明,根据ORF序列可把我国75个PVY分离物和国外30个参比分离物分成O、C、E、NTN-NW(SYR-I型)、NTN-NW(SYR-II型)、NTN(NTN-a型)、NTN(NTN-b型)、NA-N/NTN、Eu-N、N-Wi(N:O型)和N-Wi(N-Wi型)等11个分子株系,其中中国PVY分离物属于除E和C株系外的9个分子株系。除ME162、guiyang、PVYzu、SD-G、WA-13和CN:JL-1:17等 6个分离物基因组中未检测到重组,其余69个分离物均存在明显重组。根据重组位点的不同,中国PVY可分为11种重组类型,其中5种为新的重组类型。选择压分析表明,中国PVY分离物的11个基因均处于负选择,其中核内含体b基因受到的选择压最大,PIPO受到的选择压最小。基因流分析表明,黑龙江、河南和山东PVY分离物间基因交流频繁,马铃薯与烟草PVY分离物之间基因交流频繁。本研究的结果明确了中国PVY分离物的分子株系组成,对指导PVY的检测和防控具有积极作用。

Molecular strain composition of potato virus Y isolates from China

Potato virus Y (PVY) mainly infects solanaceous crops including potato and tobacco, and causes huge economic losses to agriculture worldwide. Phylogenetic relationship, sequence recombination, and selection pressure were analyzed using the ORF sequences of 23 PVY isolates determined in this research and those of 52 isolates deposited in the GenBank. The phylogenetic analysis of ORF sequences showed that PVY isolates were divided into 11 strains including O, C, E, NTN-NW (SYR-I), NTN-NW (SYR-II), NTN (NTN-a), NTN (NTN-b), NA-N/NTN, Eu-N, N-Wi (N:O), and N-Wi (N-Wi). The PVY isolates from China were clustered into 9 strains excluding strains E and C. Recombination analysis showed that among the 75 Chinese PVY isolates, 69 were recombinants and only six isolates were non-recombinants. According to the difference in recombination sites, these 69 isolates were divided into 11 types of recombination, among which five were new recombination pattern. The results of selection pressure analysis showed that all the 11 proteins of PVY were under negative selection, with NIb gene under the highest selection pressure and PIPO under the least selection pressure. The analysis of gene flow showed the gene flow was frequent among the PVY isolates from potato and tobacco, and the PVY isolates from Heilongjiang, Henan and Shandong. The results presented here have elucidated the molecular strain composition of PVY isolates from China and will be helpful to the detection and control of PVY in China.