Genetic diversity of Potato virus Y infecting tobacco crops in China.
Genetic variability of Potato virus Y (PVY) isolates infecting potato has been characterized but little is known about genetic diversity of PVY isolates infecting tobacco crops. In this study, PVY isolates were collected from major tobacco-growing areas in China and single-lesion isolates were produced by serial inoculation on Chenopodium amaranticolor. Most isolates (88%) caused systemic veinal necrosis symptoms in tobacco. Of these, 16 isolates contained a PVY(O)-like coat protein (CP) and PVY(N)-like helper component proteinase (HC-pro) and, in this respect, were similar to the PVY(N-Wi), PVY(N:O), and PVY-HN2 isolates characterized from potato in Europe, the United States, and China, respectively; two isolates contained a PVY(O)-like HC-pro and a PVY(N)-like CP; another two isolates had recombination junctions in the CP-encoding region. Both the HC-pro and CP of PVY were under negative selection as a whole; however, seven amino acids in HC-pro and six amino acids in CP were under positive selection. Selection pressures differed between the subpopulations of PVY distinguished by phylogenetic analysis of HC-pro and CP sequences. When PVY isolates from potato were included, no host-specific clustering of the PVY isolates was observed in phylogenetic and nucleotide diversity analyses, suggesting frequent spread of PVY isolates between potato and tobacco crops in the field.
Department of Plant Pathology, Shandong Agricultural University, Shandong, People's Republic of China.
Y P
YP
Tian
J L
JL
Liu
C L
CL
Zhang
Y Y
YY
Liu
B
B
Wang
X-D
XD
Li
Z K
ZK
Guo
J P T
JP
Valkonen
D001483:Base Sequence; D036022:Capsid Proteins / Q000235:genetics*; D002681:China; D003546:Cysteine Endopeptidases / Q000235:genetics*; D014644:Genetic Variation; D016679:Genome, Viral; D010802:Phylogeny; D010935:Plant Diseases / Q000821:virology; D017800:Potyvirus / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D011995:Recombination, Genetic; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA; D012703:Serotyping; D013045:Species Specificity; D014026:Nicotiana / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics*
D036022:Capsid Proteins; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; C072775:HC-Pro protein, potyvirus