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.
Tian
Y P
YP
Department of Plant Pathology, Shandong Agricultural University, Shandong, People's Republic of China.
Liu
J L
JL
Zhang
C L
CL
Liu
Y Y
YY
Wang
B
B
Li
X-D
XD
Guo
Z K
ZK
Valkonen
J P T
JP
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