Open AccessGenetic Diversity of Potato virus Y Infecting Tobacco Crops in China
Author(s) -
Yanping Tian,
J. L. Liu,
C. L. Zhang,
Y. Y. Liu,
B. Wang,
X.-D. Li,
Zong-Ming Guo,
Jari P. T. Valkonen
Publication year - 2011
Publication title -
phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.264
H-Index - 131
eISSN - 1943-7684
pISSN - 0031-949X
DOI - 10.1094/phyto-02-10-0055
Subject(s) - potato virus y , biology , potyvirus , phylogenetic tree , genetic diversity , virology , chenopodium , potyviridae , inoculation , virus , plant virus , genetics , gene , botany , horticulture , population , demography , sociology , weed
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.