title: Pseudorecombination between Two Distinct Strains of Cucumber mosaic virus Results in Enhancement of Symptom Severity.
abstract: Recently, a Cucumber mosaic virus (CMV) strain, named as CMV-209, was isolated from Glycine soja. In this study, symptom expression of CMV-209 was analyzed in detail in Nicotiana benthamiana by comparing with that of CMV-Fny, which is a representative strain of CMV. Using infectious cDNA clones of CMV strains 209 and Fny, symptom expression of various pseudorecombinants between these two strains were examined in the early and late infection stages. In the early infection stage, the pseudorecombinants containing Fny-RNA2 induced stunting and leaf distortion on the newly emerged leaves whereas the pseudorecombinants containing 209-RNA2 caused no obvious symptoms. In the late infection stage, the pseudorecombinants containing 209-RNA1 and Fny-RNA2 induced severe leaf distortion and stunting, while CMV-209 induced mild symptom and CMV-Fny caused typical mosaic, general stunting, and leaf distortion symptoms, indicating that RNA 2 encodes a symptom determinant(s) of CMV, which is capable of enhancing symptoms. Furthermore, our results support the possibility that natural recombination between compatible viruses can result in emergence of novel viruses causing severe damages in crop fields.
authors.affiliation: Department of Agricultural Biotechnology and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Korea.
authors.forename: Mi Sa Vo
authors.initials: MS
authors.lastname: Phan
authors.affiliation: Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Korea.
authors.forename: Jang-Kyun
authors.initials: JK
authors.lastname: Seo
authors.affiliation: Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Korea.
authors.forename: Hong-Soo
authors.initials: HS
authors.lastname: Choi
authors.affiliation: Department of Applied Biology, Kyungpook National University, Daegu 702-701, Korea.
authors.forename: Su-Heon
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Agricultural Biotechnology and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Korea ; Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea.
authors.forename: Kook-Hyung
authors.initials: KH
authors.lastname: Kim
keywords: Cucumber mosaic virus; pseudorecombination; symptom expression