helicase domain encoded by cucumber mosaic virus rna1 determines systemic infection of cmr1 in pepper解旋酶域由黄瓜花叶病毒编码rna1决定cmr1全身感染的胡椒.pdfVIP

Helicase Domain Encoded by Cucumber mosaic virus RNA1 Determines Systemic Infection of Cmr1 in Pepper 1 2 3 2 1 Won-Hee Kang , Jang-Kyun Seo , Bong Nam Chung , Kook-Hyung Kim , Byoung-Cheorl Kang * 1 Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, Korea, 2 Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea, 3 National Institute of Horticultural and Herbal Science, Rural Development Administration, Suwon, Korea Abstract The Cmr1 gene in peppers confers resistance to Cucumber mosaic virus isolate-P0 (CMV-P0). Cmr1 restricts the systemic spread of CMV strain-Fny (CMV-Fny), whereas this gene cannot block the spread of CMV isolate-P1 (CMV-P1) to the upper leaves, resulting in systemic infection. To identify the virulence determinant of CMV-P1, six reassortant viruses and six chimeric viruses derived from CMV-Fny and CMV-P1 cDNA clones were used. Our results demonstrate that the C-terminus of the helicase domain encoded by CMV-P1 RNA1 determines susceptibility to systemic infection, and that the helicase domain contains six different amino acid substitutions between CMV-Fny and CMV-P1. To identify the key amino acids of the helicase domain determining systemic infection with CMV-P1, we then constructed amino acid substitution mutants. Of the mutants tested, amino acid residues at positions 865, 896, 957, and 980 in the 1a protein sequence of CMV-P1 affected the systemic infection. Virus localization studies with GFP-tagged CMV clones and in situ localization of virus RNA revealed that these four amino acid residues together form the movement