Stenger D C, Davis K R, Bisaro D M
Department of Biological Sciences, Northern Illinois University, DeKalb 60115.
Virology. 1994 May 1;200(2):677-85. doi: 10.1006/viro.1994.1231.
Recombinant genomes derived from the Logan and CFH strains of the geminivirus beet curly top virus (BCTV) have been constructed and analyzed for pathogenicity on Nicotiana benthamiana and sugar beet (Beta vulgaris L.). Infectivity assays indicated that the latent period on N. benthamiana was primarily determined by a DNA fragment bearing the leftward open reading frames (ORFs) L1, L2, L3, and L4. Recombinants bearing leftward ORFs from the CFH strain were characterized as having a short latent period (mean = 6-11 days), while the reciprocal recombinants bearing leftward ORFs from the Logan strain had latent periods defined as long (mean = 16-22 days). Infectivity assays on sugar beet indicated that certain recombinant BCTV genomes exhibited novel pathogenic properties not common to either wild type strain, including the loss of systemic movement and replication competency, or asymptomatic systemic infection of sugar beet. The results indicate that N. benthamiana is a more permissive host than sugar beet with respect to heterologous combinations of BCTV genes, and that pathogenicity and virulence of BCTV in sugar beet requires the interaction of certain viral gene products and/or cis-elements that have coevolved in the same strain.
已构建了源自双生病毒甜菜曲顶病毒（BCTV）洛根株系和CFH株系的重组基因组，并对其在本氏烟草和甜菜（Beta vulgaris L.）上的致病性进行了分析。感染性测定表明，本氏烟草上的潜伏期主要由携带向左开放阅读框（ORF）L1、L2、L3和L4的DNA片段决定。携带CFH株系向左ORF的重组体的特征是潜伏期短（平均 = 6 - 11天），而携带洛根株系向左ORF的反向重组体的潜伏期则被定义为长（平均 = 16 - 22天）。对甜菜的感染性测定表明，某些重组BCTV基因组表现出野生型株系均不常见的新致病性，包括系统移动和复制能力丧失，或甜菜的无症状系统感染。结果表明，就BCTV基因的异源组合而言，本氏烟草是比甜菜更易感染的宿主，并且BCTV在甜菜中的致病性和毒力需要同一株系中共同进化的某些病毒基因产物和/或顺式元件的相互作用。
