Figure 1.
Three CMV strains were inoculated in five Cen-1 Arabidopsis plants each. Each of these 15 plants represented the origin of a lineage of vertically transmitted viruses indicated by blue arrows (left column), another lineage of horizontally transmitted viruses indicated by red arrows (upper row), and a third group of lineages in which vertical and horizontal transmission modes were alternated (diagonal).
Figure 2.
Evolution of CMV seed transmission, virus accumulation and virulence across passages of vertical transmission.
Seed transmission rate (A) was estimated from the number of infected seedlings out of 100 seeds per plant. Virus accumulation (B) was measured as µg of viral RNA per g of fresh leaf tissue. Virulence (C) is represented as one minus the ratio of seed weight in infected to mock-inoculated plants: 1−(SWi/SWm). Data are plotted as mean±standard error of the five independent lineages in each passage for Fny-CMV (blue squares), De72-CMV (red triangles) and LS-CMV (green diamonds). The black line in each panel represents the fitted regression line for lineages of all three strains combined.
Table 1.
Estimates of virus accumulation, virulence and seed transmission rate in vertically infected Cen-1 plants derived from the fifth vertical passage.
Figure 3.
Bivariate analyses between seed transmission, virus accumulation and virulence across passages of vertical transmission.
Significant regressions of seed transmission rate on virus accumulation (A), seed transmission rate on virulence (one minus the ratio of seed weight in infected to mock-inoculated plants, 1−[SWi/SWm]) (B), and virulence on virus accumulation (C), for each virus strain: Fny-CMV (blue squares), De72-CMV (red triangle) and LS-CMV (green diamonds). Note the different scales depending on the trait and the virus strain.
Table 2.
Estimates of virus accumulation, virus effects on vegetative and reproductive growth, virulence, and seed transmission rate in the ‘original’ stock Cen-1 plants for three CMV strains passaged five times by strict vertical, strict horizontal and alternating vertical and horizontal transmission, plus non-evolved strains.
Table 3.
Estimates of virus accumulation, virus effects on vegetative and reproductive growth, and virulence in horizontally inoculated Cen-1 plants derived from the fifth vertical transmission passage.