Viral fitness predicts the magnitude and direction of perturbations in the infected host transcriptome

Héctor Cervera; Silvia Ambrós; Guillermo P. Bernet; Guillermo Rodrigo; Santiago F. Elena

We hypothesized that viral fitness results from a particular interaction between virus and host factors, assuming that the outcome of infection of a WT virus in its natural host results from an optimal (from the virus perspective) modulation of the host's gene expression profile. As viral fitness in the host is reduced, interactions are less optimal and, consequently, the gene expression profile of the plant will be more and more different from that resulting from the successful infection with the WT genotype. To test this hypothesis, we infected N. tabacum plants with each one of the seven TEV genotypes described above. Eight days post-inoculation (dpi) symptomatic tissues were collected for all mutants except for the very low fitness mutant AS13, for which tissues were collected 15 dpi because the delay in symptoms appearance and severity (Fig. 2B) .