Turnip mosaic virus strain:YC5 Raw sequence reads
We have investigated how the speed of host replacement affects the evolution of virulence and genome dynamics of an RNA virus. Specifically, we have examined how sudden vs. gradual transitions from more susceptible to less susceptible Arabidopsis thaliana genotypes influenced turnip mosaic virus virulence and population genetic diversity. Our results show that the evolution of virulence and the complexity of the mutant swarm is linked to both the type of host succession and the genetic basis of the host resistance. Faster changes in virulence are observed after sudden transitions, with an evolutionary trend towards more severe symptoms that appear latter during infection. Gradual transitions resulted in greater population mutational load and higher genetic polymorphism compared to sudden transitions. In contrast, beneficial mutations associated with sudden transitions had stronger fitness effects than those linked to gradual transitions. This research highlights the importance of considering the speed of environmental changes in virus evolution and provide insights into predicting how viruses adapt and evolve in temporally changing environments, with implications for agriculture and public health.