Repeatable Population Dynamics among Vesicular Stomatitis Virus Lineages Evolved under High Co-infection

Abstract

Parasites and hosts can experience oscillatory cycles, where the densities of these interacting species dynamically fluctuate through time. Viruses with different replication strategies can also interact to produce cyclical dynamics. Frequent cellular co-infection can select for defective-interfering particles (DIPs): “cheater” viruses with shortened genomes that interfere with intracellular replication of full-length (ordinary) viruses. DIPs are positively selected when rare because they out-replicate ordinary viruses during co-infection, but DIPs are negatively selected when common because ordinary viruses become unavailable for intracellular exploitation via cheating. Here, we tested whether oscillatory dynamics of ordinary viruses were similar across independently evolved populations of vesicular stomatitis virus (VSV). Results showed identical cyclical dynamics across populations in the first 10 experimental passages, which transitioned to repeatable dampened oscillations by passage 20. Genomic analyses revealed parallel molecular substitutions across populations, particularly novel mutations that became dominant by passage 10. Our study showed that oscillatory dynamics and molecular evolution of interacting viruses were highly repeatable in VSV populations passaged under frequent co-infection. Furthermore, our data suggested that frequent co-infection with DIPs caused lowered performance of full-length viruses, by reducing their population densities by orders of magnitude compared to reproduction of ordinary viruses during strictly clonal infections.

Pleiotropy, cooperation, and the social evolution of genetic architecture

“…Furthermore, this is only one way in which social interactions could drive genome evolution. Other possibilities include mutualistic cooperation leading to genome degradation or gene transfers between species and selection for cheating leading to genome reduction, genome compartmentalisation, or the sequestering of cooperative traits onto mobile genetic elements [ 42 , 43 , 73 – 78 ].…”

Effects of historical co‐infection on host shift abilities of exploitative and competitive viruses

“…2013, Williams et al. 2016). Here, we examined whether these differences in selective pressures would affect the ability of viral clones previously evolved at low or high MOI to infect novel host cells, even though median fitness of clones from different treatments was indistinguishable on the typical laboratory host.…”

“…For example, viruses that specialize in sequestering and assembling proteins may take advantage of the proteins encoded by co-infecting genotypes that instead maximize transcription (Turner and Duffy 2008). Cheater viruses may even evolve reduced genome sizes by deleting essential genes, enabling faster replication despite their reliance on fully functional co-infecting genotypes (Huang and Baltimore 1970;Huang 1973, Horiuchi 1983, Williams et al 2016. In contrast, at low MOI virus coinfection is relatively rare, and intracellular competition should be less important as a selective pressure.…”

An overview of process intensification and thermo stabilization for upscaling of Peste des petits ruminants vaccines in view of global control and eradication

“…Population dynamic models of DIP-virus interaction presumes that co-infection of a cell with at least one DIP will prevent that cell from making any standard virus particles and the co-infected cells will produce only DIPs [44,83]. Thus, DIPs will readily evolve in natural virus populations under frequent conditions of co-infection which can lower the fitness of full length viruses within the cell [91].…”