Spread and Changes of Tomato Virus during Plant-to-Plant Transmission

Jim Crocker
2nd November, 2024

Spread and Changes of Tomato Virus during Plant-to-Plant Transmission

This experimental design, involving the serial passaging of Tomato black ring virus (Nepovirus nigranuli) through four distinct scenarios of host plant combinations (S1–S4), revealed that the sequence of host-to-host transmission significantly influences the generation and abundance of defective viral genomes.

Image adapted from: Budzyńska et al. / CC BY (Source)

Key Findings

  • The study by the Institute of Plant Protection in Poland investigated how different host plants affect the formation and dynamics of defective viral genomes (DVGs) in tomato black ring virus (TBRV)
  • Researchers found that DVGs were generated when TBRV was passed through different host species, with the abundance of DVGs varying across plant combinations
  • Deletions were the most common type of DVGs, and their diversity and abundance were influenced by the sequence of host species used in the study
Defective viral genomes (DVGs) are a fascinating aspect of viral biology that emerge due to errors during the replication of viral genomes. These genomes contain significant mutations such as deletions, insertions, genomic rearrangements, and hypermutations. The result is that DVGs cannot complete an infectious cycle without the presence of a helper wild-type virus. This phenomenon has been observed in various viruses, including those infecting humans, animals, and plants. The Institute of Plant Protection-National Research Institute in Poznan, Poland, conducted a study to investigate the impact of host-to-host transmission on DVG formation and population dynamics in vivo using tomato black ring virus (TBRV)[1]. In previous studies, it has been shown that DVGs often accumulate when a virus is serially passaged in the same host at a high multiplicity of infection[2]. These DVGs can interfere with virus replication and play a role in immune responses[3]. The study by the Institute of Plant Protection aimed to understand how different host species affect the generation and dynamics of DVGs during viral evolution. The researchers conducted evolution experiments by sequentially passaging TBRV through four distinct host species: quinoa, tobacco, lettuce, and spinach, changing the host every fifth passage. RNA-Seq data was obtained after 20 passages to analyze the diversity and population dynamics of DVGs. The findings revealed that TBRV DVGs could be generated when the virus was passaged through different host species. The level of DVG abundance varied across the host plant combinations, suggesting that the sequence of host species may influence DVG generation. Interestingly, the study found that deletions were the most prevalent class of DVGs, followed by insertions. The deletion DVG subpopulation exhibited substantial diversity in species composition, and the richness of the deletions was correlated with their abundance. Longer DVGs characterized by small deletions were predominant, while those shorter than 1,000 nucleotides were less common. These findings align with earlier research showing that DVGs can interfere with viral replication and impact virus-host interactions[4]. In the case of TBRV, the study demonstrated that conserved junction sites in the TBRV genome led to the generation of identical deletions in independently evolved viral lineages. This suggests a level of predictability in the formation of DVGs, which could be crucial for understanding viral evolution and devising antiviral strategies. Moreover, the research highlighted the importance of host factors in shaping the selection and evolution of DVGs within a virus population. Previous studies with respiratory syncytial virus (RSV) showed that host permissiveness could drive the accumulation and diversification of DVGs[5]. Similarly, the TBRV study indicates that the interaction between the virus and different host species can significantly influence DVG dynamics. In summary, the research conducted by the Institute of Plant Protection-National Research Institute provides valuable insights into the origin and structure of DVGs in plant viruses. The findings underscore the role of host species in viral evolution and the potential for DVGs to impact virus-host interactions. This study contributes to a broader understanding of viral biology and could inform future strategies for managing viral infections in plants and other organisms.

GeneticsBiochemPlant Science

References

Main Study

1) Population dynamics of defective viral genomes of tomato black ring virus during host-to-host transmission.

Published 31st October, 2024

https://doi.org/10.1128/jvi.01244-24

Related Studies

2) Defective viral genomes are key drivers of the virus-host interaction.

https://doi.org/10.1038/s41564-019-0465-y

3) Identification and quantification of defective virus genomes in high throughput sequencing data using DVG-profiler, a novel post-sequence alignment processing algorithm.

https://doi.org/10.1371/journal.pone.0216944

4) Defective RNA particles derived from Tomato black ring virus genome interfere with the replication of parental virus.

https://doi.org/10.1016/j.virusres.2018.04.010

5) Accumulation of copy-back viral genomes during respiratory syncytial virus infection is preceded by diversification of the copy-back viral genome population followed by selection.

https://doi.org/10.1093/ve/veac091


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