The Consequences of Plant Anatomy on Viral Co-Infection

Plant viruses are infectious agents that exploit plants to survive, transmitted from host to host primarily by insect vectors. Within plant hosts, viral populations encounter both physical and physiological barriers that may influence their evolution. This work aims to identify opportunities during host infection for viral populations to interact, so that it can be determined where genetic exchange events occur in the future. I investigated the viral population dynamics of tobacco etch virus (TEV, genus Potyvirus) within the plant host Nicotiana benthamiana using both whole plant and microscopic fluorescence imaging. To achieve this, I inserted three distinct bright and fast folding fluorescent markers into the TEV genome. I then initiated viral infection within plants via Agrobacterium-mediated plant transformation and followed the emergence of fluorescence for up to two weeks. I measured infection timing and success by co-infecting both single primary leaves and pairs of primary leaves, either simultaneously or with a time delay. I also analysed TEV infection microscopically within leaves to compare tissue-level dynamics. My results were consistent with the hypothesis that after initial cell-to-cell expansion of primary loci, TEV is rapidly transported from photosynthetically active ‘source’ tissues to the growing ‘sink’ tissues where sucrose is delivered. I discovered that systemic spread through plant vasculature ‘bypasses’ superinfection exclusion (SIE), so that strains inoculated on separate primary leaves can produce populations of intermixed lesions on systemically infected leaves. This mixing phenomenon is dependent upon location and timing of primary infections. At the microscopic scale, I observed SIE throughout both primary and systemically infected leaves, meaning that lesions of different TEV strains had sharp defined borders with low co-infection at the cellular level. This work forms the starting point for future experiments investigating the role of plant anatomy on viral selection and recombination, and will be used to inform mathematical modelling of viral infection dynamics in plants.<p></p>

Author dc:creator

• Hannah Kilford (21065882)

• Molecular Biology
• Plant Virology
• Plant Biology
• Fluorescent Imaging
• Population Dynamics
• Population Genetics

Statement dc:rights

• All rights reserved
• Open Access after 2027-10-07

Identifier

10779/exe.32060298.v1

OAI identifier oai:identifier

oai:figshare.com:article/32060298