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Carr Group: Plant viruses: Effects on drought resilience


Supervisor: John Carr (Plant Sciences

Project Summary

It seems increasingly likely that in wild plant communities viruses act as mutualists and may influence plant evolution. The 'arms-race' model proposes that evolution of resistance forces more aggressive virus strains to evolve, which in turn drive evolution of better-defended plants and so on, ad infinitum. This may oversimplify plant-virus interactions since 'deal-making' also occurs. For example, many viruses 'pay back' plants by improving drought survival. Hypothetically, resistance becomes a liability if only virus-infected plants survive drought. We will: 1. Use multi-generation 'artificial evolution' experiments to investigate the competitiveness of susceptible versus resistant plants under drought, and 2. Determine how virus-induced drought survival works.

Arabidopsis' rapid 8-week generation time facilitates 'artificial evolution' studies. Turnip mosaic virus enhances drought resilience in infected plants. Depriving plants of water for 14 d (before re-irrigation to allow flowering/seed-set) decreases plant survival to <10%, with survivors yielding 20% of control seed numbers. Starting with 1000 seed (susceptible:resistant in various proportions), selection scenarios will be imposed. Under Scenario 1 (no drought, all plants infected) the 'arms-race' hypothesis should hold with virus-induced decreases in seed yield, causing a 9:1 susceptible:resistant starting population to be 99% resistant in 5 generations (Cf. Control Scenario 2, no virus/no drought: ratios will not change). Under Scenario 3 imposing drought conditions in addition to viral challenge will depress virus-resistant plant seed yield by 80%. If the payback hypothesis is correct, a 9:1 resistant:susceptible population will become >98% susceptible in 6 generations. We will also investigate production of compatible solutes & phytohormones in infected plants to understand the mechanisms of drought resilience. Training: Analytical techniques using liquid chromatography and mass spectroscopy, virology including diagnostics.


  • Carr, J.P. 2017. Exploring how viruses enhance plants' resilience to drought and the limits to this form of viral payback. Plant, Cell and Environment 40: 2906-2908. DOI: 10.1111/pce.13068
  • Groen, S.C., et al. 2016. Virus infection of plants alters pollinator preference: A payback for susceptible hosts? PLoS Pathogens 12(8): e1005790., doi:10.1371/journal.ppat.1005790
  • Roossinck, M.J., & Bazán, E.R. 2017. Symbiosis: Viruses as intimate partners. Annual Review of Virology, 4: 123-139.




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