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Department of Plant Sciences


Head of Group: Professor John Carr

john carr

The group investigates how virus infection influences interactions of plants with other organisms and plants’ ability to withstand environmental stresses. We found that viruses can alter the interactions of their plant hosts with insects, such as aphids, that vector viruses. This means that viruses may be able to enhance the rate at which they are spread between plants. We have also found evidence that viruses may ‘pay back’ susceptible hosts by making infected plants more resilient to drought or making the plants more attractive to pollinators. In collaboration with partners in sub-Saharan Africa the group has explored ways of translating our basic research into novel approaches to disrupt insect-mediated virus transmission. 

Carr montageWe work at multiple scales to understand how viruses manipulate plants and the interactions of plants with other organisms. Clockwise: a black bean aphid (Aphis fabae) is tethered by a fine gold wire to allow its feeding behaviour on a virus-infected plant to be electronically monitored (credit: FO Wamonje); a researcher wearing protective equipment releases bees into a walk-in flight arena to determine if these pollinators prefer visiting flowers of healthy or virus-infected plants (credit: AM Murphy and S Jiang); a confocal laser scanning microscope image of the distribution within a plant epidermal cell of a fluorescently tagged viral counter-defence protein (green) (credit: LG Watt), and research group members set up an aphid trap within an experimental field plot in East Africa (credit: FO Wamonje and JP Carr).

Topics of interest include:

  • Do viruses manipulate plant-aphid interactions to facilitate insect-mediated transmission?
  • Does virus infection affect interactions with other organisms in the environment including beneficial ones?

How do signaling pathways mediated by salicylic acid, jasmonic acid and inositol phosphates work together to maintain resistance to pathogens and how are they sometimes subverted by pathogens (in particular viruses)?

Figure 1Understanding how viruses cause disease symptoms

Figure 1. Three tobacco plants infected with cucumber mosaic virus (CMV), a mutant of the virus (CMV∆2b), or treated with a control solution (‘mock’ inoculation). CMV infection causes severe stunting of plants but disease is absent in the plant infected with the mutant virus CMV∆2b. This mutant is unable to express an important CMV factor called the 2b protein, which among other things, is an important determinant of disease symptoms.

Figure 2Probing the behaviour of virus-transmitting insects

Figure 2. An aphid (Myzus persicae) feeds on the surface of an Arabidopsis thaliana leaf. The insect is attached to a fine gold wire to allow its feeding behaviour to be monitored electronically in real time. Studies like this allow us to understand how virus infection alters the feeding behaviour of these insects. This is important because aphids transmit many plant viruses. (Image credit: Dr. Jack Westwood).