Emma Hunt

Arthropod Ecophysiology Group

Climate change, arthropod overwintering and pest outbreaks

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Investigating plant-aphid interactions by manipulating aphid diet in planta

Emma Hunt

I did my biology degree at the University of Birmingham. During the 3rd year I undertook a project investigating the development and nutrition of aphid embryos. I spent the four summer holidays during my degree working as part of an international research group at CABI Bioscience in Switzerland. The work involved investigating the use of biological control agents against agricultural insect pests, including the European apple sawfly, Hoplocampa testudinea, Bertha armyworm, Mamestra brassicae and plant bugs, Lygus spp.

I am now carrying out my PhD investigating plant-aphid interactions by manipulating aphid diet in planta (within the plant itself).

Current Research

The nutrition an aphid acquires from the sieve element sap of its host plant is a crucial factor controlling both the initiation and the development of an aphid infestation on crop plants. It is hypothesised that alterations in sieve element (phloem) composition, in particular nitrogen and carbon, will significantly affect an aphid’s initial acceptance or rejection of a plant, as well as its performance, in terms of both the growth rate of individuals and the longer-term reproductive success at the population level (fitness). This in turn suggests potential for the manipulation of selective components of the host plant phloem for the control of aphids.

In this study, I have taken a functional genomics approach aiming to manipulate sieve element nitrogen (amino acid concentration). I have obtained knockout mutants of amino acid transporter genes believed to be located around the phloem in the model plant Arabidopsis thaliana. These include aap6 (amino acid permease, At5g49630) and ant1 (aromatic and neutral amino acid transporter, At5g11900).

Myzus persicae feeding on the model plant Arabidopsis thaliana

Knockout and wildtype plants have been screened for phenotypic changes resulting from the gene knockouts and sieve element sap has also been extracted in order to analyse changes in solute and amino acid composition. The consequent effects on aphid feeding behaviour and performance of the peach-potato aphid, Myzus persicae, on mutant and control plants have also been studied. Aphid performance was assessed as intrinsic rate of increase, rm, and EPG (electrical penetration graph) was used to analyse feeding behaviour.

Clip cage confining an aphid to an Arabidopsis plant. This set up was used in experiments to measure intrinsic rate of increase

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