Control of Turnip yellows virus: Assessing impact on oilseed rape quality traits and dissecting circulative transmission by aphids

Coleman, Alexander (2013) Control of Turnip yellows virus: Assessing impact on oilseed rape quality traits and dissecting circulative transmission by aphids. Doctoral thesis, University of East Anglia.

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Turnip yellows virus (TuYV) is one of the most significant viral diseases of
oilseed rape and may be one of main reasons why commercial oilseed rape crops do not
reach their genetic potential. TuYV is transmitted by aphids, sap-sucking hemipteroid
insects, and the green peach aphid (GPA) is the predominant vector. TuYV can reduce
oilseed rape yield by up to 26% in the UK and may also affect oil quality. Current
control measures rely on insecticides; however, changing legislation and reduced
effectiveness necessitate novel approaches to virus control. In this thesis, the impact of
TuYV on the UK commercial oilseed rape crop was established and sources of partial
resistance to TuYV and aphids were investigated. TuYV reduces yield and has a subtle
impact on seed physiology including small changes to fatty acid profiles and
glucosinolate content. Furthermore, these changes appear to be genotype-dependent and
not as a result of virus accumulation in the plant. To learn more about TuYV
transmission by aphids, a novel, functional-genomics tool was developed to silence
aphid genes by plant-mediated RNA interference (PMRi). Highly specific protein
interactions between virus particles and aphid proteins are critical determinants of
circulative transmission, a process whereby virus particles can move between aphid cell
layers. However, the aphid components underlying these processes are poorly
understood. As the GPA Rack1 protein has been implicated in transcytosis of TuYV
particles across the aphid gut barrier, PMRi was used to dissect its role in the circulative
transmission process. This revealed that Rack1 may have a direct role in TuYV
acquisition by GPA. This work further demonstrates the potential of PMRi as a postgenomics
tool in aphids and similar insects, but also as a direct means of aphid and/or
virus control. These contrasting research strategies have provided a two-pronged
approach towards improving TuYV control.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Users 2259 not found.
Date Deposited: 06 Mar 2014 13:13
Last Modified: 06 Mar 2014 13:13


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