Exploring the Molecular Mechanisms of Aphid and Thrips Perception in Arabidopsis thaliana

Joyce, Joshua (2023) Exploring the Molecular Mechanisms of Aphid and Thrips Perception in Arabidopsis thaliana. Doctoral thesis, University of East Anglia.

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Plants have evolved sophisticated mechanisms to perceive biotic stresses and launch appropriate defence responses that safeguard their health. Aphids and thrips can threaten plant health both as herbivores and as vectors of plant viruses. Despite this, the mechanisms by which plants perceive localised feeding from these insects are not well characterised. Therefore, the work described in this thesis aimed to investigate how plants perceive feeding by aphids and thrips. To achieve this goal, methods were developed to investigate plant responses to localised stimuli by visualising fluorescent reporters expressed in Arabidopsis thaliana. These methods revealed that feeding from the aphid species Myzus persicae induces intracellular Ca2+ concentration ([Ca2+]) increases which are altered in A. thaliana carrying mutations in both GLUTAMATE RECEPTOR-LIKE (GLR) 3.3 and 3.6. Reporter imaging with localised wound and touch stimuli explored how the GLR3.3 and 3.6 Ca2+-permeable channels might function in damage or mechanical stress perception during localised insect feeding. GLR3.3 alone contributed to the wound-induced [Ca2+] elevations whilst neither channel functioned in responses to touch. Further reporter imaging of wound- and touch-induced responses investigated the role of apoplastic pH and glutamate in regulating GLR3.3 and revealed that localised GLR3.3 activation promotes jasmonate-mediated defence gene expression. GLR3.3 also functioned in responses to feeding by a thrips species, Frankliniella occidentalis, as well as by the aphid species M. persicae, Rhopalosiphum padi and Brevicoryne brassicae. The contribution of GLR3.3 to the responses induced by each species appeared to differ, potentially due to differences in insect feeding behaviour or effector activity. A reverse genetics approach evaluated additional candidate genes for their potential to contribute to aphid or thrips perception in A. thaliana. Through characterising GLR3.3 function in responses to localised wounding, touch, aphid feeding and thrips feeding, this thesis significantly advances the understanding of how plants perceive aphids and thrips.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Chris White
Date Deposited: 05 Sep 2023 10:14
Last Modified: 05 Sep 2023 10:14
URI: https://ueaeprints.uea.ac.uk/id/eprint/92989


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