Dissecting the role of plant immunity in plant-aphid interactions

Prince, David (2012) Dissecting the role of plant immunity in plant-aphid interactions. Doctoral thesis, University of East Anglia.

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Abstract

Aphids are economically important phloem-feeding insects that cause loss in plant
productivity worldwide. This occurs through the removal of photoassimilates and the
vectoring of hundreds of plant viruses. Plants possess a complex immune system in order
to defend themselves from a range of pathogens including bacteria and fungi. I aimed to
discover if this immune system was also involved in defence against aphids.
I found that aphids have proteins that trigger plant immune responses. The aphid
Myzus persicae contains several protein elicitors with varying molecular weights. These
proteins are perceived by the plants Nicotiana benthamiana and Arabidopsis thaliana. In
A. thaliana the perception of a 3 to 10 kDa elicitor fraction requires the leucine-rich repeat
receptor-like kinase (LRR-RLK) BAK1, as a mutant in this gene was deficient in immune
responses activated by this elicitor. Plant recognition of the elicitor is unlikely to depend
on a single non-arginine-asparate (non-RD) RLK.
In addition, aphids possess the means to modulate the plant immune response. I
helped to identify three aphid effectors that modulate plant processes. I then investigated
the role of one of these effectors, a M. persicae chemosensory protein (CSP) known as
Mp10, in suppressing the immune responses triggered by the aphid elicitors. Mp10 is
likely to disrupt the function of plant genes near the top of the immune signalling cascade
in N. benthamiana in order to suppress elicitor-triggered immunity. Surprisingly, the
homologs of this CSP in other aphids also show the same ability to suppress plant
immune responses, suggesting an important role for Mp10 in plant-aphid interactions.
This is the first report of a role for elicitor recognition by plants in aphid defence, the use
of plant cell surface receptors to detect insects, and aphids’ attempts to suppress plant
immunity.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Users 2259 not found.
Date Deposited:	16 May 2013 15:25
Last Modified:	16 May 2013 15:25
URI:	https://ueaeprints.uea.ac.uk/id/eprint/42420
DOI:

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