The Orchestrated Role of Three Multifunctional Luteovirus Proteins in Virus Movement within Plant Hosts and Aphid Vectors
Emerging Pests and Pathogens
2012 Annual Report
1a.Objectives (from AD-416):
This proposal focuses on developing a platform and pipeline to integrate biomarker technology into IPM strategies for the control of multiple hemipteran insect species that transmit circulative plant viruses. The Overall objective is to dissect the molecular and cellular functions of several virus proteins that together regulate the phloem specific movement of virus in host plants and the tissue specific movement of virus in aphid vectors. Specifically we plan to:
1. Identify the active domains of the RTP and its interacting plant proteins that operate to limit the virus to phloem tissues where it is available to aphids.
2. Identify aphid and plant proteins that interact with the CP and RTP, and the mechanisms that allow these complexes to orchestrate the transport of virus across aphid gut and salivary tissues and the survival of virus in the aphid hemolymph.
3. Identify the mechanisms by which the P17 influences the uptake of virus by aphids and influences the transmission efficiency to other plant hosts.
1b.Approach (from AD-416):
We have shown the CP without RTP can assemble virions, but they are movement impaired in both plants and aphids. CP and RTP act together to regulate virus movement and survival in the aphid. RTP also functions as a soluble protein to confine virus to phloem tissues. P17, a nonstructural virus movement protein, acts in a host dependent manner and affects virus uptake during aphid feeding. Recently, we have identified a number of aphid and aphid symbiont proteins that are linked to virus transmission. Also we have identified a number of plant proteins that co-purify with transmissible virus, but are absent from virus that cannot move through the aphid. The logical extension of this work is to identify which of the aphid and plant candidate proteins are truly interacting with which virus protein and to determine how these various proteins orchestrate virus movement in the plant and aphid to ensure maximum transmission and continued virus existence. Our approach will focus on the use of the latest techniques in targeted proteomics and cell biology to identify aphid, symbiont and plant proteins that interact with each of the virus proteins. Mutations in the virus and plant proteins that disrupt these interactions will be used to identify how and where each protein functions independent of, and in concert with, other virus proteins in both plants and aphids. In vitro feeding and microinjection techniques allow us to mix and match various virions and proteins for study in various aphid tissues. GFP tagged proteins will be used to localize interactions to specific tissues and cell organelles.
This research is supported by a NIFA grant that was awarded in April 2012. The SCA with University of Idaho was established in July 2012. Project personnel are being hired. No work has been started on this project.