Affinity purification–mass spectrometry identifies a novel interaction between a polerovirus and a conserved innate immunity aphid protein that regulates transmission efficiency

Authors: Deblasio, Stacy; WILSON, JENNIFER - Cornell University; TAMBORINDEGUY, CECILIA - Cornell University; JOHNSON, RICHARD - University Of Washington; PINHEIRO, PATRICIA - Cornell University; MACCOSS, MICHAEL - University Of Washington; Gray, Stewart; Heck, Michelle

Submitted to: Journal of Proteome Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2021
Publication Date: 5/4/2021
Citation: Deblasio, S.L., Wilson, J., Tamborindeguy, C., Johnson, R., Pinheiro, P., Maccoss, M., Gray, S.M., Heck, M.L. 2021. Affinity purification–mass spectrometry identifies a novel interaction between a polerovirus and a conserved innate immunity aphid protein that regulates transmission efficiency. Journal of Proteome Research. 20(6):3365-3387. https://doi.org/10.1021/acs.jproteome.1c00313.
DOI: https://doi.org/10.1021/acs.jproteome.1c00313

Interpretive Summary: Plant viruses that are spread by aphids, tiny sap-sucking insects, pose a global problem for crop production. During virus spread, aphids land on crops and ingest virus. A subset of plant viruses circulate in the bodies of their aphid vectors. The circulative virus has to move throughout the body of the aphid, passing through aphid cells and tissues during its journey in the aphid body, prior to transmission into a new host plant. During this journey, the virus must interact with aphid proteins. These specific interactions are akin to a lock and key, where the virus interacts with aphid proteins and unlocks entry into the aphid cells. In this work, ARS scientists and University partners used mass spectrometry to identify the aphid proteins that interact with a potato-infecting virus, potato leafroll virus. Understanding these critical virus-aphid protein interactions at the molecular level will yield new strategies to block virus spread into and within a crop.

Technical Abstract: The vast majority of plant viruses are transmitted by insect vectors, and many crucial aspects of the transmission process are mediated by protein-protein interactions. However, to date, very few vector proteins interacting with virus have been identified and functionally characterized. Here we present the first use of a new strategy to identify functionally relevant vector protein complexes interacting with virus: affinity purification coupled to high-resolution mass spectrometry (AP-MS). Using this method, we identified 11 high confidence and 23 medium confidence vector protein interactors of the luteovirid Potato leafroll virus (PLRV) from its primary vector Myzus persicae. Three of our vector-virus protein interactions were confirmed via yeast two-hybrid with PLRV and two other luteovirid species. We further characterized the most enriched interactor, complement component 1 Q subcomponent-binding protein (C1QBP), via localization experiments and chemical inhibition in the insect. We show that MpC1QBP localizes to the mitochondria, endosomes, and the Golgi in plants and C1QBP signal can be observed overlapping with PLRV signal in the cytoplasm and along the periphery of aphid gut epithelial cells. Chemical inhibition of C1QBP in the aphid leads to increased PLRV titer in inoculated plants, supporting the role of C1QBP as a negative regulator of PLRV accumulation in M. persicae. We hypothesize that the innate immune function of C1QBP is conserved in aphids and represents the first instance of aphids mounting an immune response to a non-propagative plant virus.