Role of Pea Enation Mosaic Virus Coat Protein in the Host Plant and Aphid Vector.

Juliette Doumayrou,W Miller,Bryony Bonning,Melissa Sheber

doi:10.3390/v8110312

Abstract

Understanding the molecular mechanisms involved in plant virus–vector interactions is essential for the development of effective control measures for aphid-vectored epidemic plant diseases. The coat proteins (CP) are the main component of the viral capsids, and they are implicated in practically every stage of the viral infection cycle. Pea enation mosaic virus 1 (PEMV1, Enamovirus, Luteoviridae) and Pea enation mosaic virus 2 (PEMV2, Umbravirus, Tombusviridae) are two RNA viruses in an obligate symbiosis causing the pea enation mosaic disease. Sixteen mutant viruses were generated with mutations in different domains of the CP to evaluate the role of specific amino acids in viral replication, virion assembly, long-distance movement in Pisum sativum, and aphid transmission. Twelve mutant viruses were unable to assemble but were able to replicate in inoculated leaves, move long-distance, and express the CP in newly infected leaves. Four mutant viruses produced virions, but three were not transmissible by the pea aphid, Acyrthosiphon pisum. Three-dimensional modeling of the PEMV CP, combined with biological assays for virion assembly and aphid transmission, allowed for a model of the assembly of PEMV coat protein subunits.

Highlights

As obligate parasites of sessile organisms, the transmission of plant viruses from one host to another is a vital step in their life cycle
The goal of this study is to predict the 3D structure of the coat protein (CP) of Pea enation mosaic virus 1 (PEMV1), and to identify certain aa probably exposed on the surface of the virions that are implicated in viral assembly, replication, and long-distance movement in the pea plant as well as in transmission by aphids
To localize specific sites of the Pea mosaic enation mosaic virus (PEMV) CP potentially involved in vector-borne transmission, the structure was predicted for the coat protein sequence of PEMV1 accession no

Summary

Introduction

As obligate parasites of sessile organisms, the transmission of plant viruses from one host to another is a vital step in their life cycle. While around 80% of plant viruses depend on insect vectors for transmission, more than 70% of all known insect-borne viruses are transmissible by hemipterans [1]. Plant viruses have various transmission strategies involving very specific interactions with their insect vector (i.e., circulative and non-circulative modes [2]). Elucidation of the molecular mechanisms involved in these specialized interactions allows for new approaches to the control of virus diseases that cause extensive agricultural damage. The coat proteins (CPs) are the primary components of the plant virus virion and are implicated in practically every stage of the viral infection cycle [3]. The assembly of the CP to form virions is essential for vector-borne transmission

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