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

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.

Combining Transient Expression and Cryo-EM to Obtain High-Resolution Structures of Luteovirid Particles

“…The capsids described here answer long-standing questions about the luteovirids. In the past, insights into their architecture have been limited to those from homology modeling, or on biophysical analyses, such as chemical crosslinking and mass spectrometry (Terradot et al, 2001;Kaplan et al, 2007;Chavez et al, 2012;Doumayrou et al, 2016;Alexander et al, 2017). These studies have helped inform biological hypotheses, but are problematic.…”

Defective subviral particles modify ecological equilibria and enhance viral coexistence

“…For example, in our solution S.6.a , we show that due to synergy between virus y and the satellite, x can stably infect the host, while it became extinct in the absence of s . This would be the case of the obligatory mutualism between Pea enation mosaic virus 1 (PEMV1) and Pea enation mosaic virus 2 (PEMV2), where PEMV1 provides a capsid required for PEMV2 transmission while PEMV2 provides a movement protein required for systemic movement of PEMV within the infected plant (Doumayrou et al, 2016).…”

Corn Stunt Disease: An Ideal Insect–Microbial–Plant Pathosystem for Comprehensive Studies of Vector-Borne Plant Diseases of Corn

“…Thus, there is a need to increase our knowledge of the mechanisms used by vectors of plant diseases. In recent years, a surge of studies focusing on hemipteran insect vectors has emerged [ 10 ]. However, most of the plant pathogens being studied are plant viruses transmitted in a non-persistent or semi-persistent manner (e.g., Alfamovirus , Fabavirus , Cucumovirus , Potyvirus , Closterovirus , Sequivirus , and Crinivirus ) [ 11 , 12 , 13 , 14 , 15 , 16 ].…”

“…Similarly, these may be applied to protecting agricultural systems by specifically targeting and disrupting pathogen transmission by rendering vectors refractory to infection or just abolishing pathogen acquisition and/or transmission [ 51 , 52 , 53 , 54 , 55 , 56 ]. To find successful candidates for genetic pest control, much of the recent studies have focused on first achieving a more comprehensive understanding of the complex series of events leading to successful insect vector-phytopathogen-plant interactions [ 10 ]. In our proposed model, the corn stunt pathosystem is expected to contribute to the discovery of key candidate genes that could be useful targets for genetic pest control of an insect vector and plant-infecting spiroplasma threatening corn, a staple crop of worldwide importance.…”