Dichorhaviruses Movement Protein and Nucleoprotein Form a Protein Complex That May Be Required for Virus Spread and Interacts in vivo With Viral Movement-Related Cilevirus Proteins

Author(s)

Leastro, Mikhail Oliveira ^{[1, 2]} ; Freitas-Astua, Juliana ^{[1, 3]} ; Kitajima, Elliot Watanabe ^[4] ; Pallas, Vicente ^[2] ; Sanchez-Navarro, Jesus angel ^[2]

Affiliation

^[1] Inst Biol, Unidade Lab Referencia Biol Mol Aplicada, Sao Paulo - Brazil

^[2] Univ Politecn Valencia, Consejo Super Invest Cient CSIC, Inst Biol Mol & Celular Plantas, Valencia - Spain

^[3] Embrapa Mandioca & Fruticultura, Cruz Des Almas - Brazil

^[4] Univ Sao Paulo, Dept Fitopatol & Nematol, Escola Super Agr Luiz de Queiroz, Piracicaba - Brazil

• Document type: Journal article
• Source: FRONTIERS IN MICROBIOLOGY; v. 11, NOV 4 2020.
• Web of Science Citations: 0

Abstract

Brevipalpus-transmitted viruses (BTVs) belong to the genera Dichorhavirus and Cilevirus and are the main causal agents of the citrus leprosis (CL) disease. In this report, we explored aspects related to the movement mechanism mediated by dichorhaviruses movement proteins (MPs) and the homologous and heterologous interactions among viral proteins related to the movement of citrus leprosis-associated viruses. The membrane-spanning property and topology analysis of the nucleocapsid (N) and MP proteins from two dichorhaviruses revealed that the MPs are proteins tightly associated with the cell membrane, exposing their N- and C-termini to the cytoplasm and the inner part of the nucleus, whereas the N proteins are not membrane-associated. Subcellular localization analysis revealed the presence of dichorhavirus MPs at the cell surface and in the nucleus, while the phosphoproteins (P) were located exclusively in the nucleus and the N proteins in both the cytoplasm and the nucleus. Co-expression analysis with the MP, P, and N proteins showed an interaction network formed between them. We highlight the MP capability to partially redistribute the previously reported N-P core complex, redirecting a portion of the N from the nucleus to the plasmodesmata at the cell periphery, which indicates not only that the MP might guide the intracellular trafficking of the viral infective complex but also that the N protein may be associated with the cell-to-cell movement mechanism of dichorhaviruses. The movement functionality of these MPs was analyzed by using three movement-defective infectious systems. Also, the MP capacity to generate tubular structures on the protoplast surface by ectopic expression was analyzed. Finally, we evaluated the in vivo protein-protein interaction networks between the dichorhavirus MP and/or N proteins with the heterologous cilevirus movement components, which suggest a broad spectrum of interactions, highlighting those among capsid proteins (CP), MPs, and Ns from citrus leprosis-associated viruses. These data may aid in understanding the mixed infection process naturally observed in the field caused by distinct BTVs. (AU)

• FAPESP's process: 17/19898-8 - The involvement of the movement protein (MP) of Citrus leprosis-associated viruses with the natural restraint of systemic viral spread in the plant.
• Grantee: Mikhail Oliveira Leastro
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 15/10249-1 - Studies of infective processes of Citrus leprosis virus (CiLV-C), with emphasis in the construction of infectious clone and characterization of viral proteins.
• Grantee: Mikhail Oliveira Leastro
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/50222-0 - Understanding the molecular biology and ecology of plant-virus-vector relationships: towards sustainable, integrated virus management strategies
• Grantee: Juliana de Freitas Astúa
• Support Opportunities: Regular Research Grants