Identification of new Brome mosaic virus (BMV) isolates systemically infecting Vigna unguiculata L

Katarzyna Trzmiel,Aleksandra Zarzyńska-Nowak,Wiktoria Szydło,Marzena Lewandowska

doi:10.1007/s10658-015-0830-5

Katarzyna Trzmiel, Aleksandra Zarzyńska-Nowak + Show 2 more

Open Access

https://doi.org/10.1007/s10658-015-0830-5

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Abstract

Here we describe two Brome mosaic virus (BMV) isolates from the Wielkopolska region of Poland. The BMV-Sr and BMV-Sz isolates were collected from maize [Zea mays L. ssp. Indentata] and triticale [× Triticosecale Wittm. ex A. Camus] plants respectively. Newly emerged BMV isolates, similarly to the BMV-M2 strain derived from an Arkansas isolate, have a wide host range that includes species in the Poaceae and Fabaceae families. Furthermore, immunological reactions of icosahedral virions from non-inoculated cowpea [Vigna unguiculata L.] leaves with a specific immunoglobulin confirmed that each of these isolates can systemically infect cowpea. We characterized the BMV-Sr and BMV-Sz genomic sequences encoding the replication protein (1a), polymerase (2a), complete movement protein (3a) and coat protein (CP) genes. The 1a, 2a, 3a and CP gene sequences showed 98.9, 97.6, 98.4 and 97.7 % nucleotide sequence identity between the Polish isolates respectively. Phylogenetic analysis based on these four genes confirmed the species identity of the isolates. A phylogenetic tree based on RNA3 (3a and CP genes) showed independent clustering of the Polish isolates. Amino acid sequence analysis of the 3a protein revealed that both Polish isolates are characterized by a single amino acid mutation at the 81st position, when compared with the Russian isolate. It had been previously reported that four amino acid mutations in this region determined BMV systemic infection in cowpea. Our results indicate that a single non-synonymous substitution in the cell-to-cell movement protein may be crucial for the nature of cowpea infection.

Highlights

Brome mosaic virus (BMV), the type member of the Bromovirus genus, has a tripartite genome
Our results indicate that a single non-synonymous substitution in the cell-to-cell movement protein may be crucial for the nature of cowpea infection
The 3a protein encoded by RNA 3 is required for cell-to-cell movement, whereas the subgenomic RNA 4, expressed from the 3′-end of RNA3, encodes the coat protein

Summary

Introduction

Brome mosaic virus (BMV), the type member of the Bromovirus genus, has a tripartite genome. It had been previously reported that four amino acid mutations in this region determined BMV systemic infection in cowpea. Our results indicate that a single non-synonymous substitution in the cell-to-cell movement protein may be crucial for the nature of cowpea infection.

Results

Conclusion