New insights into phylogenetic diversity of maize yellow mosaic virus revealed by viral sequences from Togo.

Maize yellow mosaic virus (MaYMV) (Polerovirus MAYMV, Solemoviridae) is an emerging virus with a global distribution in maize and other cereals. Transmitted by aphids in a circulative, non-propagative manner, MaYMV forms icosahedral particles and possesses a positive-sense, single-stranded RNA genome. Three distinct phylogenetic groups of MaYMV have been described in Asia, East Africa and America. In this study, 19 genomes from Togo and Burkina Faso were sequenced using Virion-Associated Nucleic Acid-Based Metagenomics (VANA) combined with classical RT-PCR to constitute the first dataset of West African MaYMV genomic sequences. Phylogenetic analyses of global dataset of 92 genomic sequences revealed two sub-lineages within the African strain. We also identified 11 recombinant MaYMV genomes involving intra- and inter-continental exchanges. A comparative analysis of non-recombinant sequences was conducted and identified 19 molecular signatures in proteins P0, P1, P4 and P5. Notably, residue K/R 253 in P5 was lineage-specific and is located near conserved polero- and luteovirus residues known to be involved in aphid interactions, suggesting a potential role in viral transmission.