Reconstructing the history of maize streak virus strain a dispersal to reveal diversification hot spots and its origin in Southern Africa
Maize streak virus strain A (MSV-A), the causal agent of maize streak disease, is today one of the most serious biotic threats to African food security. Determining where MSV-A originated and how it spread transcontinentally could yield valuable insights into its historical emergence as a crop pathogen. Similarly, determining where the major extant MSV-A lineages arose could identify geographical hot spots of MSV evolution. Here, we use model-based phylogeographic analyses of 353 fully sequenced MSV-A isolates to reconstruct a plausible history of MSV-A movements over the past 150 years. We show that since the probable emergence of MSV-A in southern Africa around 1863, the virus spread transcontinentally at an average rate of 32.5 km/year (95% highest probability density interval, 15.6 to 51.6 km/year). Using distinctive patterns of nucleotide variation caused by 20 unique intra-MSV-A recombination events, we tentatively classified the MSV-A isolates into 24 easily discernible lineages. Despite many of these lineages displaying distinct geographical distributions, it is apparent that almost all have emerged within the past 4 decades from either southern or east-central Africa. Collectively, our results suggest that regular analysis of MSV-A genomes within these diversification hot spots could be used to monitor the emergence of future MSV-A lineages that could affect maize cultivation in Africa.
Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , |
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Format: | article biblioteca |
Language: | eng |
Subjects: | H20 - Maladies des plantes, virus striure du maïs, plante alimentaire, http://aims.fao.org/aos/agrovoc/c_33375, http://aims.fao.org/aos/agrovoc/c_3017, http://aims.fao.org/aos/agrovoc/c_7252, http://aims.fao.org/aos/agrovoc/c_165, |
Online Access: | http://agritrop.cirad.fr/561377/ http://agritrop.cirad.fr/561377/1/J.%20Virol.-2011-Monjane-9623-36.pdf |
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