title: Reconstructing the history of maize streak virus strain a dispersal to reveal diversification hot spots and its origin in southern Africa.
abstract: 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.
authors.affiliation: Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town, South Africa.
authors.forename: Adérito L
authors.initials: AL
authors.lastname: Monjane
authors.forename: Gordon W
authors.initials: GW
authors.lastname: Harkins
authors.forename: Darren P
authors.initials: DP
authors.lastname: Martin
authors.forename: Philippe
authors.initials: P
authors.lastname: Lemey
authors.forename: Pierre
authors.initials: P
authors.lastname: Lefeuvre
authors.forename: Dionne N
authors.initials: DN
authors.lastname: Shepherd
authors.forename: Sunday
authors.initials: S
authors.lastname: Oluwafemi
authors.forename: Michelo
authors.initials: M
authors.lastname: Simuyandi
authors.forename: Innocent
authors.initials: I
authors.lastname: Zinga
authors.forename: Ephrem K
authors.initials: EK
authors.lastname: Komba
authors.forename: Didier P
authors.initials: DP
authors.lastname: Lakoutene
authors.forename: Noella
authors.initials: N
authors.lastname: Mandakombo
authors.forename: Joseph
authors.initials: J
authors.lastname: Mboukoulida
authors.forename: Silla
authors.initials: S
authors.lastname: Semballa
authors.forename: Appolinaire
authors.initials: A
authors.lastname: Tagne
authors.forename: Fidèle
authors.initials: F
authors.lastname: Tiendrébéogo
authors.forename: Julia B
authors.initials: JB
authors.lastname: Erdmann
authors.forename: Tania
authors.initials: T
authors.lastname: van Antwerpen
authors.forename: Betty E
authors.initials: BE
authors.lastname: Owor
authors.forename: Bradley
authors.initials: B
authors.lastname: Flett
authors.forename: Moses
authors.initials: M
authors.lastname: Ramusi
authors.forename: Oliver P
authors.initials: OP
authors.lastname: Windram
authors.forename: Rizwan
authors.initials: R
authors.lastname: Syed
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Lett
authors.forename: Rob W
authors.initials: RW
authors.lastname: Briddon
authors.forename: Peter G
authors.initials: PG
authors.lastname: Markham
authors.forename: Edward P
authors.initials: EP
authors.lastname: Rybicki
authors.forename: Arvind
authors.initials: A
authors.lastname: Varsani
mesh_terms: D000349:Africa; D016000:Cluster Analysis; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D026762:Maize streak virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D058974:Phylogeography; D010935:Plant Diseases / Q000821:virology*; D017422:Sequence Analysis, DNA; D003313:Zea mays / Q000821:virology*
chemical_list: D004279:DNA, Viral