Recombination, decreased host specificity and increased mobility may have driven the emergence of maize streak virus as an agricultural pathogen

Varsani Arvind, Shepherd Dionne Natalie, Monjane Adérito Luis, Owor Betty E., Erdmann Julia B., Rybicki Edward P., Peterschmitt Michel, Briddon Rob W., Markham Peter G., Oluwafemi Sunday, Windram Oliver P., Lefeuvre Pierre, Lett Jean-Michel, Martin Darren Patrick. 2008. Recombination, decreased host specificity and increased mobility may have driven the emergence of maize streak virus as an agricultural pathogen. Journal of General Virology, 89 (9) : 2063-2074.

Résumé : Maize streak virus (MSV; family Geminiviridae, genus Mastrevirus), the causal agent of maize streak disease, ranks amongst the most serious biological threats to food security in subSaharan Africa. Although five distinct MSV strains have been currently described, only one of these - MSV-A - causes severe disease in maize. Due primarily to their not being an obvious threat to agriculture, very little is known about the ¿grass-adapted¿ MSV strains, MSV-B, -C, -D and -E. Since comparing the genetic diversities, geographical distributions and natural host ranges of MSV-A with the other MSV strains could provide valuable information on the epidemiology, evolution and emergence of MSV-A, we carried out a phylogeographical analysis of MSVs found in uncultivated indigenous African grasses. Amongst the 83 new MSV genomes presented here, we report the discovery of six new MSV strains (MSV-F to -K). The non-random recombination breakpoint distributions detectable with these and other available mastrevirus sequences partially mirror those seen in begomoviruses, implying that the forces shaping these breakpoint patterns have been largely conserved since the earliest geminivirus ancestors. We present evidence that the ancestor of all MSV-A variants was the recombinant progeny of ancestral MSV-B and MSV-G/-F variants. While it remains unknown whether recombination influenced the emergence of MSV-A in maize, our discovery that MSV-A variants may both move between and become established in different regions of Africa with greater ease, and infect more grass species than other MSV strains, goes some way towards explaining why MSV-A is such a successful maize pathogen.

Mots-clés Agrovoc : virus striure du maïs, Zea mays, hôte, variation génétique, recombinaison, génome, pouvoir pathogène, phylogénie, provenance, Maize stripe virus

Mots-clés géographiques Agrovoc : Afrique

Mots-clés complémentaires : Souche (microorganisme)

Classification Agris : H20 - Maladies des plantes

Champ stratégique Cirad : Axe 1 (2005-2013) - Intensification écologique

Auteurs et affiliations

• Varsani Arvind, UCT (ZAF)
• Shepherd Dionne Natalie, UCT (ZAF)
• Monjane Adérito Luis, UCT (ZAF)
• Owor Betty E., UCT (ZAF)
• Erdmann Julia B., UCT (ZAF)
• Rybicki Edward P., UCT (ZAF)
• Peterschmitt Michel, CIRAD-BIOS-UMR BGPI (FRA)
• Briddon Rob W., National Institute for Biotechnology and Genetic Engineering (PAK)
• Markham Peter G., John Innes Centre (GBR)
• Oluwafemi Sunday, Bowen university (NGA)
• Windram Oliver P., University of Warwick (GBR)
• Lefeuvre Pierre, CIRAD-BIOS-UMR PVBMT (REU)
• Lett Jean-Michel, CIRAD-BIOS-UMR PVBMT (REU)
• Martin Darren Patrick, Institute of Infectious Diseases and Molecular Medicine (ZAF)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/545703/)

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