Recombination hotspots and host susceptibility modulate the adaptive value of recombination during maize streak virus evolution

BMC Evolutionary Biology

Research Article

Arvind Varsani¹  Darren P Martin²  Adérito L Monjane³  Edward P Rybicki⁴  Eric van der Walt⁵ 

[1] Biomolecular Interaction Centre, University of Canterbury, Private Bag 4800, 8140, Christchurch, New Zealand;School of Biological Sciences, University of Canterbury, Private Bag 4800, 8140, Christchurch, New Zealand;Electron Microscope Unit, University of Cape Town, Rondebosch, 7701, Cape Town, South Africa;Computational Biology Group, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, 7925, Cape Town, South Africa;Centre for High-Performance Computing, Rosebank, Cape Town, South Africa;Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, 7701, Cape Town, South Africa;Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, 7701, Cape Town, South Africa;Computational Biology Group, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, 7925, Cape Town, South Africa;Kapa Biosystems, P.O. Box 12961, 7705, Mowbray, South Africa;

关键词: Single Polymorphic Nucleotide;    Recombinant Virus;    Fitness Landscape;    Parental Virus;    Maize Genotype;   

DOI  :  10.1186/1471-2148-11-350

 received in 2011-09-15, accepted in 2011-12-02,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundMaize streak virus -strain A (MSV-A; Genus Mastrevirus, Family Geminiviridae), the maize-adapted strain of MSV that causes maize streak disease throughout sub-Saharan Africa, probably arose between 100 and 200 years ago via homologous recombination between two MSV strains adapted to wild grasses. MSV recombination experiments and analyses of natural MSV recombination patterns have revealed that this recombination event entailed the exchange of the movement protein - coat protein gene cassette, bounded by the two genomic regions most prone to recombination in mastrevirus genomes; the first surrounding the virion-strand origin of replication, and the second around the interface between the coat protein gene and the short intergenic region. Therefore, aside from the likely adaptive advantages presented by a modular exchange of this cassette, these specific breakpoints may have been largely predetermined by the underlying mechanisms of mastrevirus recombination. To investigate this hypothesis, we constructed artificial, low-fitness, reciprocal chimaeric MSV genomes using alternating genomic segments from two MSV strains; a grass-adapted MSV-B, and a maize-adapted MSV-A. Between them, each pair of reciprocal chimaeric genomes represented all of the genetic material required to reconstruct - via recombination - the highly maize-adapted MSV-A genotype, MSV-MatA. We then co-infected a selection of differentially MSV-resistant maize genotypes with pairs of reciprocal chimaeras to determine the efficiency with which recombination would give rise to high-fitness progeny genomes resembling MSV-MatA.ResultsRecombinants resembling MSV-MatA invariably arose in all of our experiments. However, the accuracy and efficiency with which the MSV-MatA genotype was recovered across all replicates of each experiment depended on the MSV susceptibility of the maize genotypes used and the precise positions - in relation to known recombination hotspots - of the breakpoints required to re-create MSV-MatA. Although the MSV-sensitive maize genotype gave rise to the greatest variety of recombinants, the measured fitness of each of these recombinants correlated with their similarity to MSV-MatA.ConclusionsThe mechanistic predispositions of different MSV genomic regions to recombination can strongly influence the accessibility of high-fitness MSV recombinants. The frequency with which the fittest recombinant MSV genomes arise also correlates directly with the escalating selection pressures imposed by increasingly MSV-resistant maize hosts.

【 授权许可】

Unknown   
© Monjane et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.