Geminivirus diversity and community structure

Circular replication-associated protein encoding single stranded (CRESS) DNA viruses have emerged to become one of the largest and most devastating groups of crops-infecting viruses in tropical and subtropical regions of the world. In West Africa, after the recrudescence of disease-like symptoms in the field, surveys revealed that several CRESS DNA virus species were circulating. The realization that viral diseases of plants may be best understood at an ecosystem scale prompted a survey of plant-associated CRESS DNA virus communities. Here, we describe the diversity of CRESS DNA viruses associated with uncultivated and cultivated plants in two localities of Burkina Faso. A total of 30 distinct species of geminivirus and associated satellites were associated with four cultivated species and eleven uncultivated species. Viruses community maps constructed from the observed virus-host associations revealed a strong modularity within the virus community with clear evidence of associations between particular host and virus species. Whereas few co-infections involving viruses belonging to different host-virus modules were observed, evidence was nevertheless detected of recombination between viruses belonging to different modules. This suggests that co-infections between viruses in different modules does at least occasionally occur: possibly as a consequence of seasonal variations in virus-host community structures with the inter-cropping period in particular promoting such inter-module co-infections.