Recombination as a motor of host switches and virus emergence: geminiviruses as case studies

• Recombination is inherent to the geminivirus replication process.
• Recombination is adaptive in the family, allowing for host shifts and increased host ranges.
• Recombination within populations facilitates the exploration of sequence space.
• Patterns of recombination reflect population structure and emergence pathways.

Genetic recombination facilitates the transfer of genetic information in a parasexual reproduction manner even between distantly related species. Within the Geminiviridae family, a group of plant-infecting viruses that severely constrain cropping systems worldwide, it is highly suspected that recombination was pivotal in the emergence as a devastating phytopathological problem. Whereas extensive evidence of recombination suggests that this mechanism might be adaptive in this family, direct demonstration remains scarce. Here we assemble lines of evidences indicating that recombination was crucial in driving host switches and further emergence of geminiviruses, making these viruses such successful plant pathogens.