Contrasting genetic structure between two begomoviruses infecting the same leguminous hosts.

Area of Science:

• Plant Virology
• Molecular Evolution
• Epidemiology

Background:

• Begomoviruses, whitefly-transmitted ssDNA viruses, cause significant crop epidemics globally.
• Wild plants serve as reservoirs and recombination hotspots for begomoviruses, potentially increasing viral genetic diversity.
• Previous studies suggested higher genetic variability in begomoviruses from non-cultivated hosts.

Purpose of the Study:

• To investigate the effect of host type (cultivated vs. non-cultivated) on the genetic variability of begomovirus populations.
• To compare the genetic variation and population structure of Bean golden mosaic virus (BGMV) and Macroptilium yellow spot virus (MaYSV).

Main Methods:

• Sequencing of 212 full-length DNA-A genome segments from begomoviruses infecting common bean, lima bean, and Macroptilium lathyroides in Brazil.
• Analysis of genetic variation and population structure for BGMV and MaYSV populations.
• Identification of recombination events as a factor influencing viral genetic diversity.

Main Results:

• Contrary to expectations, similar genetic variation was observed between begomovirus populations infecting cultivated and non-cultivated hosts.
• MaYSV populations exhibited higher genetic variation than BGMV populations, primarily due to extensive recombination events in MaYSV.
• BGMV populations showed distinct geographical and host-based structuring, while MaYSV populations did not.

Conclusions:

• The host type does not appear to be a primary driver of genetic variability in these begomovirus populations.
• Recombination is a significant factor shaping the genetic diversity of MaYSV.
• BGMV population dynamics are influenced by both host association and geographical factors, unlike MaYSV.