Subviral DNAs associated with geminivirus disease complexes.

Area of Science:

• Plant Virology
• Molecular Biology
• Agricultural Science

Background:

• Ageratum conyzoides is a widespread weed acting as a reservoir for geminivirus diseases.
• Yellow vein disease in Ageratum plants in Singapore involves a complex mix of viral and subviral DNA.

Purpose of the Study:

• To characterize the viral and subviral components causing yellow vein disease in Ageratum conyzoides.
• To investigate the association of DNA beta and DNA 1 with the begomovirus Ageratum yellow vein virus (AYVV).
• To explore the evolutionary implications of recombination in these DNA components.

Main Methods:

• Analysis of viral, subviral, and recombinant DNA components in infected Ageratum plants.
• Identification of Ageratum yellow vein virus (AYVV) and the satellite DNA beta component.
• Investigation of the role of DNA 1 and nanovirus-like components in disease transmission.

Main Results:

• The whitefly-transmitted disease is caused by Ageratum yellow vein virus (AYVV) and DNA beta.
• A subviral DNA 1 component, possibly adapted from a nanovirus, is also present but not essential for disease.
• Frequent recombination occurs between viral and subviral DNA, generating diversity.

Conclusions:

• Complexes of begomoviruses with satellite DNA, like DNA beta, are significant in plant disease.
• Such viral complexes, including those associated with Cotton Leaf Curl Disease (CLCuD), are widespread in the Eastern Hemisphere.
• These findings suggest a substantial impact on agriculture and underscore the evolutionary role of recombination.