Widespread Occurrence and Low Genetic Diversity of Colombian datura virus in Brugmansia Suggest an Anthropogenic Role in Virus Selection and Spread

Abstract

Brugmansia (Brugmansia spp.) is a perennial shrub in the Solanaceae, originating from South America, that is a popular landscape plant in the tropics and subtropics and container plant in temperate regions. Virus-like symptoms including mosaic, rugosity, and faint chlorotic spots were first observed on leaves of Brugmansia plants in a south Florida nursery in November 2003. Colombian datura virus (CDV) was identified in these initial plants and subsequent Brugmansia and Datura metel (a Brugmansia relative also grown as an ornamental) plants obtained from Florida, Connecticut, Wisconsin, and California. Overall, 77.5% of Brugmansia and two of four D. metel plants tested were infected with CDV. Partial NIb/CP sequences of 28 Brugmansia CDV isolates from this study were compared with all 16 CDV isolates in GenBank and found to share high levels of nucleotide and amino acid identity, with negative selection estimated to be occurring. A single Brugmansia plant was also infected with a recently described tobamovirus. The low genetic diversity of CDV observed, along with negative selection pressure on NIb/CP, suggests a recent ancestry (<400 years) of the worldwide population of CDV, coinciding with anthropogenic collection and dissemination of Brugmansia plants from their center of origin.