Multiple Introductions of the Old World Begomovirus Tomato yellow leaf curl virus into the New World

Abstract

A phylogenetic analysis of three genomic regions revealed that Tomato yellow leaf curl virus (TYLCV) from western North America is distinct from TYLCV isolated in eastern North America and the Caribbean. This analysis supports a second introduction of this Old World begomovirus into the New World, most likely from Asia.

98% identical, 100% wrong: per cent nucleotide identity can lead plant virus epidemiology astray

“…Hainan is an island in the South China Sea and its first BBTV isolates grouped with those of nearby Vietnam (Jun & Zhi-Xin 2005). The more recently sequenced isolate from June 2008 is more closely related to viruses (Duffy & Holmes 2007) or labelled according to convention (Fauquet et al 2008) and given with its GenBank accession number.…”

“…An updated tree created from an alignment of partial coat protein genes, which recapitulates the two geographically distinct New World clades (Duffy & Holmes 2007;Zhang et al 2009), is given in figure 1. The more recently isolated viruses were published with PNI to a range of closely related TYLCV isolates, but our phylogenetic analysis offers better resolution of the ancestry of some of these strains.…”

“…One directly relevant application would be comparing the likelihood of two hypothetical evolutionary histories: one where a virus is allowed to have multiple introductions to a geographical region, and one where all isolates from the geographical region must be descended from a single introduction (e.g. Duffy & Holmes 2007).…”

“…As the western Mexican sequences were 98 per cent identical to those from the eastern Caribbean, the infections in western Mexico were thought to be an extension of the initial introduction . Despite this substantial per cent nucleotide identity (PNI), subsequent phylogenetic analysis revealed that these western Mexican sequences were more closely related (greater than 99%) to TYLCV in Asia than in other North American isolates and represented a second introduction of this exotic virus into North America (Duffy & Holmes 2007).…”

Brazilian Begomovirus Populations Are Highly Recombinant, Rapidly Evolving, and Segregated Based on Geographical Location

“…In the Americas, diseases caused by begomoviruses have significantly impacted tomato production since the 1980s (8)(9)(10). With the exception of Tomato yellow leaf curl virus (TYLCV), which was first introduced to the Americas via tomato seedlings imported into the Dominican Republic from Israel (11) and has now spread to the United States, Mexico, and a number of countries in the Caribbean (12), all begomoviruses isolated and characterized from tomato plants from the American continents (North, Central, and South America) are native to these continents and have never been detected in other regions (for examples, see references 13, 14, and 15). In fact, the phylogeny of geminiviruses as a whole is highly structured around geographical distributions of its composite viruses (2).…”