Microsatellite and Mitochondrial Data Provide Evidence for a Single Major Introduction for the Neartic Leafhopper Scaphoideus titanus in Europe

Abstract

Scaphoideus titanus, a leafhopper native to North America and invasive in Europe, is the vector of the Flavescence dorée phytoplasma, the causal agent of the most important form of grapevine yellows in European vineyards. We studied 10 polymorphic microsatellite loci and a 623 bp fragment of the mitochondrial cytochrome oxidase II gene in native S. titanus from north-eastern America and introduced European populations, to elucidate the colonization scenario. Consistent with their recent history, invasive European populations were less genetically diverse than American populations for both types of markers, suggesting a recent bottleneck. Significant isolation by distance was detected between American populations but not between European populations. None of the European mitochondrial haplotypes was found in the American vineyards, from which they are assumed to have originated. The precise source of the invasive S. titanus populations therefore remains unclear. Nevertheless, the high heterozygosity of North-East American populations (which contained 92% of the observed alleles) suggests that this region is part of the native range of S. titanus. Clustering population genetics analyses with microsatellite and mitochondrial data suggested that European populations originated from a single introduction event. Most of the introduced populations clustered with populations from Long Island, the Atlantic Coast winegrowing region in which Vitis aestivalis occurs.

Scientific Opinion on pest categorisation of Grapevine Flavescence dorée

“…S. titanus is native to North America and was probably introduced to Europe during the 20th century (Bonfils and Schvester 1960;Schvester et al, 1962;Vidano, 1964). The hypothesis of its recent introduction is supported by the very limited genetic diversity found among the European populations compared with the American ones; this finding also supports the hypothesis of a single introduction of this vector (Bertin et al, 2007;Papura et al, 2009Papura et al, , 2012. The distribution of this species in the EU has been recently reviewed (Chuche and Thiéry, 2014).…”

“…titanus is an efficient vector of FDP (Schvester et al, 1961;Mori et al, 2002). Since its introduction in Europe, probably in south-western France (Papura et al, 2012), S. titanus has expanded its geographical distribution and represents an important risk factor for FDP propagation. Its current distribution ranges from southern Italy to Hungary and from Portugal to Romania.…”

Worldwide invasion routes of the pinewood nematode: What can we infer from population genetics analyses?

“…This makes it difficult to determine which result is the most likely when several alternatives are proposed . However, these classical and Bayesian methods have proved both useful and conclusive in other cases of invasion (Ciosi et al 2008;Facon et al 2003;Kolbe et al 2004;Papura et al 2012;Perdereau et al 2013;Wan et al 2012). We can therefore put forward several hypotheses to account for the conflicting results obtained here: (1) the low level of diversity may have resulted in a lack of power to discriminate between the two possible alternatives, (2) the strong spatial genetic structure observed in the USA, requiring a very large sampling scheme to embrace most genetic variation of the native and (3) the lack of samples from some of the existing invaded areas, such as China or South Korea, potentially serving as sources for the invasion of Europe, as suggested by Figueiredo et al (2013) on the basis of analyses of collection samples for PWN.…”

“…Deciphering geographic pathways followed by invasive species is a key first step in this direction. Many studies carried out over the last decade have tried to identify the invasion routes of several invasive species, including insects (Papura et al 2012;Pascual et al 2007;Perdereau et al 2013;Zepeda-Paulo et al 2010), plants (Kelager et al 2013), nematodes (Boucher et al 2013) and fungi (Fontaine et al 2013). Indeed, this approach can be used to address various questions of both practical and theoretical concern .…”

Contrasting Susceptibilities to Flavescence Dorée in Vitis vinifera, Rootstocks and Wild Vitis Species

“…It can reduce grape harvests significantly and greatly weaken the vineyards development (Pavan et al, 2012). FDp is transmitted by Scaphoideus titanus Ball (Schvester et al, 1963), a leafhopper living and feeding on Vitis that was accidentally introduced into Europe from North America, one century ago (Papura et al, 2012). Recent studies report that FD phytoplasma originated from European wild alders and clematis that surround vineyards (Angelini et al, 2004; Arnaud et al, 2007; Filippin et al, 2009).…”