First European leaf-feeding grape phylloxera (Daktulosphaira vitifoliae Fitch) survey in Swiss and German commercial vineyards

Abstract

Recent observations report the worldwide incidence of leaf-feeding grape phylloxera in formerly resistant scions of commercial vineyards. To analyze the genetic structure of leaf-feeding phylloxera, we performed an extensive sampling of leaf-feeding phylloxera populations in seven regions (Bcantons^) in Switzerland and Germany. The use of polymorphic microsatellite markers revealed presence of 203 unique grape phylloxera multilocus genotypes. Genetic structure analyses showed a high genetic similitude of these European samples with phylloxera samples from its native habitat on Vitis riparia (northeastern America). Nevertheless, no genetic structure within the European samples was observed, and neither host, geography nor sampling date factors caused clear effects on phylloxera genetic stratification. Clonality was high in commercial vineyards and leaf-feeding grape phylloxera strains were found to be present in scion leaves and rootstock roots in the same vineyard, potentially indicating migration between both habitats. We found indications of sexual reproduction, as shown by high degrees of genetic variation among collection sites.

Use of DNA Markers for Grape Phylloxera Population and Evolutionary Genetics: From RAPDs to SSRs and Beyond

“…Compared to organisms that undergo frequent sexual recombination, the recurrent parthenogenetic generations of grape phylloxera increase its potential to reach ecological specialization in a host [29]. Sexual reproduction is reported to have generated a certain level of genetic diversity within diverse populations [30,31], but it is not clear if such events occurred in the native habitat (and subsequently were introduced into the new range as new genotypes by the secondary introduction of plant material) or in the introduced ranges [30]. On the other hand, somatic variation is considered the major force in aphid evolution [29], capable of generating novel lineages (clones) that are both genetically and phenotypically stable over time [32].…”

“…In fact, it is the only approach with a growing trend in the last decade (Figure 3). By this means, studies have involved analyzing the genetic structure of grape phylloxera using microsatellites in its natural habitat [18] and in many introduced ranges [17,19,31,39,57,58,59].…”

“…According to the authors, the use of a reduced number of markers can identify a high number of the multilocus genotypes present in a sample, which will considerably reduce operational costs. Accordingly, seven of these markers ( Dvit6 , DVSSR4 , DV4 , DV8 , Phy_III_55 , Phy_III_30 , and Phy_III_36 ) proved to be informative enough for the identification of 203 multilocus genotypes from 335 grape phylloxera individuals collected from southern Germany and Switzerland [31]. Obviously, the rate of identification depends on which markers are combined, so further studies testing this core set of microsatellites in wider samples, considering both the native and the introduced ranges, are needed to select the optimum number (and combination) of primers.…”

Comparative Transcriptome Analysis of Two Root-Feeding Grape Phylloxera (D. vitifoliae) Lineages Feeding on a Rootstock and V. vinifera

“…The majority of rootstocks used in modern viticulture are ranked tolerant against grape phylloxera, thus hosting grape phylloxera populations without host damage [ 20 ]. Reports of grape phylloxera root infestations leading to crop loss and significant vine damage are increasing worldwide [ 26 , 27 , 28 ], partially explained by the evolution and spread of host-adapted grape phylloxera biotypes [ 29 , 30 ]. A classification system for grape phylloxera defines seven biotypes (A-G), based on insect performance (e.g., life table parameters), host plant responses (e.g., gall numbers), and the feeding tissue (leaf versus root) [ 31 ].…”

“…Although the morphological modifications during grape phylloxera root gall formation are comparably well studied [ 8 , 9 , 13 , 16 , 17 , 24 , 35 , 36 , 37 ], the underlying biomolecular basis of root-feeding grape phylloxera biotypes is far from clear. Work employing molecular markers failed to identify biomarkers linked to host preference, e.g., [ 25 , 28 , 38 , 39 ] other than leaf feeding in native habitats.…”