Genetic Differentiation between Resistance Phenotypes in the Phytophagous Flea Beetle,<i>Phyllotreta nemorum</i>

Jong, Peter W. de; Breuker, Casper J.; Vos, Helene de; Vermeer, K.M.C.A.; Oku, Keiko; Verbaarschot, Patrick; Nielsen, Jens Kvist; Brakefield, Paul M.

doi:10.1673/031.009.6901

Cited by 12 publications

(16 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, many phytophagous insect races also differ in their host discrimination behaviors, which, if mating occurs on or near different hosts, can translate into assortative mating and prezygotic isolation (Funk 1998;Craig et al 2001;Linn et al 2003;Matsubayashi et al 2011). Divergent host performance characters may also isolate demes, wherein feeding or development on a nonnatal host plant results in a reduction in fitness (Via 1991;Brazner and Etges 1993;de Jong et al 2007). Hybrids between insects adapted to different host plants may also be less fit on all hosts than either parental race, a form of extrinsic postzygotic barrier (Dambroski et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Genetically differentiated races and speciation-with-gene-flow in the sunflower maggot, Strauzia longipennis

et al. 2012

View full text Add to dashboard Cite

The ecological interactions parasitic insects have with their hosts may contribute to their prodigious diversity, which is unrivaled among animals. Many insects assumed to be polyphagous generalists have been shown to consist of several differentiated races, each occupying a different host-niche. The sunflower maggot fly, Strauzia longipennis, has long been thought to consist of two or more races due to its substantial intraspecific morphological variation. Here, we use nuclear and mitochondrial markers to test the hypothesis that S. longipennis is a complex of two or more partially reproductively isolated races. We collected S. longipennis flies as pupae from roots of Jerusalem artichoke (Helianthus tuberosus) and as adults swept from leaves of mature H. tuberosus across the breadth of a field season. Flies were scored for morphological variety (typica or vittigera), mitochondrial haplotype (A or B) and a panel of 176 AFLP loci. Bayesian clustering and neighbor-joining phylogenetic analyses of AFLP data supported the existence of at least three, possibly four, genetic races of Strauzia (clusters I, II, III, and V), as well as a small number of putative interracial hybrids (cluster IV). Clusters I and III each consisted of flies of both morphological varieties and both haplotype groups, while flies in cluster II were all of variety typica and all but one was of mitochondrial haplotype B. Flies in cluster II were also collected only as adults on H. tuberosus and not among flies reared from pupae collected from H. tuberosus roots, suggesting that they use a different plant as their larval host. Mean capture date was significantly different between flies of each genetic race, indicating that partial allochronic isolation may be one contemporary barrier to gene flow between races. Evidence that mitochondrial genomes and morphological traits have moved between lineages implies a model of speciation-with-gene-flow for S. longipennis races.

show abstract

Section: Discussionmentioning

confidence: 99%

Genetically differentiated races and speciation-with-gene-flow in the sunflower maggot, Strauzia longipennis

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Although the G-type of Barbarea is resistant to most flea beetle genotypes, it is a major host plant for the species in some localities (Nielsen and de Jong 2005;de Jong et al 2009). Local flea beetle populations that live on the G-type of Barbarea have high frequencies of particular resistance genes (named R-genes), whereas frequencies of these genes in populations that live on other host plants are lower (Nielsen and de Jong 2005).…”

Section: Introductionmentioning

confidence: 99%

Resistance in the Plant, Barbarea vulgaris, and Counter-Adaptations in Flea Beetles Mediated by Saponins

et al. 2010

View full text Add to dashboard Cite

Three saponins and two sapogenins had differential effects on food consumption in five near-isogenic flea beetle lines, which differ in their ability to utilize a novel host plant, Barbarea vulgaris (Brassicaceae). The ability to live on this plant is controlled by major, dominant R-genes in the flea beetle, Phyllotreta nemorum (Coleoptera: Chrysomelidae: Alticinae). A susceptible genotype (rr) is unable to live on the plant, whereas resistant genotypes (RR and Rr) can utilize the novel host plant. Among compounds isolated from B. vulgaris, hederagenin cellobioside (hederagenin-3-O-(4-O-beta-D-glucopyranosyl)-beta-D-glucopyranoside) inhibited feeding, whereas the effect of oleanolic acid cellobioside was much weaker. The aglycones (sapogenins) were inactive. Although hederagenin cellobioside was active against all flea beetle lines, its effect on food consumption was much stronger on the susceptible genotype (rr) compared to the resistant genotype (Rr). Susceptible and resistant flea beetle genotypes were equally sensitive to a non-host saponin, alpha-hederin (hederagenin-3-O-(2-O-alpha-L-rhamnopyranosyl)-alpha-L-arabinopyranoside). These results suggest that R-alleles in flea beetles might be specific adaptations to defensive saponins in B. vulgaris. A possible mechanism of action of the R-alleles might be to encode for an enzyme (e.g. a glucosidase), which is able to cleave glycosidic bonds in hederagenin cellobioside, but not in alpha-hederin. The potential role of saponins as defensive compounds in B. vulgaris and as targets for counter-adaptations in flea beetles and other insects is discussed.

show abstract

“…Evolution of macro-evolutionary divergence in plant-herbivore interactions has therefore in many cases probably been embedded within an allopatric divergence (Thompson 2005;Nyman et al 2010), and it may be difficult to disentangle these two processes (Rundell and Price 2009). The alternative, that divergence evolved in sympatry, has been suggested for herbivores adapting to specific host plants (Edmunds and Alstad 1978;Feder and Filchak 1999;Dres and Mallet 2002;De Jong et al 2009), but is much less likely in plants due to their requirement for external pollination agents for reproduction.…”

Section: Introductionmentioning

confidence: 99%

Genetic and geographic structure of an insect resistant and a susceptible type of Barbarea vulgaris in western Europe

2011

View full text Add to dashboard Cite

Interactions between herbivores and plants are believed to have been important drivers of biodiversity. However, to drive an initial resistance divergence into different evolutionary lineages and taxa, these interactions have probably been embedded in other processes of divergence, like allopatric isolation. The cruciferous plant Barbarea vulgaris ssp. arcuata occurs in Denmark in two types: one (G) is resistant to most genotypes of the flea beetle Phyllotreta nemorum, the other (P) is susceptible. The two types additionally differ in hairiness and glucosinolates, they are genetically strongly divergent, and reproduction between them is reduced. To determine whether the two plant types and their resistance polymorphisms are also present outside Denmark, and to understand how they have evolved, we analysed 33 European populations of B. vulgaris for resistance, hairiness, glucosinolates, and microsatellite markers. Most populations had traits indicative of the G type, including the already characterized Danish G populations. In contrast, only two populations outside Denmark were of the P type; one from northern Sweden and one from Estonia. Genetically, the G populations formed two genetic clusters that were strongly divergent from a genetic cluster containing P populations. A fourth genetic cluster, which contained only a single population and no Danish plants, belonged morphologically to the subspecies ssp. vulgaris. The divergence found in Denmark between a resistant G and a susceptible P type is thus part of a larger divergence in Europe. Judging from the trait correlations, genetic divergence, and partial reproductive incompatibility, the plant types must have been isolated from each other for quite some time. The two P populations outside Denmark came from the north and east, suggesting a more eastern distribution. If so, resistant and susceptible types could have diverged during the ice age and later met in Scandinavia. However, more samples from Eastern Europe are needed to clarify this.

show abstract

Genetic Differentiation between Resistance Phenotypes in the Phytophagous Flea Beetle,Phyllotreta nemorum

Cited by 12 publications

References 36 publications

Genetically differentiated races and speciation-with-gene-flow in the sunflower maggot, Strauzia longipennis

Genetically differentiated races and speciation-with-gene-flow in the sunflower maggot, Strauzia longipennis

Resistance in the Plant, Barbarea vulgaris, and Counter-Adaptations in Flea Beetles Mediated by Saponins

Genetic and geographic structure of an insect resistant and a susceptible type of Barbarea vulgaris in western Europe

Contact Info

Product

Resources

About