Cross‐species transferability of microsatellite markers from six aphid (Hemiptera: Aphididae) species and their use for evaluating biotypic diversity in two cereal aphids

Abstract

The abundance and distribution of microsatellites, or simple sequence repeats (SSRs) were explored in the expressed sequence tag (EST) and genomic sequences of the pea aphid, Acyrthosiphon pisum (Harris), and the green peach aphid, Myzus persicae (Sulzer). A total of 108 newly developed, together with 40 published, SSR markers were investigated for their cross-species transferability among six aphid species. Genetic diversity among six greenbug, Schizaphis graminum (Rondani) and two Russian wheat aphid, Diuraphis noxia (Kurdjumov) biotypes was further examined with 67 transferable SSRs. It was found that the pea aphid genome is abundant in SSRs with a unique frequency and distribution of SSR motifs. Cross-species transferability of EST-derived SSRs is dependent on phylogenetic closeness between SSR donor and target species, but is higher than that of genomic SSRs. Neighbor-joining analysis of SSR data revealed host-adapted genetic divergence as well as regional differentiation of greenbug biotypes. The two Russian wheat aphid biotypes are genetically as diverse as the greenbug ones although it was introduced into the USA only 20 years ago. This is the first report of large-scale development of SSR markers in aphids, which are expected to have wide applications in aphid genetic, ecological and evolutionary studies.

Limited Genetic Variation Within and Between Russian Wheat Aphid (Hemiptera: Aphididae) Biotypes in the United States

“…Weng et al (2007) found variation in EST-derived SSRs between Biotypes 1 and 2; however, only a single clone of each biotype was assayed and the biological significance of this variation was not determined. Because D. noxia Biotypes 3, 4, and 5 were indistinguishable from Biotypes 1 and 2, it is likely they a subset of the extant population.…”

Molecular Characterization of Jatropha curcas Resources and Identification of Population-Specific Markers

“…The 10-μl PCR mix consisted of 50 mM MgCl 2 , 1.5 mM dNTPs, 0.25 μM forward primer, 1 μM reverse primer, 1 μM fluorescent dye with M13 tail, 0.45 U Promega Taq, and 10 ng genomic DNA. A single touchdown PCR procedure was set up for all primer amplifications [3,39], and the PCR reactions were performed in the Gene Amp PCR System 9700 (Applied Biosystems, Foster City, CA, USA). The PCR procedure consisted of 3 min at 95°C, followed by six cycles of 45 s at 94°C, 5 min at 68°C (with a 2°C decrease in each cycle), and 1 min at 72°C, followed by eight cycles of 45 s at 94°C, 2 min at 58°C (with a 1°C decrease in each cycle), and 1 min at 72°C, followed by 25 cycles of 45 s at 94°C, 2 min at 50°C, and 1 min at 72°C, followed by a final 7-min extension step at 72°C and stored at 4°C.…”

Molecular Diagnostic for Boll Weevil (Coleoptera: Curculionidae) Based on Amplification of Three Species-Specific Microsatellites

“…There are previous reports of microsatellite primers cross-amplifying DNA from closely related species (Grasela andMcIntosh 2005, Kim and, or even species from a different genus (Wilson et al 2004, Weng et al 2007), but this was not observed for any of the microsatellites in the Anthonomus species tested or the more distantly related pecan weevil (Figs. 3 and 4).…”