Submitted to: Annals of the Entomological Society of America
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/6/2010
Publication Date: 2/1/2011
Publication URL: http://handle.nal.usda.gov/10113/58313
Citation: Shufran, K.A., Puterka, G.J. 2011. DNA barcoding to identify all life stages of holocyclic cereal aphids (Hemiptera: Aphididae) on wheat and other poaceae. Annals of the Entomological Society of America. 104(1):39-42. Interpretive Summary: The Russian wheat aphid is an invasive species and has been in the US for more than 20 years. All this time it has reproduced via asexual reproduction, that is, clonally. In 2003 biotypes were found and scientists have been unable to account for their occurrence. A theory is the Russian wheat aphid is now undergoing a sexual reproductive cycle in which genetic recombination occurs. The mixing of genes in the aphid may account for the biotypes. However, the sexual reproductive forms (especially eggs) have not been found. A molecular genetic tool called DNA barcoding was developed that will be applied to help answer this question. Any aphid eggs found on wheat, barley or other grasses will be subjected to DNA barcoding and identified to species. The technique is more effective and accurate than trying to hatch aphid eggs in the laboratory which were found in the field.
Technical Abstract: The cytochrome c oxidase subunit I (COI) gene of the mtDNA was sequenced in eight holocyclic monoecious aphids that occur on wheat, barley, oat, and sorghum in the US. The first 640 bp of the 3' end were considered as a DNA barcoding technique for species identification. DNA barcoding successfully differentiated Schizaphis graminum (Rondani), Diruaphis noxia (Kurdjumov), D. tritici (Gillette), D. frequens (Walker), D. mexicana (McVicar Baker), Sipha flava (Forbes), S. elegans del Guercio, and Sitobion avenae (F.). In addition to the above monoecious species, the common cereal aphids Rhopalosiphum padi (L.) and R. maidis (Fitch) were also included and successfully differentiated. DNA barcoding is a reliable alternative to traditional morphology in the identification of cereal aphids and their various life stages and morphs, including eggs. Its use will be able to confirm whether D. noxia is now reproducing sexually in the US after 20 years of asexual reproduction.