Location: Wheat, Sorghum and Forage ResearchTitle: Genetic characterization of North American populations of the wheat curl mite (Aceria tosichella) and dry bulb mite (Aceria tulipae) Author
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/12/2012
Publication Date: 10/22/2012
Publication URL: http://handle.nal.usda.gov/10113/55925
Citation: Hein, G.L., French, R.C., Siriwetwiwat, B., Amrine, J.W. 2012. Genetic characterization of North American populations of the wheat curl mite (Aceria tosichella) and dry bulb mite (Aceria tulipae). Journal of Economic Entomology. 105: 1801-1808. Interpretive Summary: The wheat curl mite transmits three economically important wheat viruses (wheat streak mosaic virus, high plains virus and triticum mosaic virus) in the Great Plains. Deploying mite-resistant wheat can be one way to manage these virus diseases. However, biological differences have been noted among wheat curl mite populations, complicating efforts to develop new mite-resistant wheat varieties. Molecular markers were identified which are capable of genetically distinguishing two types of wheat mites. These two mite types have distinct biological properties such as how well they can transmit each of the three wheat viruses. These same molecular markers were used to show that the dry bulb mite, which historically had been confused with the wheat curl mite, is in fact a distinct species. These results will aid entomologists studying mite biology and developing mite-resistant wheat. These results also will be useful to plant pathologists studying wheat virus epidemiology.
Technical Abstract: The wheat curl mite, Aceria tosichella Keifer, transmits at least three harmful viruses, wheat streak mosaic virus (WSMV), high plains virus (HPV), and Triticum mosaic virus (TriMV) to wheat (Triticum aestivum L.) throughout the Great Plains. This virus complex is considered to be the most serious disease of winter wheat in the western Great Plains. One component of managing this disease has been developing mite resistance in wheat; however, identification of mite biotypes has complicated deployment and stability of resistance. This biotypic variability in mites and differential virus transmission by different mite populations underscores the need to better understand mite identity. However, A. tosichella has a history of serious taxonomic confusion, especially as it relates to A. tulipae Keifer, the dry bulb mite. Molecular techniques were used to genetically characterize multiple A. tosichella populations and compare them to populations of A. tulipae. Mites from these populations were PCR amplified and the ribosomal ITS2 region sequenced. These results indicated limited variability between these two species, but two distinct types within A. tosichella were found that corresponded to previous work with Australian mite populations. Further work using sequencing of several mitochondrial DNA genes also demonstrated two distinct types of A. tosichella populations. Furthermore, the separation between these two A. tosichella types is comparable to their separation with A. tulipae, indicating that species scale differences exist between these two types of A. tosichella. These genetic differences correspond to important biological differences between the types (e.g. biotypic and virus transmission differences). In light of these differences, it is important that future studies on biological response differences account for these mite differences.