Comparison of five DNA extracting protocols from Typhlodromus (Anthoseius) bagdasarjani Wainsten and Arutunjan (Acari: Phytoseiidae)

Obtaining clean DNA from mites to be used in molecular studies has always been a challenging task. In this study, five protocols (CTAB-based handmade kit, salting out protocol, STE protocol, modified CTAB-based protocol and wizard Genomic DNA purification kit) were evaluated to extract DNA from Typhlodromus (Anthoseius) bagdasarjani. Quantitative and qualitative analyses of the DNA concentrations and a comparison between the ratio of absorption of wavelength from 260 to 280 nm in a completely randomized split plot design for five extraction protocols and three levels of 1, 5, 10 mites were performed. PCR protocol was used to examine the amplification of the ITS1 fragment from the specimens. The results showed that wizard kit and CTAB modified protocol were the bests. However, economically, modified CTAB-based protocol is the best choice for extensive experiments, since this protocol allows extracting DNA from an individual mite and provides the highest concentration DNA (143.35±0.85ng) and the best OD (1.80±0.03) for molecular studies.

Differential Transmission of Two Isolates of Wheat streak mosaic virus by Five Wheat Curl Mite Populations

Wheat streak mosaic virus (WSMV), type member of the genus Tritimovirus in the family Potyviridae, is an economically important virus causing annual average yield losses of approximately 2 to 3% in winter wheat across the Great Plains. The wheat curl mite (WCM), Aceria tosichella, transmits WSMV along with two other viruses found throughout the Great Plains of the United States. Two common genotypes of WSMV (Sidney 81 and Type) in the United States share 97.6% nucleotide sequence identity but their transmission relationships with the WCM are unknown. The objective of this study was to determine transmission of these two isolates of WSMV by five WCM populations (‘Nebraska’, ‘Montana’, ‘South Dakota’, ‘Type 1’, and ‘Type 2’). Nonviruliferous mites from each population were reared on wheat source plants mechanically inoculated with either Sidney 81 or Type WSMV isolates. For each source plant, individual mites were transferred to 10 separate test plants and virus transmission was determined by a double-antibody sandwich enzyme-linked immunosorbent assay. Source plants were replicated nine times for each treatment (90 individual mite transfers). Results indicate that three mite populations transmitted Sidney 81 at higher rates compared with Type. Two mite populations (Nebraska and Type 2) transmitted Sidney 81 and Type at higher rates compared with the other three populations. Results from this study demonstrate that interactions between virus isolates and mite populations influence the epidemiology of WSMV.