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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Insects and Horticulture Research » Research » Publications at this Location » Publication #366104
Research Project: Exotic Whitefly Pests of Vegetables and Ornamental Plants

Location: Subtropical Insects and Horticulture Research

Title: Unexpected high intragenomic variation in two of three major pest thrips species does not affect ribosomal internal transcribed spacer 2 (ITS2) utility for thrips identification

Author
item KUMAR, VIVEK - University Of Florida
item Dickey, Aaron
item SEAL, DAKSHINA - University Of Florida
item Shatters, Robert - Bob
item OSBORNE, LANCE - University Of Florida
item McKenzie, Cindy

Submitted to: Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2019
Publication Date: 11/17/2019
Citation: Kumar, V., Dickey, A.M., Seal, D., Shatters, R.G., Osborne, L., McKenzie, C.L. 2019. Unexpected high intragenomic variation in two of three major pest thrips species does not affect ribosomal internal transcribed spacer 2 (ITS2) utility for thrips identification [abstract]. Entomological Society of America Annual Meeting. D#3467.

Interpretive Summary:

Technical Abstract: The mitochondrial gene mtCO1 and the internal transcribed spacer (ITS) region of the ribosomal DNA are among the most widely used molecular markers for insect taxonomic characterization. Three economically important species of thrips, Scirtothrips dorsalis, Thrips palmi, and Frankliniella occidentalis were selected to examine the extent of intragenomic and intergenomic variation within these two marker regions in the family Thripidae. The within species intragenomic and intergenomic variation were assessed by cloning and sequencing Polymerase chain reaction-amplified copies of these two genes. Intragenomic and intergenomic variation were detected in both markers in three thrips species and intergenomic variation was significantly higher than intragenomic variation for both genes in all three species. For ITS2,intragenomic variation ranged between 0.20 - 3.82 percent, 0.18 - 2.84 percent, 0.44 -1.10 percent for Scirtothrips dorsalis, Thrips palmi and Frankliniella occidentalis, respectively and intergenomic variation ranged between 0.0 - 3.82 percent, 0.0 - 3.01 percent, 0.0 - 1.77 percent for Scirtothrips dorsalis, Thrips palmi and Frankliniella occidentalis, respectively. Significantly higher amounts of intragenomic variation were observed for ITS2 than mtCO1 in Scirtothrips dorsalis and Thrips palmi. In all the three thrips species no sex- based clustering of haplotypes was observed in ITS2 and mtCO1. While our results validate the utility of ITS2 for Frankliniella occidentalis, extreme caution should be used in applying this marker to taxonomic characterization of other thrips species. The mitochondrial gene mtCO1 should be considered a preferable marker for diagnostics over Internal transcribed spacer (ITS) in two out of three thrips species due to significantly lower levels of potentially problematic intragenomic variation. Possible reasons for discrepancies in intragenomic variation among genes are discussed.