Validation of reference genes for gene expression studies in non viruliferous and viruliferous[i] Frankliniella occidentalis[i] (Thysanoptera: Thripidae)

Quantitative real-time PCR (qRT-PCR) is a powerful technique for measuring and evaluating gene expressions during different biological processes. To facilitate gene expression studies, normalization with respect to stable housekeeping genes (HKGs) is mandatory. T he western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae), the main vector of Tomato spotted wilt virus (TSWV), is a very destructive invasive species. In this study, expression profiles of 11 candidate HKGs, including β-actin ( Actin), α-tubulin (Tubulin), elongation factor 1 α (EF1A), vacuolar-typeH+-ATPase (ATPase), NADHubiquinone oxidoreductase (NADH), heat shock protein 60 (HSP60), heat shock protein 70 (HSP70), heat shock protein 90 (HSP90), ribosomal protein l32 (RPL32), 28S ribosomal RNA (28S), and 18S ribosomal RNA (18S), from nonviruliferous and viruliferous F. occidentalis were investigated. Four distinct algorithms, geNorm, Normfinder, BestKeeper, and the ΔCt method, were employed to determine the performance of these genes as endogenous controls under the virus condition. Based on RefFinder, which integrates all four analytical algorithms to compare and rank the candidates, HSP70 , HSP60, EF1A, and RPL32 were the most stable housekeeping genes. This work is the initial first step to establish a standardized qRT-PCR analysis in F. occidentalis. Additionally, this study lays a foundation for the research in the interactions between TSWV and F. occidentalis.