Invasive Species Compendium

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Abstract

The responses of detoxification enzyme and gene expression in western flower thrips, Frankliniella occidentalis, to new challenging hosts.

Abstract

The western flower thrips, Frankliniella occidentalis (Pergande) is an economically important invasive pest. It shows different preferences for various vegetables. This study investigated the responses of detoxification enzyme and gene expression in F. occidentalis when thrips were transferred from kidney bean pods to new hosts kidney bean plant and broad bean plant. Variations in the activities and gene expressions of carboxylesterase (CarE), glutathione S-transferase (GSTs) and cytochrome P450 monooxygenases (P450) in F. occidentalis in F1, F2 and F3 generations were determined on new hosts. The results showed that activities and gene expression of detoxification enzymes were significantly influenced by the host, stage and generation, and there were significant interactions in most situations between the two factors and among three factors. After transferring to kidney bean plant, the activities of the detoxification enzymes exhibited a similar pattern of variation, with maximal levels observed in the F1 generation. By the F3 generation, activities of CarE and GSTs in 2nd instar larvae remained higher than the control group. When F. occidentalis were transferred to broad bean plant, the activities of CarE and P450 in 2nd instar larvae and adults also rose. The expressions of CL4503. Contig2 in F. occidentalis significantly decreased after transfer to kidney bean plants, while it was significantly up-regulated after thrips were transferred to broad bean plant. However, the expressions of CL992.contig14, CL1914. Contig2 and Unigene18748 in three generations significantly decreased. The results indicated that F. occidentalis was able to rapidly respond by altering the activities of its detoxification enzymes and related genes expressions, thereby gradually adapting to different hosts in each successive generation.