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RNA interference of two glutathione S‐transferase genes, Diaphorina citri DcGSTe2 and DcGSTd1 , increases the susceptibility of Asian citrus psyllid (Hemiptera: Liviidae) to the pesticides fenpropathrin and thiamethoxam
Author(s) -
Yu Xiudao,
Killiny Nabil
Publication year - 2018
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.4747
Subject(s) - diaphorina citri , biology , rna interference , thiamethoxam , gene knockdown , glutathione s transferase , gene , hemiptera , rna silencing , chlorpyrifos , genetics , botany , rna , pesticide , glutathione , biochemistry , enzyme , imidacloprid , ecology
BACKGROUND The Asian citrus psyllid, Diaphorina citri Kuwayama, is an important agricultural pest of citrus globally. Foliar application of chemical insecticides is the most widely used option for reducing D. citri populations. Knockdown of glutathione S‐transferase ( GST ) in several insect species leads to increased susceptibility to insecticides; however, information about the detoxifying role of GST genes in D. citri is unavailable. RESULTS Via a sequence homology search, we isolated and characterized three DcGST genes ( DcGSTd1 , DcGSTe1 and DcGSTe2 ) from D. citri . Phylogenetic analysis grouped DcGSTd1 into the delta class of GST genes, whereas DcGSTe1 and DcGSTe2 were clustered in the epsilon clade. Gene expression analysis revealed that chlorpyrifos treatment increased the mRNA levels of DcGSTe1 and fenpropathrin enhanced the expression level of DcGSTd1 , while DcGSTe2 was significantly up‐regulated after exposure to thiamethoxam at a dose of 30% lethal concentration (LC30). RNA interference (RNAi) of DcGSTe2 and DcGSTd1 followed by an insecticide bioassay increased the mortalities of thiamethoxam‐treated psyllids by 23.0% and fenpropathrin‐treated psyllids by 15.0%. In contrast, knockdown of DcGSTe1 did not significantly increase the susceptibility of D. citri to any of these three insecticides. Further, feeding with double‐stranded RNA (ds DcGSTe2‐d1 ) interfusion co‐silenced DcGSTe2 and DcGSTd1 expression in D. citri , and led to an increase of susceptibility to both fenpropathrin and thiamethoxam. CONCLUSION The findings suggest that DcGSTe2 and DcGSTd1 play unique roles in detoxification of the pesticides thiamethoxam and fenpropathrin. In addition, co‐silencing by creating a well‐designed dsRNA interfusion against multiple genes was a good RNAi strategy in D. citri . © 2017 Society of Chemical Industry