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ARS Home » Southeast Area » Stoneville, Mississippi » Southern Insect Management Research » Research » Publications at this Location » Publication #375213
Research Project: Innovative Strategies for Insect Resistance Management in Bt Cotton

Location: Southern Insect Management Research

Title: ABC transporter mutations in Cry1F-resistant fall armyworm (Spodoptera frugiperda) do not result in altered susceptibility to selected small molecule pesticides

Author
item ABDELGAFFAR, HEBA - University Of Tennessee
item Perera, Omaththage
item JURAT-FUENTES, JUAN LUIS - University Of Tennessee

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/21/2020
Publication Date: 9/28/2020
Citation: Abdelgaffar, H., Perera, O.P., Jurat-Fuentes, J. 2020. ABC transporter mutations in Cry1F-resistant fall armyworm (Spodoptera frugiperda) do not result in altered susceptibility to selected small molecule pesticides. Pest Management Science. https://doi.org/10.1002/ps.6106.
DOI: https://doi.org/10.1002/ps.6106

Interpretive Summary: Fall armyworm, Spodoptera frugiperda¸ has developed resistance to some of the Bacillus thuringiensis toxins used in transgenic crops. Resistance in fall armyworm to corn producing the Cry1F, Cry1Ab and Cry1A.105 proteins have been described in the western hemisphere. Studies have shown that alterations in an ABC transporter subfamily C2 (SfABCC2) gene was responsible for resistance to Cry proteins. Importantly, fall armyworm resistance to Cry1F corn in Puerto Rico was also shown to be associated with lower susceptibility to synthetic pesticides. Marginal but significantly reduced susceptibility to bifenthrin and increased susceptibility to spinetoram in a Cry1F-resitant S. frugiperda strain from Puerto Rico was observed in this research. Because resistance to Cry1F in this strain is linked to a mutation in SfABCC2, gene editing by CRISPR/Cas9 was used to create a SfABCC2 knockout in a laboratory reference strain. When compared to the parental reference, the knockout strain displayed 25-fold resistance to Cry1F but no alteration in susceptibility to synthetic pesticides. We conclude that Cry1F resistance due to alterations in SfABCC2 does not affect susceptibility to synthetic pesticides.

Technical Abstract: Transgenic crops producing Cry and Vip3 insecticidal proteins from the bacterium Bacillus thuringiensis are used for effective control of the fall armyworm, Spodoptera frugiperda J. E. Smith. However, cases of practical S. frugiperda resistance to transgenic corn producing the Cry1F, Cry1Ab and Cry1A.105 proteins have been described in the Western hemisphere. When studied, resistance to transgenic corn in S. frugiperda always involves alterations in an ABC transporter subfamily C2 (SfABCC2) gene. Importantly, S. frugiperda resistance to Cry1F corn in Puerto Rico was previously associated with lower susceptibility to synthetic pesticides. In this work, we detected marginal but significantly reduced susceptibility to bifenthrin and increased susceptibility to spinetoram in a Cry1F-resitant S. frugiperda strain from Puerto Rico. Because resistance to Cry1F in this strain is linked to a mutation in SfABCC2, we used gene editing by CRISPR/Cas9 to create a SfABCC2 knockout in a laboratory reference strain. When compared to the parental reference, the knockout strain displayed 25-fold resistance to Cry1F but no alteration in susceptibility to synthetic pesticides. These results support that resistance to Cry1F linked to alterations in SfABCC2 does not affect susceptibility to synthetic pesticides.