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Research Project: Improved Biologically-Based Methods for Management of Native and Invasive Crop Insect Pests

Location: Insect Behavior and Biocontrol Research

Title: Large genomic deletion linked to field-evolved resistance to Cry1F corn in fall armyworm (Spodoptera frugiperda) from Florida

Author
item BANEJEE, R - University Of Tennessee
item PLACIDI DE BORTOLI, C - University Of Tennessee
item HUANG, F - Louisana State University
item LAMOUR, K - University Of Tennessee
item Meagher, Robert - Rob
item BUNTIN, G - University Of Georgia
item Ni, Xinzhi
item REAY-JONES, F - Clemson University
item STEWARD, S - University Of Tennessee
item JURAT-FUENTES, J - University Of Tennessee

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/27/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary: The fall armyworm (Spodoptera frugiperda) is a serious worldwide moth pest of many food and fiber staple crops. In the Americas, transgenic corn and cotton producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) has controlled and reduced the damage caused by this pest. However, some field populations of fall armyworm in both North and South America have developed resistance to Bt corn when it produces the Cry1F insecticidal protein. Research by scientists from the University of Tennessee, Louisiana State University, University of Georgia, Clemson University, along with an USDA-ARS CMAVE, Gainesville, FL entomologist and USDA-ARS Crop Genetics and Research, Tifton, GA entomologist, showed that resistance found in a Florida population was genetically different (gene fusion event) than populations in other southeastern states and in Puerto Rico. To our knowledge, this is the first report of a gene fusion event being involved in resistance to a Bt insecticidal protein. These results are important because they indicate that resistance to Bt in Florida is not related to resistance found in other areas and is not a result of migration.

Technical Abstract: The fall armyworm (Spodoptera frugiperda) is a highly polyphagous lepidopteran pest of relevant food and fiber staple crops. In the Americas, transgenic corn and cotton producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) has controlled and reduced the damage caused by S. frugiperda. However, cases of field-evolved S. frugiperda resistance to Bt corn producing the Cry1F insecticidal protein have been documented in North and South America. When characterized, field resistance to Cry1F is linked to insertions and mutations resulting in a modified or truncated ABC transporter subfamily C2 (SfABCC2) protein that serves as Cry1F receptor in susceptible S. frugiperda. In this work, we present a gene fusion event involving the SfABCC2 and an ABC transporter gene subfamily 3 –like gene (SfABCC3) as linked to resistance to Cry1F corn in a S. frugiperda strain from Florida (FL39). Monitoring for this gene fusion using a discriminatory PCR reaction in field-collected S. frugiperda detected individuals carrying this allele in Florida, but not in surrounding states or in Puerto Rico. To our knowledge, this is the first report of a gene fusion being involved in resistance to a Bt insecticidal protein.