International Journal of Molecular Sciences Article Multiple Known Mechanisms and a Possible Role of an Enhanced Immune System in Bt-Resistance in a Field Population of the Bollworm, Helicoverpa zea: Differences in Gene Expression with RNAseq Roger D. Lawrie 1,2 , Robert D. Mitchell III 3, Jean Marcel Deguenon 2, Loganathan Ponnusamy 2 , Dominic Reisig 4, Alejandro Del Pozo-Valdivia 4, Ryan W. Kurtz 5 and R. Michael Roe 1,2,* 1 Department of Biology/Environmental and Molecular Toxicology Program, 850 Main Campus Dr, North Carolina State University, Raleigh, NC 27695, USA;
[email protected] 2 Department of Entomology and Plant Pathology, Campus Box 7647, 3230 Ligon Street, North Carolina State University, Raleigh, NC 27695, USA;
[email protected] (J.M.D.);
[email protected] (L.P.) 3 Knipling-Bushland US Livestock Insects Research Laboratory Genomics Center, 2700 Fredericksburg Road, United States Department of Agriculture-Agricultural Research Service, Kerrville, TX 78028, USA;
[email protected] 4 Department of Entomology and Plant Pathology, Vernon G. James Research & Extension Center, 207 Research Station Road, Plymouth, NC 27962, USA;
[email protected] (D.R.);
[email protected] (A.D.P.-V.) 5 Cotton Incorporated, 6399 Weston Parkway, Cary, NC 27513, USA;
[email protected] * Correspondence:
[email protected]; Tel.: +1-919-515-4325 Received: 31 July 2020; Accepted: 1 September 2020; Published: 7 September 2020 Abstract: Several different agricultural insect pests have developed field resistance to Bt (Bacillus thuringiensis) proteins (ex. Cry1Ac, Cry1F, etc.) expressed in crops, including corn and cotton. In the bollworm, Helicoverpa zea, resistance levels are increasing; recent reports in 2019 show up to 1000-fold levels of resistance to Cry1Ac, a major insecticidal protein in Bt-crops.