Diversity of Vip3Aa resistance mechanisms in fall armyworm (Spodoptera frugiperda)

Sunday, November 10, 2024

11:05 AM – 11:20 AM MST

Location: Phoenix Convention Center, 127 A, PCC

Presenting Author(s)

Rajeev Roy

Graduate Student
University of Tennessee
Knoxville, Tennessee

Co-Author(s)

DK

Dawson Kerns

University of Tennessee
Knoxville, Tennessee
FH

Fangneng Huang

Professor
Louisiana State University
Baton Rouge, Louisiana
FY

Fei Yang

Assistant Professor
University of Minnesota
Saint Paul, Minnesota
David L. Kerns

Texas A&M University
College Station, Texas
Juan Luis Jurat-Fuentes (he/him/his)

Professor
University of Tennessee
Knoxville, Tennessee

The Vip3Aa insecticidal protein from the bacterium Bacillus thuringiensis remains the most effective plant-incorporated protectant (PIP) against fall armyworm (FAW, Spodoptera frugiperda). The successful isolation of Vip3Aa-resistant alleles from field FAW populations suggests the imminent development of field resistance. The availability of Vip3Aa-resistant FAW strains provides an opportunity to identify resistance mechanisms and genes involved. In this study, we compared the mechanism of resistance to Vip3Aa in FAW strains from Louisiana (LA-RR) and Texas (TX-RR). The experimental approach involved comparing Vip3Aa proteolytic activation and further downstream processes in the Vip3Aa mode of action between resistant and reference susceptible FAW strains. Findings from these experiments were further validated with transcriptomic profiling of gene expression and bioassays with protoxin and in vitro-activated Vip3Aa toxin. Results identified different mechanisms of resistance in the strains, supporting diverse mechanistic basis of resistance to Vip3Aa in FAW. The information generated from this study assists in the development of improved strategies to delay and overcome resistance to Vip3Aa in FAW populations.