Cry1F resistance in fall armyworm Spodoptera frugiperda: single gene versus pyramided Bt maize

PLoS One. 2014 Nov 17;9(11):e112958. doi: 10.1371/journal.pone.0112958. eCollection 2014.

Abstract

Evolution of insect resistance to transgenic crops containing Bacillus thuringiensis (Bt) genes is a serious threat to the sustainability of this technology. However, field resistance related to the reduced efficacy of Bt maize has not been documented in any lepidopteran pest in the mainland U.S. after 18 years of intensive Bt maize planting. Here we report compelling evidence of field resistance in the fall armyworm, Spodoptera frugiperda (J.E. Smith), to Cry1F maize (TC 3507) in the southeastern region of the U.S. An F2 screen showed a surprisingly high (0.293) Cry1F resistance allele frequency in a population collected in 2011 from non-Bt maize in south Florida. Field populations from non-Bt maize in 2012-2013 exhibited 18.8-fold to >85.4-fold resistance to purified Cry1F protein and those collected from unexpectedly damaged Bt maize plants at several locations in Florida and North Carolina had >85.4-fold resistance. In addition, reduced efficacy and control failure of Cry1F maize against natural populations of S. frugiperda were documented in field trials using Cry1F-based and pyramided Bt maize products in south Florida. The Cry1F-resistant S. frugiperda also showed a low level of cross-resistance to Cry1A.105 and related maize products, but not to Cry2Ab2 or Vip3A. The occurrence of Cry1F resistance in the U.S. mainland populations of S. frugiperda likely represents migration of insects from Puerto Rico, indicating the great challenges faced in achieving effective resistance management for long-distance migratory pests like S. frugiperda.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Bacillus thuringiensis / genetics*
  • Bacterial Toxins / genetics*
  • Disease Resistance*
  • Insect Control / methods
  • Plants, Genetically Modified*
  • Spodoptera / microbiology*
  • Zea mays / genetics*
  • Zea mays / parasitology*

Substances

  • Bacterial Toxins

Grants and funding

This project represents work supported by the Louisiana Soybean and Feed Grain Promotion Board, Monsanto Company, and Hatch funds from the USDA National Institute of Food and Agriculture. The funder Monsanto provided support in the form of salaries for the coauthor (G.P.H.), but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. All other funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the “author contributions” section. The authors also confirm that this does not alter their adherence to PLOS ONE policies on sharing data and materials. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by Louisiana State University Agricultural Center, University of Florida or the U.S. Department of Agriculture.