1
|
Bryant TB, Greene JK, Reisig D, Reay-Jones FPF. Continued decline in sublethal effects of Bt toxins on Helicoverpa zea (Lepidoptera: Noctuidae) in field corn. JOURNAL OF ECONOMIC ENTOMOLOGY 2024; 117:1876-1883. [PMID: 38984916 DOI: 10.1093/jee/toae152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 06/11/2024] [Accepted: 06/22/2024] [Indexed: 07/11/2024]
Abstract
The majority of field corn, Zea mays L., in the southeastern United States has been genetically engineered to express insecticidal toxins produced by the soil bacterium, Bacillus thuringiensis (Bt). Field corn is the most important mid-season host for corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), which has developed resistance to all Cry toxins in Bt corn. From 2020 to 2023, corn earworm pupae were collected from early- and late-planted pyramided hybrids expressing Bt toxins and non-Bt near-isolines in North and South Carolina (16 trials). A total of 5,856 pupae were collected across all trials, with 55 and 88% more pupae collected in later-planted trials relative to early plantings in North and South Carolina, respectively. Only 20 pupae were collected from hybrids expressing Cry1F + Cry1Ab + Vip3A20 across all trials. Averaged across trials, Cry1A.105 + Cry2Ab2 hybrids reduced pupal weight by 6 and 9% in North and South Carolina, respectively, relative to the non-Bt near-isoline. Cry1F + Cry1Ab hybrids reduced pupal weight on average by 3 and 8% in North and South Carolina, respectively, relative to the non-Bt near-isoline. The impact of the Bt toxins on pupal weight varied among trials. When combined with data from 2014 to 2019 from previous studies, a significant decline in the percent reduction in pupal weight over time was found in both states and hybrid families. This study demonstrates a continued decline in the sublethal impacts of Bt toxins on corn earworm, emphasizing the importance of insect resistance management practices.
Collapse
Affiliation(s)
- Tim B Bryant
- Department of Plant and Environmental Sciences, Pee Dee Research and Education Center, Clemson University, Florence, SC, USA
| | - Jeremy K Greene
- Department of Plant and Environmental Sciences, Edisto Research and Education Center, Clemson University, Blackville, SC, USA
| | - Dominic Reisig
- Department of Entomology and Plant Pathology, Vernon G. James Research and Extension Center, North Carolina State University, Plymouth, NC, USA
| | - Francis P F Reay-Jones
- Department of Plant and Environmental Sciences, Pee Dee Research and Education Center, Clemson University, Florence, SC, USA
| |
Collapse
|
2
|
Bryant TB, Greene JK, Reay-Jones FPF. Competition between brown stink bug (Hemiptera: Pentatomidae) and corn earworm (Lepidoptera: Noctuidae) in field corn. ENVIRONMENTAL ENTOMOLOGY 2024; 53:860-869. [PMID: 38965911 DOI: 10.1093/ee/nvae065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 06/06/2024] [Accepted: 06/18/2024] [Indexed: 07/06/2024]
Abstract
Interspecific competition is an important ecological concept which can play a major role in insect population dynamics. In the southeastern United States, a complex of stink bugs (Hemiptera: Pentatomidae), primarily the brown stink bug, Euschistus servus (Say), and corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), are the 2 most common pests of field corn, Zea mays L. (Poales: Poaceae). Stink bugs have the greatest potential for economic injury during the late stages of vegetative corn development when feeding can result in deformed or "banana-shaped" ears and reduced grain yield. Corn earworm moths lay eggs on corn silks during the first stages of reproductive development. A 2-year field study was conducted to determine the impact of feeding by the brown stink bug during late-vegetative stages on subsequent corn earworm oviposition, larval infestations, and grain yield. Brown stink bug feeding prior to tasseling caused deformed ears and reduced overall grain yield by up to 92%. Across all trials, varying levels of brown stink bug density and injury reduced the number of corn earworm larvae by 29-100% and larval feeding by 46-85%. Averaged across brown stink bug densities, later planted corn experienced a 9-fold increase in number of corn earworm larvae. This is the first study demonstrating a competitive interaction between these major pests in a field corn setting, and these results have potential implications for insect resistance management.
Collapse
Affiliation(s)
- Tim B Bryant
- Department of Plant and Environmental Sciences, Pee Dee Research and Education Center, Clemson University, Florence, SC, USA
| | - Jeremy K Greene
- Department of Plant and Environmental Sciences, Edisto Research and Education Center, Clemson University, Blackville, SC, USA
| | - Francis P F Reay-Jones
- Department of Plant and Environmental Sciences, Pee Dee Research and Education Center, Clemson University, Florence, SC, USA
| |
Collapse
|
3
|
Martin CL, Hill JH, Aller SG. Host Tropism and Structural Biology of ABC Toxin Complexes. Toxins (Basel) 2024; 16:406. [PMID: 39330864 PMCID: PMC11435725 DOI: 10.3390/toxins16090406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2024] [Revised: 09/12/2024] [Accepted: 09/17/2024] [Indexed: 09/28/2024] Open
Abstract
ABC toxin complexes are a class of protein toxin translocases comprised of a multimeric assembly of protein subunits. Each subunit displays a unique composition, contributing to the formation of a syringe-like nano-machine with natural cargo carrying, targeting, and translocation capabilities. Many of these toxins are insecticidal, drawing increasing interest in agriculture for use as biological pesticides. The A subunit (TcA) is the largest subunit of the complex and contains domains associated with membrane permeation and targeting. The B and C subunits, TcB and TcC, respectively, package into a cocoon-like structure that contains a toxic peptide and are coupled to TcA to form a continuous channel upon final assembly. In this review, we outline the current understanding and gaps in the knowledge pertaining to ABC toxins, highlighting seven published structures of TcAs and how these structures have led to a better understanding of the mechanism of host tropism and toxin translocation. We also highlight similarities and differences between homologues that contribute to variations in host specificity and conformational change. Lastly, we review the biotechnological potential of ABC toxins as both pesticides and cargo-carrying shuttles that enable the transport of peptides into cells.
Collapse
Affiliation(s)
- Cole L Martin
- Graduate Biomedical Sciences Pathobiology, Physiology and Pharmacology Theme, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - John H Hill
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Stephen G Aller
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| |
Collapse
|
4
|
Liu Z, Liao C, Zou L, Jin M, Shan Y, Quan Y, Yao H, Zhang L, Wang P, Liu Z, Wang N, Li A, Liu K, Tabashnik BE, Heckel DG, Wu K, Xiao Y. Retrotransposon-mediated disruption of a chitin synthase gene confers insect resistance to Bacillus thuringiensis Vip3Aa toxin. PLoS Biol 2024; 22:e3002704. [PMID: 38954724 PMCID: PMC11249258 DOI: 10.1371/journal.pbio.3002704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 07/15/2024] [Accepted: 06/07/2024] [Indexed: 07/04/2024] Open
Abstract
The vegetative insecticidal protein Vip3Aa from Bacillus thuringiensis (Bt) has been produced by transgenic crops to counter pest resistance to the widely used crystalline (Cry) insecticidal proteins from Bt. To proactively manage pest resistance, there is an urgent need to better understand the genetic basis of resistance to Vip3Aa, which has been largely unknown. We discovered that retrotransposon-mediated alternative splicing of a midgut-specific chitin synthase gene was associated with 5,560-fold resistance to Vip3Aa in a laboratory-selected strain of the fall armyworm, a globally important crop pest. The same mutation in this gene was also detected in a field population. Knockout of this gene via CRISPR/Cas9 caused high levels of resistance to Vip3Aa in fall armyworm and 2 other lepidopteran pests. The insights provided by these results could help to advance monitoring and management of pest resistance to Vip3Aa.
Collapse
Affiliation(s)
- Zhenxing Liu
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Chongyu Liao
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Luming Zou
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Minghui Jin
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Yinxue Shan
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Yudong Quan
- The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, China
| | - Hui Yao
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Lei Zhang
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Peng Wang
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Zhuangzhuang Liu
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Na Wang
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Anjing Li
- Institute of Entomology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Kaiyu Liu
- Institute of Entomology, School of Life Sciences, Central China Normal University, Wuhan, China
| | - Bruce E. Tabashnik
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - David G. Heckel
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
- Department of Entomology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Kongming Wu
- The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, China
| | - Yutao Xiao
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| |
Collapse
|
5
|
Reisig D, Heiniger R. Yield analysis and corn earworm feeding in Bt and non-Bt corn hybrids across diverse locations. JOURNAL OF ECONOMIC ENTOMOLOGY 2024:toae120. [PMID: 38832396 DOI: 10.1093/jee/toae120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 05/01/2024] [Accepted: 05/17/2024] [Indexed: 06/05/2024]
Abstract
Corn, Zea mays L. (Poales: Poaceae), growers in the US Cotton Belt are required to plant 20% of total corn acres to non-Bt hybrids for resistance management (non-Bt refuge). Most growers do not meet this requirement, in part, because they perceive non-Bt hybrids to yield less than Bt hybrids. We planted multiple non-Bt and Bt hybrids from a single company in small-plot replicated trials at a single location from 2019 to 2023, as well as in small-plot replicated trials at multiple locations during 2022 and 2023. In the single location, we measured kernel injury from corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), and we recorded yield at all locations. In the single location trial, yields only separated among hybrids in 3 out of 5 years. In the multiple location trial, yields were variable between both years. We found that Bt hybrids tended to yield higher than non-Bt hybrids overall, but this was influenced by the inclusion of non-Bt hybrids that had a lower overall genetic yield potential in the environments we tested them in. In both tests, when hybrids were analyzed during each year, both Bt and non-Bt hybrids were among the statistically highest yielders. Our study demonstrates the importance of comparing multiple Bt and non-Bt hybrids to draw yield comparisons. This highlights the need for corn seed company breeders to put effort into improving yield for non-Bt hybrids. Hopefully this effort will translate into increased planting of non-Bt refuge corn for growers in the US Cotton Belt.
Collapse
Affiliation(s)
- Dominic Reisig
- Department of Entomology and Plant Pathology, NC State University, 207 Research Station Road, Plymouth, NC 27962, USA
| | - Ryan Heiniger
- Department of Crop and Soil Sciences, NC State University, Nelson Hall, 3709 Hillsboro Street, Raleigh, NC 27607, USA
| |
Collapse
|
6
|
Yang F, Head GP, Kerns DD, Jurat-Fuentes JL, Santiago-González JC, Kerns DL. Diverse genetic basis of Vip3Aa resistance in five independent field-derived strains of Helicoverpa zea in the US. PEST MANAGEMENT SCIENCE 2024; 80:2796-2803. [PMID: 38327120 DOI: 10.1002/ps.7988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 01/19/2024] [Accepted: 01/23/2024] [Indexed: 02/09/2024]
Abstract
BACKGROUND Practical resistance of Helicoverpa zea to Cry proteins has become widespread in the US, making Vip3Aa the only effective Bacillus thuringiensis (Bt) protein for controlling this pest. Understanding the genetic basis of Vip3Aa resistance in H. zea is essential in sustaining the long-term efficacy of Vip3Aa. The objectives of this study were to characterize the inheritance of Vip3Aa resistance in four distinct field-derived H. zea strains (M1-RR, AC4-RR, R2-RR and R15-RR), and to test for shared genetic basis among these strains and a previously characterized Texas resistant strain (LT#70-RR). RESULTS Maternal effects and sex linkage were absent, and the effective dominance level (DML) was 0.0 across Vip3Aa39 concentrations ranging from 1.0 to 31.6 μg cm-2, in all H. zea resistant strains. Mendelian monogenic model tests indicated that Vip3Aa resistance in each of the four strains was controlled by a single gene. However, interstrain complementation tests indicated that three distinct genetic loci are involved in Vip3Aa resistance in the five resistant H. zea strains: one shared by M1-RR and LT#70-RR; another shared by R2-RR and R15-RR; and a distinct one for AC4-RR. CONCLUSION Results of this study indicate that Vip3Aa resistance in all H. zea strains was controlled by a single, recessive and autosomal gene. However, there were three distinct genetic loci associated with Vip3Aa resistance in the five resistant H. zea strains. The information generated from this study is valuable for exploring mechanisms of Vip3Aa resistance, monitoring the evolution of Vip3Aa resistance, and devising effective strategies for managing Vip3Aa resistance in H. zea. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Collapse
Affiliation(s)
- Fei Yang
- Department of Entomology, Texas A&M University, College Station, Texas, USA
- Department of Entomology, University of Minnesota, Saint Paul, Minnesota, USA
| | | | - Dawson D Kerns
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee, USA
| | - Juan Luis Jurat-Fuentes
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee, USA
| | | | - David L Kerns
- Department of Entomology, Texas A&M University, College Station, Texas, USA
| |
Collapse
|
7
|
Tran GH, Tran TH, Pham SH, Xuan HL, Dang TT. Cyclotides: The next generation in biopesticide development for eco-friendly agriculture. J Pept Sci 2024; 30:e3570. [PMID: 38317283 DOI: 10.1002/psc.3570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/09/2024] [Accepted: 01/12/2024] [Indexed: 02/07/2024]
Abstract
Chemical pesticides remain the predominant method for pest management in numerous countries. Given the current landscape of agriculture, the development of biopesticides has become increasingly crucial. The strategy empowers farmers to efficiently manage pests and diseases, while prioritizing minimal adverse effects on the environment and human health, hence fostering sustainable management. In recent years, there has been a growing interest and optimism surrounding the utilization of peptide biopesticides for crop protection. These sustainable and environmentally friendly substances have been recognized as viable alternatives to synthetic pesticides due to their outstanding environmental compatibility and efficacy. Numerous studies have been conducted to synthesize and identify peptides that exhibit activity against significant plant pathogens. One of the peptide classes is cyclotides, which are cyclic cysteine-rich peptides renowned for their wide range of sequences and functions. In this review, we conducted a comprehensive analysis of cyclotides, focusing on their structural attributes, developmental history, significant biological functions in crop protection, techniques for identification and investigation, and the application of biotechnology to enhance cyclotide synthesis. The objective is to emphasize the considerable potential of cyclotides as the next generation of plant protection agents on the global scale.
Collapse
Affiliation(s)
- Gia-Hoa Tran
- Institute of Applied Materials Science, Vietnam Academy of Science and Technology, Ho Chi Minh City, Viet Nam
- Institute of Biotechnology and Food Technology, Industrial University of Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Thi-Huyen Tran
- Institute of Biotechnology and Food Technology, Industrial University of Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Son H Pham
- Institute of Applied Materials Science, Vietnam Academy of Science and Technology, Ho Chi Minh City, Viet Nam
| | - Huy Luong Xuan
- Faculty of Pharmacy, PHENIKAA University, Hanoi, Vietnam
| | - Tien T Dang
- Institute of Applied Materials Science, Vietnam Academy of Science and Technology, Ho Chi Minh City, Viet Nam
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Viet Nam
| |
Collapse
|
8
|
Kerns DD, Yang F, Kerns DL, Stewart SD, Jurat-Fuentes JL. Reduced toxin binding associated with resistance to Vip3Aa in the corn earworm ( Helicoverpa zea). Appl Environ Microbiol 2023; 89:e0164423. [PMID: 38014960 PMCID: PMC10734485 DOI: 10.1128/aem.01644-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 10/17/2023] [Indexed: 11/29/2023] Open
Abstract
IMPORTANCE Helicoverpa zea is a major crop pest in the United States that is managed with transgenic corn and cotton that produce insecticidal proteins from the bacterium, Bacillus thuringiensis (Bt). However, H. zea has evolved widespread resistance to the Cry proteins produced in Bt corn and cotton, leaving Vip3Aa as the only plant-incorporated protectant in Bt crops that consistently provides excellent control of H. zea. The benefits provided by Bt crops will be substantially reduced if widespread Vip3Aa resistance develops in H. zea field populations. Therefore, it is important to identify resistance alleles and mechanisms that contribute to Vip3Aa resistance to ensure that informed resistance management strategies are implemented. This study is the first report of reduced binding of Vip3Aa to midgut receptors associated with resistance.
Collapse
Affiliation(s)
- Dawson D. Kerns
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee, USA
| | - Fei Yang
- Department of Entomology, University of Minnesota, St. Paul, Minnesota, USA
| | - David L. Kerns
- Department of Entomology, Texas A&M University, College Station, Texas, USA
| | - Scott D. Stewart
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee, USA
| | - Juan Luis Jurat-Fuentes
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee, USA
| |
Collapse
|
9
|
Tabashnik BE. Cross-kingdom convergence provides promising proteins for pest control. Proc Natl Acad Sci U S A 2023; 120:e2316386120. [PMID: 37883418 PMCID: PMC10636295 DOI: 10.1073/pnas.2316386120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023] Open
|
10
|
Jin M, Shan Y, Peng Y, Wang W, Zhang H, Liu K, Heckel DG, Wu K, Tabashnik BE, Xiao Y. Downregulation of a transcription factor associated with resistance to Bt toxin Vip3Aa in the invasive fall armyworm. Proc Natl Acad Sci U S A 2023; 120:e2306932120. [PMID: 37874855 PMCID: PMC10622909 DOI: 10.1073/pnas.2306932120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 09/11/2023] [Indexed: 10/26/2023] Open
Abstract
Transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) have revolutionized control of some major pests. However, more than 25 cases of field-evolved practical resistance have reduced the efficacy of transgenic crops producing crystalline (Cry) Bt proteins, spurring adoption of alternatives including crops producing the Bt vegetative insecticidal protein Vip3Aa. Although practical resistance to Vip3Aa has not been reported yet, better understanding of the genetic basis of resistance to Vip3Aa is urgently needed to proactively monitor, delay, and counter pest resistance. This is especially important for fall armyworm (Spodoptera frugiperda), which has evolved practical resistance to Cry proteins and is one of the world's most damaging pests. Here, we report the identification of an association between downregulation of the transcription factor gene SfMyb and resistance to Vip3Aa in S. frugiperda. Results from a genome-wide association study, fine-scale mapping, and RNA-Seq identified this gene as a compelling candidate for contributing to the 206-fold resistance to Vip3Aa in a laboratory-selected strain. Experimental reduction of SfMyb expression in a susceptible strain using RNA interference (RNAi) or CRISPR/Cas9 gene editing decreased susceptibility to Vip3Aa, confirming that reduced expression of this gene can cause resistance to Vip3Aa. Relative to the wild-type promoter for SfMyb, the promoter in the resistant strain has deletions and lower activity. Data from yeast one-hybrid assays, genomics, RNA-Seq, RNAi, and proteomics identified genes that are strong candidates for mediating the effects of SfMyb on Vip3Aa resistance. The results reported here may facilitate progress in understanding and managing pest resistance to Vip3Aa.
Collapse
Affiliation(s)
- Minghui Jin
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies (Hainan), Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen518116, China
- The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing100193, China
| | - Yinxue Shan
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies (Hainan), Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen518116, China
| | - Yan Peng
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies (Hainan), Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen518116, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan430070, China
| | - Wenhui Wang
- The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing100193, China
| | - Huihui Zhang
- Institute of Entomology, School of Life Sciences, Central China Normal University, Wuhan430079, China
| | - Kaiyu Liu
- Institute of Entomology, School of Life Sciences, Central China Normal University, Wuhan430079, China
| | - David G. Heckel
- Department of Entomology, Max Planck Institute for Chemical Ecology, JenaD-07745, Germany
| | - Kongming Wu
- The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing100193, China
| | | | - Yutao Xiao
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies (Hainan), Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen518116, China
| |
Collapse
|
11
|
Carrière Y, Degain B, Unnithan GC, Tabashnik BE. Inheritance and fitness cost of laboratory-selected resistance to Vip3Aa in Helicoverpa zea (Lepidoptera: Noctuidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2023; 116:1804-1811. [PMID: 37555261 DOI: 10.1093/jee/toad145] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/22/2023] [Accepted: 07/10/2023] [Indexed: 08/10/2023]
Abstract
The polyphagous pest Helicoverpa zea (Lepidoptera: Noctuidae) has evolved practical resistance to transgenic corn and cotton producing Cry1 and Cry2 crystal proteins from Bacillus thuringiensis (Bt) in several regions of the United States. However, the Bt vegetative insecticidal protein Vip3Aa produced by Bt corn and cotton remains effective against this pest. To advance knowledge of resistance to Vip3Aa, we selected a strain of H. zea for resistance to Vip3Aa in the laboratory. After 28 generations of continuous selection, the resistance ratio was 267 for the selected strain (GA-R3) relative to a strain not selected with Vip3Aa (GA). Resistance was autosomal and almost completely recessive at a concentration killing all individuals from GA. Declines in resistance in heterogeneous strains containing a mixture of susceptible and resistant individuals reared in the absence of Vip3Aa indicate a fitness cost was associated with resistance. Previously reported cases of laboratory-selected resistance to Vip3Aa in lepidopteran pests often show partially or completely recessive resistance at high concentrations and fitness costs. Abundant refuges of non-Bt host plants can maximize the benefits of such costs for sustaining the efficacy of Vip3Aa against target pests.
Collapse
Affiliation(s)
- Yves Carrière
- Department of Entomology, University of Arizona, Tucson, AZ, USA
| | - Ben Degain
- Department of Entomology, University of Arizona, Tucson, AZ, USA
| | | | | |
Collapse
|
12
|
Marques LH, Ishizuka TK, Pereira RR, Istchuk AN, Rossetto J, Moscardini VF, E Silva OANB, Santos AC, Nowatzki T, Dahmer ML, Sethi A, Storer NP, Gontijo PC, Netto JC, Weschenfelder MAG, de Almeida PG, Bernardi O. Performance of cotton expressing Cry1Ac, Cry1F and Vip3Aa19 insecticidal proteins against Helicoverpa armigera, H. zea and their hybrid progeny, and evidence of reduced susceptibility of a field population of H. zea to Cry1 and Vip3Aa in Brazil. PLoS One 2023; 18:e0289003. [PMID: 37490504 PMCID: PMC10368247 DOI: 10.1371/journal.pone.0289003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 07/02/2023] [Indexed: 07/27/2023] Open
Abstract
The genetically modified cotton DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 expressing Cry1Ac, Cry1F and Vip3Aa19 from Bacillus thuringiensis Berliner (Bt) has been cultivated in Brazil since the 2020/2021 season. Here, we assessed the performance of DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton expressing Cry1Ac, Cry1F and Vip3Aa19 against Helicoverpa armigera (Hübner), Helicoverpa zea (Boddie), and their hybrid progeny. We also carried out evaluations with DAS-21023-5 × DAS-24236-5 cotton containing Cry1Ac and Cry1F. In leaf-disk bioassays, DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 was effective in controlling neonates from laboratory colonies of H. armigera, H. zea and the hybrid progeny (71.9%-100% mortality). On floral bud bioassays using L2 larvae, H. zea presented complete mortality, whereas H. armigera and the hybrid progeny showed <55% mortality. On DAS-21023-5 × DAS-24236-5 cotton, the mortality of H. armigera on leaf-disk and floral buds ranged from 60% to 73%, whereas mortality of hybrids was <46%. This Bt cotton caused complete mortality of H. zea larvae from a laboratory colony in the early growth stages, but mortalities were <55% on advanced growth stages and on floral buds. In field studies conducted from 2014 to 2019, DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton was also effective at protecting plants against H. armigera. In contrast, a population of H. zea collected in western Bahia in 2021/2022 on Bt cotton expressing Cry1 and Vip3Aa proteins, showed 63% mortality after 30 d, with insects developing into fifth and sixth instars, on DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton. We conclude that H. armigera, H. zea, and their hybrid progeny can be managed with DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton; however we found the first evidence in Brazil of a significant reduction in the susceptibility to DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 cotton of a population of H. zea collected from Bt cotton in Bahia in 2021/2022.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Mark L Dahmer
- Corteva Agriscience, Johnston, IA, United States of America
| | - Amit Sethi
- Corteva Agriscience, Johnston, IA, United States of America
| | | | - Pablo C Gontijo
- Instituto Federal Goiano (IF Goiano), Campus Rio Verde, Rio Verde, GO, Brazil
| | - Jacob C Netto
- Instituto Mato-grossense do Algodão (IMAmt), Primavera do Leste, MT, Brazil
| | | | | | - Oderlei Bernardi
- Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil
| |
Collapse
|
13
|
Dively GP, Kuhar TP, Taylor SV, Doughty H, Holmstrom K, Gilrein DO, Nault BA, Ingerson-Mahar J, Huseth A, Reisig D, Fleischer S, Owens D, Tilmon K, Reay-Jones F, Porter P, Smith J, Saguez J, Wells J, Congdon C, Byker H, Jensen B, DiFonzo C, Hutchison WD, Burkness E, Wright R, Crossley M, Darby H, Bilbo T, Seiter N, Krupke C, Abel C, Coates BS, McManus B, Fuller B, Bradshaw J, Peterson JA, Buntin D, Paula-Moraes S, Kesheimer K, Crow W, Gore J, Huang F, Ludwick DC, Raudenbush A, Jimenez S, Carrière Y, Elkner T, Hamby K. Extended Sentinel Monitoring of Helicoverpa zea Resistance to Cry and Vip3Aa Toxins in Bt Sweet Corn: Assessing Changes in Phenotypic and Allele Frequencies of Resistance. INSECTS 2023; 14:577. [PMID: 37504584 PMCID: PMC10380249 DOI: 10.3390/insects14070577] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/12/2023] [Accepted: 06/14/2023] [Indexed: 07/29/2023]
Abstract
Transgenic corn and cotton that produce Cry and Vip3Aa toxins derived from Bacillus thuringiensis (Bt) are widely planted in the United States to control lepidopteran pests. The sustainability of these Bt crops is threatened because the corn earworm/bollworm, Helicoverpa zea (Boddie), is evolving a resistance to these toxins. Using Bt sweet corn as a sentinel plant to monitor the evolution of resistance, collaborators established 146 trials in twenty-five states and five Canadian provinces during 2020-2022. The study evaluated overall changes in the phenotypic frequency of resistance (the ratio of larval densities in Bt ears relative to densities in non-Bt ears) in H. zea populations and the range of resistance allele frequencies for Cry1Ab and Vip3Aa. The results revealed a widespread resistance to Cry1Ab, Cry2Ab2, and Cry1A.105 Cry toxins, with higher numbers of larvae surviving in Bt ears than in non-Bt ears at many trial locations. Depending on assumptions about the inheritance of resistance, allele frequencies for Cry1Ab ranged from 0.465 (dominant resistance) to 0.995 (recessive resistance). Although Vip3Aa provided high control efficacy against H. zea, the results show a notable increase in ear damage and a number of surviving older larvae, particularly at southern locations. Assuming recessive resistance, the estimated resistance allele frequencies for Vip3Aa ranged from 0.115 in the Gulf states to 0.032 at more northern locations. These findings indicate that better resistance management practices are urgently needed to sustain efficacy the of corn and cotton that produce Vip3Aa.
Collapse
Affiliation(s)
- Galen P Dively
- Department of Entomology, University of Maryland, College Park, MD 20742, USA
| | - Tom P Kuhar
- Department of Entomology, Virginia Tech, Blacksburg, VA 24060, USA
| | - Sally V Taylor
- Department of Entomology, Virginia Tech, Suffolk, VA 23434, USA
| | | | - Kristian Holmstrom
- Pest Management Office, Rutgers University, New Brunswick, NJ 08901, USA
| | | | - Brian A Nault
- Department of Entomology, Cornell AgriTech, Geneva, NY 14456, USA
| | - Joseph Ingerson-Mahar
- Rutgers Agricultural Research and Extension Center, Rutgers University, Bridgeton, NJ 08302, USA
| | - Anders Huseth
- Department of Entomology and Plant Pathology, NC State University, Raleigh, NC 27601, USA
| | - Dominic Reisig
- Department of Entomology and Plant Pathology, NC State University, Plymouth, NC 27962, USA
| | - Shelby Fleischer
- Department of Entomology, Penn State University, University Park, PA 16802, USA
| | - David Owens
- Cooperative Extension, Carvel REC, University of Delaware, Georgetown, DE 19947, USA
| | - Kelley Tilmon
- Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA
| | - Francis Reay-Jones
- Department of Plant and Environmental Sciences, Clemson University, Florence, SC 29501, USA
| | - Pat Porter
- Department of Entomology, AgriLife Research and Extension Center, Texas A&M University, Lubbock, TX 79401, USA
| | - Jocelyn Smith
- Department of Plant Agriculture, University of Guelph, Ridgetown Campus, ON N1G 2W1, Canada
| | - Julien Saguez
- CEROM, 740 Chemin Trudeau, Saint-Mathieu-de-Beloeil, QC J3G 0E2, Canada
| | - Jason Wells
- New Brunswick Department of Agriculture, Sussex, NB E4E 5L8, Canada
| | - Caitlin Congdon
- Perennia Food and Agriculture, Kentville, NS B4N 1J5, Canada
| | - Holly Byker
- Department of Plant Agriculture, University of Guelph, Winchester, ON N1G 2W1, Canada
| | - Bryan Jensen
- Arlington Agricultural Research Station, University of Wisconsin, WI 53706, USA
| | - Chris DiFonzo
- Department of Entomology, Michigan State University, East Lansing, MI 48824, USA
| | | | - Eric Burkness
- Department of Entomology, University of Minnesota, St. Paul, MN 55455, USA
| | - Robert Wright
- Department of Entomology, University of Nebraska-Lincoln, NE 68588, USA
| | - Michael Crossley
- Department of Entomology and Wildlife Ecology, University of Delaware, Newark, DE 19711, USA
| | - Heather Darby
- Department of Plant and Soil Sciences, University of Vermont, Burlington, VT 05405, USA
| | - Tom Bilbo
- Department of Plant and Environmental Sciences, Clemson University, Charleston, SC 29414, USA
| | - Nicholas Seiter
- Illinois Extension, University of Illinois, Urbana, IL 61820, USA
| | - Christian Krupke
- Department of Entomology, Purdue University, West Lafayette, IN 47906, USA
| | - Craig Abel
- USDA-ARS Corn Insects and Crop Genetics Research, Iowa State University, Ames, IA 50011, USA
| | - Brad S Coates
- USDA-ARS Corn Insects and Crop Genetics Research, Iowa State University, Ames, IA 50011, USA
| | | | | | - Jeffrey Bradshaw
- Panhandle Research and Extension Center, Scottsbluff, NE 69361, USA
| | - Julie A Peterson
- West Central Research and Extension Center, University of Nebraska, North Platte, NE 69101, USA
| | - David Buntin
- Griffin Campus, University of Georgia, Griffin, GA 30223, USA
| | | | - Katelyn Kesheimer
- Department of Entomology & Plant Pathology, Auburn University, Auburn, AL 36849, USA
| | - Whitney Crow
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Delta Research and Extension Center, Mississippi State University, Stoneville, MS 39762, USA
| | - Jeffrey Gore
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Delta Research and Extension Center, Mississippi State University, Stoneville, MS 39762, USA
| | - Fangneng Huang
- Department of Entomology, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Dalton C Ludwick
- Department of Entomology, Texas A&M AgriLife Extension Service, Corpus Christi, TX 78404, USA
| | - Amy Raudenbush
- Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA
| | - Sebastian Jimenez
- PEI Department of Agriculture and Land, Charlotte, PE C1A 7N8, Canada
| | - Yves Carrière
- Department of Entomology, University of Arizona, Tucson, AZ 85721, USA
| | - Timothy Elkner
- Southeast Research and Extension Center, Landisville, PA 17538, USA
| | - Kelly Hamby
- Department of Entomology, University of Maryland, College Park, MD 20742, USA
| |
Collapse
|
14
|
Guan F, Dai X, Hou B, Wu S, Yang Y, Lu Y, Wu K, Tabashnik BE, Wu Y. Refuges of conventional host plants counter dominant resistance of cotton bollworm to transgenic Bt cotton. iScience 2023; 26:106768. [PMID: 37216101 PMCID: PMC10196555 DOI: 10.1016/j.isci.2023.106768] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/08/2023] [Accepted: 04/24/2023] [Indexed: 05/24/2023] Open
Abstract
Transgenic crops have revolutionized insect pest control, but evolution of resistance by pests threatens their continued success. The primary strategy for combating pest resistance to crops producing insecticidal proteins from Bacillus thuringiensis (Bt) uses refuges of non-Bt host plants to allow survival of susceptible insects. The prevailing paradigm is that refuges delay resistance that is rare and recessively inherited. However, we discovered refuges countered resistance to Bt cotton that was neither rare nor recessive. In a 15-year field study of the cotton bollworm, the frequency of a mutation conferring dominant resistance to Bt cotton surged 100-fold from 2006 to 2016 yet did not rise from 2016 to 2020. Computer simulations indicate the increased refuge percentage from 2016 to 2020 is sufficient to explain the observed halt in the evolution of resistance. The results also demonstrate the efficacy of a Bt crop can be sustained by non-Bt refuges of other crops.
Collapse
Affiliation(s)
- Fang Guan
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Xiaoguang Dai
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Bofeng Hou
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Shuwen Wu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Yihua Yang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Yanhui Lu
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Kongming Wu
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | | | - Yidong Wu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| |
Collapse
|
15
|
Tabashnik BE, Fabrick JA, Carrière Y. Global Patterns of Insect Resistance to Transgenic Bt Crops: The First 25 Years. JOURNAL OF ECONOMIC ENTOMOLOGY 2023; 116:297-309. [PMID: 36610076 DOI: 10.1093/jee/toac183] [Citation(s) in RCA: 40] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Indexed: 05/29/2023]
Abstract
Crops genetically engineered to produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) have improved pest management and reduced reliance on insecticide sprays. However, evolution of practical resistance by some pests has reduced the efficacy of Bt crops. We analyzed global resistance monitoring data for 24 pest species based on the first 25 yr of cultivation of Bt crops including corn, cotton, soybean, and sugarcane. Each of the 73 cases examined represents the response of one pest species in one country to one Bt toxin produced by one or more Bt crops. The cases of practical resistance rose from 3 in 2005 to 26 in 2020. Practical resistance has been documented in some populations of 11 pest species (nine lepidopterans and two coleopterans), collectively affecting nine widely used crystalline (Cry) Bt toxins in seven countries. Conversely, 30 cases reflect no decrease in susceptibility to Bt crops in populations of 16 pest species in 10 countries. The remaining 17 cases provide early warnings of resistance, which entail genetically based decreases in susceptibility without evidence of reduced field efficacy. The early warnings involve four Cry toxins and the Bt vegetative insecticidal protein Vip3Aa. Factors expected to favor sustained susceptibility include abundant refuges of non-Bt host plants, recessive inheritance of resistance, low resistance allele frequency, fitness costs, incomplete resistance, and redundant killing by multi-toxin Bt crops. Also, sufficiently abundant refuges can overcome some unfavorable conditions for other factors. These insights may help to increase the sustainability of current and future transgenic insecticidal crops.
Collapse
Affiliation(s)
| | - Jeffrey A Fabrick
- USDA ARS, U. S. Arid Land Agricultural Research Center, Maricopa, AZ, USA
| | - Yves Carrière
- Department of Entomology, University of Arizona, Tucson, AZ, USA
| |
Collapse
|
16
|
Santiago-González JC, Kerns DL, Head GP, Yang F. A Modified F2 Screen for Estimating Cry1Ac and Cry2Ab Resistance Allele Frequencies in Helicoverpa zea (Lepidoptera: Noctuidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2023; 116:289-296. [PMID: 36610074 DOI: 10.1093/jee/toac181] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Indexed: 05/30/2023]
Abstract
Evaluating the frequency of resistance alleles is important for resistance management and sustainable use of transgenic crops that produce insecticidal proteins from Bacillus thuringiensis. Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) is a major crop pest in the United States that has evolved practical resistance to the crystalline (Cry) proteins in Bt corn and cotton. The standard F2 screen for estimating resistance allele frequency does not work well for H. zea because successful single-pair matings are rare. In this study, we developed and implemented a modified F2 screen for H. zea that generates F1 progeny by crossing three laboratory susceptible female moths with one feral male moth instead of single-pair crosses. During 2019-2020, we used this modified method to establish 192 F2 families from 623 matings between susceptible females and feral males from Arkansas, Louisiana, Mississippi, and Tennessee. From each F2 family, we screened 128 neonates against discriminating concentrations of Cry1Ac and Cry2Ab in diet overlay bioassays. Based on these discriminating concentration bioassays, families were considered positive for resistance if at least five larvae survived to second instar, including at least one to third instar. The percentage of positive families was 92.7% for Cry1Ac and 38.5% for Cry2Ab, which yields an estimated resistance allele frequency (with 95% confidence interval) of 0.722 (0.688-0.764) for Cry1Ac and 0.217 (0.179-0.261) for Cry2Ab. The modified F2 screen developed and implemented here may be useful for future resistance monitoring studies of H. zea and other pests.
Collapse
Affiliation(s)
| | - David L Kerns
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | | | - Fei Yang
- Department of Entomology, Texas A&M University, College Station, TX, USA
| |
Collapse
|
17
|
Reisig D, Buntin GD, Greene JK, Paula-Moraes SV, Reay-Jones F, Roberts P, Smith R, Taylor SV. Magnitude and Extent of Helicoverpa zea Resistance Levels to Cry1Ac and Cry2Ab2 across the Southeastern USA. INSECTS 2023; 14:262. [PMID: 36975947 PMCID: PMC10058025 DOI: 10.3390/insects14030262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/27/2023] [Accepted: 03/02/2023] [Indexed: 06/18/2023]
Abstract
After resistance is first detected, continued resistance monitoring can inform decisions on how to effectively manage resistant populations. We monitored for resistance to Cry1Ac (2018 and 2019) and Cry2Ab2 (2019) from southeastern USA populations of Helicoverpa zea. We collected larvae from various plant hosts, sib-mated the adults, and tested neonates using diet-overlay bioassays and compared them to susceptible populations for resistance estimates. We also compared LC50 values with larval survival, weight and larval inhibition at the highest dose tested using regression, and found that LC50 values were negatively correlated with survival for both proteins. Finally, we compared resistance rations between Cry1Ac and Cry2Ab2 during 2019. Some populations were resistant to Cry1Ac, and most were resistant to CryAb2; Cry1Ac resistance ratios were lower than Cry2Ab2 during 2019. Survival was positively correlated with larval weight inhibition for Cry2Ab. This contrasts with other studies in both the mid-southern and southeastern USA, where resistance to Cry1Ac, Cry1A.105, and Cry2Ab2 increased over time and was found in a majority of populations. This indicates that cotton expressing Cry proteins in the southeastern USA was at variable risk for damage in this region.
Collapse
Affiliation(s)
- Dominic Reisig
- Department of Entomology, The Vernon James Center, North Carolina State University, Plymouth, NC 27962, USA
| | - G. David Buntin
- Department of Entomology, University of Georgia, Tifton, GA 31793, USA
| | - Jeremy K. Greene
- Department of Plant and Environmental Sciences, Clemson University, Blackville, SC 29817, USA
| | | | - Francis Reay-Jones
- Department of Plant and Environmental Sciences, Clemson University, Blackville, SC 29817, USA
| | - Phillip Roberts
- Department of Entomology, University of Georgia, Tifton, GA 31793, USA
| | - Ron Smith
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA
| | - Sally V. Taylor
- Department of Entomology, Virginia Polytechnic Institute and State University, Suffolk, VA 23437, USA
| |
Collapse
|
18
|
Santiago-González JC, Kerns DL, Yang F. Resistance Allele Frequency of Helicoverpa zea to Vip3Aa Bacillus thuringiensis Protein in the Southeastern U.S. INSECTS 2023; 14:161. [PMID: 36835730 PMCID: PMC9958976 DOI: 10.3390/insects14020161] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/23/2023] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
Helicoverpa zea is a major target pest of Bt crops expressing Cry and/or Vip3Aa proteins in the U.S.A. Widespread practical resistance of H. zea to the Cry1 and Cry2 proteins makes Vip3Aa the only effective Bt protein against this pest. Understanding the frequency of resistance alleles against Vip3Aa in field populations of H. zea is crucial for resistance management and the sustainability of Vip3Aa technology. Using a modified F2 screen method by crossing susceptible laboratory female moth with feral male moth of H. zea, we successfully screened a total of 24,576 neonates from 192 F2 families of H. zea collected from Arkansas, Louisiana, Mississippi, and Tennessee during 2019-2020. We found five F2 families containing ≥3rd instar survivors on the diagnostic concentration of 3.0 µg/cm2 Vip3Aa39. Dose-response bioassays confirmed the high levels of Vip3Aa resistance in these F2 families, with an estimated resistance ratio of >909.1-fold relative to the susceptible strain. The estimated resistance allele frequency against Vip3Aa in H. zea for these four southern states is 0.0155 with a 95% CI of 0.0057-0.0297. These data should provide critical information for understanding the risks of Vip3Aa resistance in H. zea and help design appropriate resistance management strategies for the sustainability of the Vip3Aa technology.
Collapse
|