Source: LEPIDEXT L.L.C submitted to
A METHOD TO SUPPRESS BT RESISTANCE IN THE CORN EARWORM
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
SMALL BUSINESS GRANT
Reporting Frequency
Annual
Accession No.
1025899
Grant No.
2021-33530-34511
Cumulative Award Amt.
$106,500.00
Proposal No.
2021-01577
Multistate No.
(N/A)
Project Start Date
Jul 1, 2021
Project End Date
Feb 28, 2023
Grant Year
2021
Program Code
[8.2]- Plant Production and Protection-Biology
Recipient Organization
LEPIDEXT L.L.C
1122 OAK HILL DR
LEXINGTON,KY 40505
Performing Department
(N/A)
Non Technical Summary
Among the persisent and long terms threats to US agriculture the matter of resistance development in pest such as insects, weeds and pathogens ranks high. There are many examples of pesticides that were once effective that have now completely lost their utility. While any pesticide that is widely and repeatedly used places a very strong selection pressure on a pest population to evolve methods to evade, detoxify or otherwise escape pesticide pressure, polyphagous insects such as the corn earworm, Helicoverpa zea, have been notable for their propensity to develop resistance. Entire classes of insecticides can no longer be used to control this pest. Perhaps the most worrisome is the relatively rapid development of resistance of this insect to the Bt toxins expressed in transgenic plants. Because these toxins are delivered via plant expression, H. zea and other susceptible insect pests are persistently exposed to literally millions of acres of toxin across the US and the globe. Those insects that have genetic resistance and can survive exposure to the toxin have a marked evolutionary advantage that drives rapid spread of resistance within pest populations. While refugia requirements have helped to slow the spread of resistance it is increasingly clear that new methods to combat insect resistance are desperately needed. Lepidext has identified one such agent with potential to not only actively suppress populations of Bt resistant pest insects and seeks support through this proposal to further develop this technology and approach.
Animal Health Component
50%
Research Effort Categories
Basic
25%
Applied
50%
Developmental
25%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2113110110140%
1331480113040%
2151719110110%
2164030110110%
Knowledge Area
211 - Insects, Mites, and Other Arthropods Affecting Plants; 133 - Pollution Prevention and Mitigation; 215 - Biological Control of Pests Affecting Plants; 216 - Integrated Pest Management Systems;

Subject Of Investigation
1480 - Sweetcorn; 1719 - Cotton, other; 3110 - Insects; 4030 - Viruses;

Field Of Science
1101 - Virology; 1130 - Entomology and acarology;
Goals / Objectives
The primary goals of this project are to: 1) evaluate the effects of a strain of the Helicoverpa zea nudivirus on the incidence of Bt resistance on a mixed population of resistant and susceptible insects that are feeding on either diet that contains a Bt toxin or diet that lacks a toxin. This laboratory experiment is designed to mimic conditions in the field where Bt resistance is developing. 2) the second objective is to take the results of this laboratory experiment and integrate those results into a population model for resistance development. A preliminary version of this model has been developed and the data from the primary goal will be used to inform and develop this model. Taken together the results will test and demonstrate whether or not this hypervirulelent, sterilizing virus can be developed into a new tool and approach for managing Bt resistance in transgenic crops.
Project Methods
This project relies upon established methods for insect rearing, virus production, quantifiactionand mathematical modelling. In prior work a viral strain was selected that causeshigher sterility than wild-type HzNV-2. Optimal dosing and timing for production of sterile insect progeny were established and will be used in this project. The Bt toxin will be produced in E. coli and expressed from a recombinant plasmid, partially purified and added to insect diet. The Bt-resistant corn earworm lines were produced in the laboratory and will be made available for this project by the Carrier lab at the University of Arizona.

Progress 07/01/21 to 10/27/22

Outputs
Target Audience:This project has several target audiences. First, farmers of Bt-expressing crops, notably corn and cotton, are a major target for this product. These farmers are experiencing the resistance development in the corn earworm and the high cost of newer Bt traits. We have interacted directly with this audience at AgLaunch Field days in the summer of 2021 and 2022. Several farmers are also investors in Lepidext. Lepidext has also been in communication with the agrichemical companies that have developed Bt traits. There are varied responses to our new technology which Lepidext believes can extend the utility of Bt traits. Lepidext is also in regular communication with both actual and prospective investors regarding this technology individually and through investor forums. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project supported four undergraduate students. One of the undergraduate students joined our lab upon completion of her degree from the Agricultural and Medical Biotechnolgy program at the University of Kentucky. How have the results been disseminated to communities of interest?Lepidext participated at AgLaunch Field Day 2021 and 2022 in Savannah, TN. A video of Dr. Webb's presentation is available on-line on YouTube (https://www.youtube.com/watch?v=6FrkECRE3fI). What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Two experiments showed that Bt-resistant and susceptible insects were equally susceptible to the effects of InsterusHz. Susceptible insects, as expected, showed higher mortality when fed Bt diets than resistant insects and Bt resistant insects were developmentally delayed when fed upon Bt diets as has been reported in the literature. A population model was developed that indicated that it would be possible to target Bt resistant insects by taking advantage of the developmental delays caused by exposure to Bt. This was proposed in a Phase 2 submission which was not funded.

Publications


    Progress 07/01/21 to 06/30/22

    Outputs
    Target Audience:This project has several target audiences. First, farmers of Bt-expressing crops, notably corn and cotton, are a major target for this product. These farmers are experiencing the resistance development in the corn earworm and the high cost of newer Bt traits. We have interacted directly with this audience at AgLaunch Field days in the summer of 2021 and 2022. Several farmers are also investors in Lepidext. Lepidext has also been in communication with the agrichemical companies that have developed Bt traits. There are varied responses to our new technology which Lepidext believes can extend the utility of Bt traits. Lepidext is also in regular communication with both actual and prospective investors regarding this technology individually and through investor forums. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project supported four undergraduate students. One of the undergraduate students joined our lab upon completion of her degree from the Agricultural and Medical Biotechnolgy program at the University of Kentucky. How have the results been disseminated to communities of interest?Lepidext participated at AgLaunch Field Day 2021 and 2022 in Savannah, TN. A video of Dr. Webb's presentation is available on-line on YouTube (https://www.youtube.com/watch?v=6FrkECRE3fI). What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

    Impacts
    What was accomplished under these goals? Two experiments showed that Bt-resistant and susceptible insects were equally susceptible to the effects of InsterusHz. Susceptible insects, as expected, showed higher mortality when fed Bt diets than resistant insects and Bt resistant insects were developmentally delayed when fed upon Bt diets as has been reported in the literature. A population model was developed that indicated that it would be possible to target Bt resistant insects by taking advantage of the developmental delays caused by exposure to Bt. This was proposed in a Phase 2 submission which was not funded.

    Publications