Borrow it
Coverart for item
The Resource Inheritance, fitness costs, and potential mechanisms of resistance for western corn rootwork larvae surviving Bt corn, by Ryan W. Geisert

Inheritance, fitness costs, and potential mechanisms of resistance for western corn rootwork larvae surviving Bt corn, by Ryan W. Geisert

Creator
Author
Contributor
Summary
The western corn rootworm, Diabrotica virgifera virgifera LeConte, has developed resistance to most control tactics used to manage it. Transgenic corn varieties that express insecticidal proteins from the bacterium Bacillus thuringiensis Berliner (Bt), cause mortality to target pests when ingested. In an attempt to delay resistance formation to these Bt products, the Environmental Protection Agency mandates the development of an insect resistance management program prior to registration for commercial sale. Despite plans to delay resistance being in place, resistance has developed in the field for both Cry3Bb1 and mCry3A-expressing hybrids. Resistance to these products could be due to physiological adaptations or through behavioral avoidance of the toxin in the plant. For the first portion of this work, we investigated a behavioral avoidance hypothesis for resistance. We hypothesized that later hatching western corn rootworm larvae could utilize previous feeding damage on Bt corn roots by early hatching larvae as an entry point into the root cortex containing lower levels of the Bt protein. Field and greenhouse tests involving infestation staggering to facilitate previous feeding damage did not support our hypothesis and did not indicate any effect of previous root feeding on the ability of this pest to establish on Bt plants and cause damage. We also evaluated resistance dynamics in the western corn rootworm in response to the most recent Bt protein commercialized for rootworm management, eCry3.1Ab. For one experiment, an eCry3.1Ab-selected and a paired control western corn rootworm colony were utilized to determine the potential fitness costs associated with eCry3.1Ab resistance. Adult longevity, egg viability, and larval development time results indicated a lack of fitness costs associated with eCry3.1Ab resistance in the western corn rootworm. Reciprocally crossed colonies of the eCry3.1Ab-selected and control colonies were created in order to evaluate whether the resistance trait to eCry3.1Ab was recessive, dominant, or something in between. Each reciprocal cross and their parent colonies were evaluated in diet toxicity and plant assays. Results indicated that the eCry3.1Ab resistance trait we selected for under laboratory conditions is dominantly inherited
Language
eng
Work
Publication
Extent
1 online resource (ix, 102 pages)
Note
  • "A Dissertation presented to the Faculty of the Graduate School at the University of Missouri In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy."
  • Dissertation supervisor: Dr. Bruce E. Hibbard
  • Includes vita
Instance
Label
Inheritance, fitness costs, and potential mechanisms of resistance for western corn rootwork larvae surviving Bt corn
Title
Inheritance, fitness costs, and potential mechanisms of resistance for western corn rootwork larvae surviving Bt corn
Statement of responsibility
by Ryan W. Geisert
Title variation
Inheritance, fitness costs, and potential mechanisms of resistance for western corn rootwork larvae surviving Bacillus thuringiensis Berliner corn
Creator
Contributor
Author
Thesis advisor
Subject
Genre
Language
eng
Summary
The western corn rootworm, Diabrotica virgifera virgifera LeConte, has developed resistance to most control tactics used to manage it. Transgenic corn varieties that express insecticidal proteins from the bacterium Bacillus thuringiensis Berliner (Bt), cause mortality to target pests when ingested. In an attempt to delay resistance formation to these Bt products, the Environmental Protection Agency mandates the development of an insect resistance management program prior to registration for commercial sale. Despite plans to delay resistance being in place, resistance has developed in the field for both Cry3Bb1 and mCry3A-expressing hybrids. Resistance to these products could be due to physiological adaptations or through behavioral avoidance of the toxin in the plant. For the first portion of this work, we investigated a behavioral avoidance hypothesis for resistance. We hypothesized that later hatching western corn rootworm larvae could utilize previous feeding damage on Bt corn roots by early hatching larvae as an entry point into the root cortex containing lower levels of the Bt protein. Field and greenhouse tests involving infestation staggering to facilitate previous feeding damage did not support our hypothesis and did not indicate any effect of previous root feeding on the ability of this pest to establish on Bt plants and cause damage. We also evaluated resistance dynamics in the western corn rootworm in response to the most recent Bt protein commercialized for rootworm management, eCry3.1Ab. For one experiment, an eCry3.1Ab-selected and a paired control western corn rootworm colony were utilized to determine the potential fitness costs associated with eCry3.1Ab resistance. Adult longevity, egg viability, and larval development time results indicated a lack of fitness costs associated with eCry3.1Ab resistance in the western corn rootworm. Reciprocally crossed colonies of the eCry3.1Ab-selected and control colonies were created in order to evaluate whether the resistance trait to eCry3.1Ab was recessive, dominant, or something in between. Each reciprocal cross and their parent colonies were evaluated in diet toxicity and plant assays. Results indicated that the eCry3.1Ab resistance trait we selected for under laboratory conditions is dominantly inherited
Cataloging source
MUU
http://library.link/vocab/creatorName
Geisert, Ryan W
Degree
PhD
Dissertation note
Thesis
Dissertation year
2015.
Government publication
government publication of a state province territory dependency etc
Granting institution
University of Missouri--Columbia
Illustrations
illustrations
Index
no index present
Literary form
non fiction
Nature of contents
  • dictionaries
  • bibliography
  • theses
http://library.link/vocab/relatedWorkOrContributorName
Hibbard, Bruce E.
http://library.link/vocab/subjectName
  • Western corn rootworm
  • Bacillus thuringiensis
  • Corn
  • Pests
  • Heredity
Label
Inheritance, fitness costs, and potential mechanisms of resistance for western corn rootwork larvae surviving Bt corn, by Ryan W. Geisert
Instantiates
Publication
Note
  • "A Dissertation presented to the Faculty of the Graduate School at the University of Missouri In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy."
  • Dissertation supervisor: Dr. Bruce E. Hibbard
  • Includes vita
Bibliography note
Includes bibliographical references
Carrier category
online resource
Carrier category code
  • cr
Carrier MARC source
rdacarrier
Content category
text
Content type code
  • txt
Content type MARC source
rdacontent
Control code
958934337
Extent
1 online resource (ix, 102 pages)
Form of item
online
Media category
computer
Media MARC source
rdamedia
Media type code
  • c
Other physical details
illustrations
Specific material designation
remote
System control number
(OCoLC)958934337
Label
Inheritance, fitness costs, and potential mechanisms of resistance for western corn rootwork larvae surviving Bt corn, by Ryan W. Geisert
Publication
Note
  • "A Dissertation presented to the Faculty of the Graduate School at the University of Missouri In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy."
  • Dissertation supervisor: Dr. Bruce E. Hibbard
  • Includes vita
Bibliography note
Includes bibliographical references
Carrier category
online resource
Carrier category code
  • cr
Carrier MARC source
rdacarrier
Content category
text
Content type code
  • txt
Content type MARC source
rdacontent
Control code
958934337
Extent
1 online resource (ix, 102 pages)
Form of item
online
Media category
computer
Media MARC source
rdamedia
Media type code
  • c
Other physical details
illustrations
Specific material designation
remote
System control number
(OCoLC)958934337

Subject

Genre

Library Locations

  • St. Louis Mercantile LibraryBorrow it
    1 University Blvd, St. Louis, MO, 63121, US
    38.710138 -90.311107
  • Thomas Jefferson LibraryBorrow it
    1 University Blvd, St. Louis, MO, 63121, US
    38.710138 -90.311107
  • University ArchivesBorrow it
    703 Lewis Hall, Columbia, MO, 65211, US
  • University of Missouri-St. Louis Libraries DepositoryBorrow it
    2908 Lemone Blvd, Columbia, MO, 65201, US
    38.919360 -92.291620
  • University of Missouri-St. Louis Libraries DepositoryBorrow it
    2908 Lemone Blvd, Columbia, MO, 65201, US
    38.919360 -92.291620
  • Ward E Barnes Education LibraryBorrow it
    8001 Natural Bridge Rd, St. Louis, MO, 63121, US
    38.707079 -90.311355

Library Links

Structured data from the Bibframe namespace is licensed under the Creative Commons Attribution 4.0 International License by University of Missouri-St. Louis Libraries. Additional terms may apply to data associated with third party namespaces.
Processing Feedback ...