Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 8, 2013
Publication Date: N/A
Interpretive Summary: Cotton tissue from lines that are being developed for abiotic stress through transgenic techniques were fed to beet armyworms to determine their effect on growth and development factors such as egg hatch, larval weights, and ability to pupate on the beet armyworm. The inherent trait that would have a negative impact on the growth and development are proteins that cause either mortality or slow growth and development because of a germin-like protien that is a result of the breeding for abiotic stress. Three of the transgenic lines given the names ABP-A, ABP-B, and ABP-C showed a negative and significant impact on larval growth and development when compare to the parent line Coker 312 and ABP-D. Egg hatch was similar for all five entries in the feeding bioassay. However, larval live-weights, and ability to pupate were the factors that were affected by the presence of the germin-like protein. In summary, these feeding bioassays show the potential for using cotton germin-like protein to improve resistance or tolerance for beet armyworms attacking cotton.
Technical Abstract: Transgenic cotton lines that ectopically express a cotton germin-like protein (ABP) were screened for resistance/tolerance factors to the beet armyworm (BAW) Spodoptera exigua (Hubner) via feeding assays. The number of BAW eggs that successfully hatched was not statistically different at 72 h observation for wild-type cotton plants (Gossypium hirsutum L. c.v. Coker 312) or plants of four independent transgenic lines (ABP-A, ABP-B, ABP-C, and ABP-D). However, the damage caused by these same larvae at 72 h was higher for the Coker 312 and line ABP-D when compared to ABP-A, ABP-B, and ABP-C transgenic plants. Larval live weights were also significantly higher for Coker 312 and ABP-D at 5, 7, and 14 d when compared to ABP-A, ABP-B, and ABP-C. Finally, the percentage of larvae that successfully completed pupation was significantly higher for BAW larvae fed Coker 312 and ABP-D tissue compared to the other three lines. In summary, these feeding bioassays show the potential for using cotton germin-like protein to improve resistance or tolerance for beet armyworms attacking cotton.