BIOLOGICALLY-BASED TECHNOLOGIES FOR MANAGEMENT OF CROP INSECT PESTS IN LOCAL AND AREA-WIDE PROGRAMS
Location: Insect Behavior and Biocontrol Research Unit
Title: Expression of crylFa in bahiagrass enhances resistance to fall armyworm
| Luciani, Gabriela - UF, AGRONOMY DEPT |
| Altpeter, Fredy - UF, AGRONOMY DEPT |
| Yactayo-Chang, Jessica - UF, AGRONOMY DEPT |
| Zhang, Hangning - UF, AGRONOMY DEPT |
| Gallo, Maria - UF, AGRONOMY DEPT |
| Wofford, David - UF, AGRONOMY DEPT |
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 9, 2007
Publication Date: November 1, 2007
Citation: Luciani, G., Altpeter, F., Yactayo-Chang, J., Zhang, H., Gallo, M., Meagher Jr, R.L., Wofford, D. 2007. Expression of crylFa in bahiagrass resistance to fall armyworm. Crop Science. 47:2430-2436.
Interpretive Summary: Fall armyworm infests and can be a serious pest of forage and turf grasses in the southeastern United States. Scientists from the University of Florida and an entomologist at the Center for Medical, Agricultural and Veterinary Entomology (CMAVE), Gainesville, Florida, conducted laboratory experiments to enhance the resistance of bahiagrass cultivars to fall armyworm. Using biotechnology techniques, a gene from the bacterium Bacillus thuringiensis was inserted into ‘Tifton 9’ bahiagrass and tests showed that the grass was able to produce enough toxins to kill very young fall armyworm larvae. This is the first report on insect resistance in a transgenic turf and forage grass.
Bahiagrass (Paspalum notatum var. Flugge) is the predominant forage grass in Florida and in subtropical regions worldwide. To improve pest resistance against fall armyworm (Spodoptera frugiperda J. E. Smith), an optimized cry1Fa gene encoding a '-endotoxin from Bacillus thuringiensis was synthesized, subcloned under the transcriptional control of the constitutive ubi1 promoter, and introduced into the bahiagrass cultivar ‘Tifton 9’ by microparticle bombardment. Three transgenic bahiagrass lines were generated using minimal transgene expression cassettes without vector backbone. Southern blot analyses showed independent cry1Fa transgene integration patterns for the three lines. Transcripts of cry1Fa were detected in all three transgenic lines by RT-PCR. Cry1Fa protein was detected in two lines by immunochromatography and quantitative Cry1Fa ELISA. The Cry1Fa ELISA also indicated stable cry1Fa transgene expression in vegetative progeny plants of both lines. Cry1Fa expression levels correlated well to resistance levels determined by insect bioassays. An average mortality rate of 83 % was observed when neonate larvae of fall armyworm were fed with transgenic leaves of the highest cry1Fa expressing line. These results indicate that minimal expression cassette technology supports stable and high level expression of cry1Fa in bahiagrass which can control fall armyworm, a devastating pest of forage grasses.