Submitted to: American Society of Plant Biologists
Publication Type: Abstract Only
Publication Acceptance Date: March 12, 2009
Publication Date: March 21, 2009
Citation: Dowd, P.F., Johnson, E.T. 2009. Bioenergy Promise Versus a Bug: How Different Cultivars of Switchgrass Fare Against the Fall Armyworm (Spodoptera frugiperda) [abstract]. American Society of Plant Biologists. Abstract No. 21. Technical Abstract: Switchgrass (Panicum virgatum L.) is a North American native plant that is being considered for bioenergy production. A number of different commercial cultivars were evaluated for resistance to the fall armyworm. Differential feeding resistance was detected among the cultivars, but no insect mortality was found. Resistance levels of some field-collected leaves were comparable to the cultivars while other wild leaves caused armyworm mortality. Assays of possible insect-resistance enzymes found that there were expression differences among the cultivars for two peroxidases but not in two chitin-degrading enzymes. Sequencing of portions of expressed insect-resistance genes revealed a range of nucleotide polymorphisms. A segment of cationic peroxidase displayed a large number of nucleotide substitutions that resulted in changes at the amino acid level. Our data indicate that variability in armyworm resistance among switchgrass cultivars could potentially be due to genetic polymorphism of vital insect resistance genes.