Yuan, Joshua S. , Wiggins, Greg , Grant, Jerome , Chen, Feng .
Metabolic, Genomic and Biochemical Analyses Identify Novel Genes Involved in Attracting Natural Enemies of Rice Herbivores.
Plants attacked by herbivorous insects emit complex mixtures of volatiles that attract the herbivore’s natural enemies. This so-called indirect defense has been relatively well studied at the ecological level. In contrast, our understanding of molecular mechanisms responsible for production of herbivore-induced plant volatiles is still limited. We employ an integrated genomics approach to study molecular basis of indirect defense in rice (Oryza sativa). Metabolic profiling showed that, when damaged by fall armyworm (Spodeptera frugiperda, FAW), rice seedlings emit a host of volatile compounds with terpenoids the most predominant. Olfactometer bioassays showed that FAW-induced rice volatiles preferentially attract parasitic wasps (Cotesia marginiventris). To identify genes for synthesizing FAW-induced rice volatiles, we performed microarray experiments. A large number of candidate volatile-producing genes were identified. We then focused on characterizing genes for producing volatile terpenoids using biochemical assays. Two rice terpene synthase genes were determined to encode sesquiterpene synthases responsible for the biosynthesis of complex mixture of volatile sesquiterpenes induced by FAW. Another rice terpene synthase gene was determined to encode a monoterpene synthase, whose product linalool is the most abundant among FAW-induced rice volatiles. Further olfactometer bioassays demonstrated that linalool has a role in attracting C. marginiventris. Identification of these volatile-producing genes in rice provides opportunities for exploring the contribution of individual volatiles to the attractiveness of FAW-damaged rice plants to C. marginiventris.
Log in to add this item to your schedule
1 - University of Tennessee, Plant Sciences
2 - University of Tennessee, Entomology and Plant Pathology
3 - University of Tennessee, Plant Sciences, 252 Ellington Plant Science Building, 2431 Joe Johnson Drive, Knoxville, TN, 37996, USA
Indirect defense against insects
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM