Poster: Plant Insect/Nematode Interactions

Abs # 687: Identification of novel genes regulated by silverleaf whitefly (Bemisia argentifolii) feeding

Presenter:	Zarate, Sonia I, sonia@mail.ucr.edu
Authors	Zarate, Sonia I (A)   van de Ven, Wilhelmina  (A)   Puthoff, David  (B)   Patricia, Springer S (A)   Linda, Walling L (A)
Affiliations:	(A): UC Riverside, Department of Botany and Plant Sciences (B): Iowa State University, Department of Plant Pathology

The area of research focused on plant-insect interactions is at its inception. We have studied plant interactions with phloem-feeding silverleaf whitefly (Bemisia argentifolii), which inflicts little tissue damage to its host plants. Our studies examining tomato pathogenesis-related protein gene expression indicates that whiteflies induce the defense pathways activated by bacteria, fungi, and viral pathogens. In addition, we have identified novel genes from tomato and squash using differential RNA display. These genes are up-regulated by whitefly feeding and encode a whitefly-induced NADPH oxidase subunit (Wfi1) M20b peptidase-like protein (SLW1), and a b-glucosidase-like protein (SLW3) Wfi1 and SLW1 RNAs accumulate after jasmonic acid and ethylene treatments, while SLW3 is not responsive to any known defense signals. Wfi1 RNAs accumulate locally and systemically in tomato after nymphal feeding but not in response to pink potato aphid or adult whiteflies. Similarly, SLW1 and SLW3 transcripts accumulate systemically in squash leaves after silverleaf whitefly nymph feeding but not after feeding by silverleaf whitefly adults or sweet potato whitefly nymphs (Bemisia tabaci Type A). These studies indicate that plant responses to whiteflies can be whitefly species-specific, nymph-specific and differ locally and systemically. While our studies have demonstrated the complexity and dynamic interactions between tomatoes and squash with this phloem-feeding insect, these crop plants lack the powerful tools of genetics afforded by the plant model system Arabidopsis thaliana. Experiments exploiting the powerful genomic tool, the “gene/enhancer trap” are currently being conducted in an effort to identify novel genes activated and suppressed by silverleaf whitefly feeding.