March 6, 2013
Whitfield will be introduced by her former major professor, entomologist Diane Ullman, associate dean for undergraduate academic programs in the College of Agricultural and Environmental Sciences and a professor and former chair of the UC Davis Department of Entomology.
Whitfield received her master's degree in plant pathology from Ullman in 1999 and her doctorate in plant pathology from the University of Wisconsin, Madison, in 2004.
"Arthropod vectors play an essential role in dissemination of viruses that cause diseases in humans, animals, and plants," Whitfield says. "More than 70 percent of viruses infecting plants and 40 percent of viruses infecting mammals are transmitted from one host to another by arthropod vectors. My research is devoted to investigating plant-virus-vector interactions at the molecular level with the goal of developing a better understanding of the complex sequence of events leading to virus acquisition and transmission by vectors."
"Tomato spotted wilt virus (TSWV) is considered one of the ten most devastating plant viruses and is one of the viruses that we are working with to define the viral and vector determinants of transmission. The virus is transmitted by thrips (Thysanoptera: Thripidae), primarily Frankliniella occidentalis. The TSWV glycoproteins, designated GN and GC, are required for infection of thrips. We found that recombinant GN (GN-S) bound larval thrips midguts in a specific manner and inhibited TSWV acquisition and transmission (Whitfield et al., 2004, and Whitfield et al., 2008)."
"Our findings," Whitfield said, "provide evidence that GN serves as a viral ligand that mediates attachment of TSWV to receptors displayed on the epithelial cells of the thrips midgut. We generated transgenic tomato plants expressing a soluble form of GN with a GFP tag (GN-S::GFP) and found that thrips that fed on these transgenics had significantly lower virus titers and adult transmission efficiencies than thrips fed on TSWV-infected non-transgenic tomato plants. These results demonstrate that an initial reduction in virus infection of the larval insect midgut can result in a significant decrease in virus titer and transmission over the life-span of the vector. Despite the world-wide importance of thrips in agriculture, there is little knowledge of the F. occidentalis genome or gene functions at this time. We developed the first transcriptome analysis of F. occidentalis, and the partial thrips transcriptome was used to characterize the thrips proteome and response to virus infection (Rotenberg and Whitfield, 2010, Badillo-Vargas et al., 2012). Knowledge of thrips recognition and response to virus infection will enable us to develop new strategies to disrupt virus transmission."
Whitfield is the author of numerous publications and book chapters. She has published her work in the Journal of Virological Methods, Insect Molecular Biology, Journal of Virology and the Journal of Economic Entomology, among others.
--Kathy Keatley Garvey
Communications specialist
UC Davis Department of Entomology
(530) 754-6894