Chi-Wei's webpage

Leafroll virus-vector interaction

This is an ongoing project. We are interested in determining where is the retention site of leafroll viruses in insects, what viral protein(s) bind to insect mouthparts or foregut, what viral protein(s) may serve as helper component(s), and the effect of multiple infections within the plant on mealybug transmission.

My research interests focus on insect vector-virus-host plant interactions. I use a variety of molecular techniques to investigate this interdisciplinary subject. My current projects include the study of interactions among mealybug vectors, grapevine leafroll viruses and grape hosts. Below is a brief description of some of my current and previous projects.
Transmission biology of leafroll viruses Grapevine leafroll disease occurs in all the major grape-growing areas worldwide, and the disease adversely impacts both vine health and grape quality. Mealybug transmission seem to be the only means of natural spread of this disease. I am studying how transmission occurs, what factors affect transmission efficiency, and what are the implications of mealybug-virus-grapevine interactions on disease spread .
Transmission of GLRaV-3 by the vine mealybug Grapevine leafroll disease is caused by grapevine leafroll associated viruses (GLRaVs). Within this virus complex, GLRaV-3 is the most predominant species in the world. We have characterized the transmission parameters of GLRaV-3 by the vine mealybug. Our results suggest that the vine mealybug transmits GLRaV-3 in a semi-persistent manner. Virus transmission occurred within few hours of virus acquisition, and transmission efficiency increased with longer plant access time. In addition, vine mealybugs transmitted GLRaV-3 with a short latent period. Vine mealybugs lost acquired viruses and infectivity four days post-acquisition feeding.
Leafroll virus-vector interaction This is an ongoing project. We are interested in determining where is the retention site of leafroll viruses in insects, what viral protein(s) bind to insect mouthparts or foregut, what viral protein(s) may serve as helper component(s), and the effect of multiple infections within the plant on mealybug transmission.
Functional genomics of rhabdoviruses This was part of my PhD studies. Many rhabdoviruses are economically important pathogens of humans, livestock, and crops, of which Rabies virus is the most well known species. I was interested in insect-borne plant rhabdoviruses because they are able to infect and replicate in two divergent hosts: plants and insects. We sequenced and analyzed the genome of two plant rhabdoviruses, Maize fine streak virus (MFSV) and Maize mosaic virus (MMV). Subcellular localization study showed that the MFSV N, ORF4, and ORF5 proteins accumulated in the nucleus of plant and insect cells. We further explored the mechanism of nuclear import of viral proteins by RNA interference (RNAi).
Rhabdovirus-host interaction This was also part of my PhD studies. Sigma rhabdovirus (SigV) is a naturally occurring infection in Drosophila spp. and is maintained in fly populations through vertical transmission via germ cells. We have investigated the molecular response of Drosophila against SigV infection by microarray and quantitative real-time RT-PCR. Specifically, SigV infection upregulated the expression of peptidoglycan receptor genes and a number of anti-microbial peptide genes controlled by immune deficiency (Imd) pathway. We compared our results with the immune response of Drosophila to other viruses and suggested that Drosophila immune system has ability to recognize different types of viruses.