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Jeanmarie Verchot-Lubicz
Oklahoma State University
Associate Professor, Entomology and Plant Pathology
Address: 127 Noble Research Center, OSU, Stillwater, OK 74078
Phone: 405-744-7895 Fax: 405-744-6039
Email: verchot.lubicz@okstate.edu
URL: http://www.ento.okstate.edu/profiles/verchot.html
Ph.D., Microbiology, 1996, Texas A&M University Lab Photo
Postdoctoral: Plant Virology 1996-99, Sainsbury Laboratory, Norwich UK
Research Emphasis: Potato virus X and Soilborne wheat mosaic virus, studies of virus intercellular transport mechanisms
Related Activities: Member OSU Wheat Improvement Team (WIT) and Great Plains Cereal Biotechnology Consortium (GPCBC)
 
Research Description:

My research focuses on studying the mechanisms regulating viral intercellular and vascular transport in plants. We use tools of cellular and molecular biology. Research in my laboratory focuses on two viruses:

POTATO VIRUS X (PVX)
Potato virus X requires four viral proteins to move through plasmodesmata. These proteins are TGBp1, which is an ATPase, and a suppressor of gene silencing; TGBp2 and TGBp3, which are both ER/Golgi associated proteins; and coat protein (CP). We recently determined that TGBp2 and TGbp3 are ER/Golgi associated but we do not know the role of the endomembrane system in viral plasmodesmata transport. We are working to characterize the requirements for Potato virus X cell-to-cell movement. PVX encodes four viral proteins that facilitate plasmodesmata transport. Our primary goal is to study protein-protein interactions required for virus plasmodesmata transport, and unloading in the adjacent cell. One PVX protein is a suppressor of gene silencing as well as a factor required for virus movement. We are beginning to study how viral movement and gene silencing correlate.

The tools we use include biolistic bombardment, epifluorescence and confocal microscopy, and reverse genetics. We have prepared plasmids containing the PVX genes fused to GFP and introduced these into tobacco leaf epidermal cells by biolistic bombardment. Epifluorescence microscopy is used to follow protein cell-to-cell movement. We have prepared transgenic tobacco plants expressing each of the viral proteins and these plants are being used for our biolistic bombardment studies. The transgenic plants have been important tools for studying protein-protein interactions and protein subcellular targeting. We also are using mutational analysis to study protein-protein interactions and the requirements for virus movement.

We determined that two PVX proteins associate with the ER and Golgi and we are working to determine how this relates to virus movement. We do not know if these proteins use the ER/Golgi on their path toward degradation or if they require these systems to move through the plasmodesmata. Future work will be conducted to explore the role of the endomembrane system in virus transport.

SOILBORNE WHEAT MOSAIC VIRUS (SBWMV)
One goal of my research program is to study the requirements for SBWMV cell-to-cell and vascular transport in plants. SBWMV causes stunting and severe yield losses in hard red winter wheat in the central Great Plains of the USA. There is little known about the biology of the virus. We are using cell biology techniques to track virus movement in plants. Currently we have found that SBWMV may utilize the xylem for long distance transport. This is unusual because most viruses move through the phloem. We are currently working to determine if SBWMV utilizes only the xylem or both xylem and phloem transport to reach different regions of the plant.

Second, we are interested in the mechanisms that confer resistance to SBWMV. We have used a systematic approach to determine that there are separable traits that can be observed in resistant plants. Two traits relate to plant height and fungal transmission of the virus. We are currently developing inbred lines to map resistance genes.

Fourth we are working to prepare transgenic wheat expressing SBWMV proteins that may be resistant to SBWMV. We will work to characterize the mechanisms of resistance. We also anticipate some transgenic lines will not be resistant to SBWMV and may express the viral proteins. We will use these lines to analyze viral protein functions. We will use these lines for complementation of mutant viruses.
 
Recent Publications:

Ju HJ, Samuels TD, Ye CM, Verchot-Lubicz J (2007) A central conserved amino acid sequence of PVX TGBp2 is necessary for vesicle formation and virus movement in plants. Journal of Viorlogy, in press.

Ju HJ, Samuels T, Wang YS, Blancaflor E, Payton M, Samuels T D, Krishnamurthy K, Mitra R, Nelson R S, Verchot-Lubicz J (2005) The Potato virus X TGBp2 movement protein induces vesicles from the endoplasmic reticulum. Plant Physiol. Accepted.

Te J, Melcher U, Howard A R, Verchot-Lubicz J (2005) The Soilborne wheat mosaic virus 19K protein is a suppressor of gene silencing. Virology J. 2: 18.

Verchot-Lubicz J (2005) Invited Review: A new cell-to-cell transport model for Potexviruses. Molec Plant Microbe Interact. 18: 283-290.

Howard A R, Heppler M, Payton M E, Verchot-Lubicz J (2004) The Potato virus X TGBp1 is the primary viral factor that can move from cell to cell and induce plasmodesmata gating in several plant species. Virology 328: 185-197.

Driskel BA, Doss P, Littlefield LJ, Walker NR, Verchot-Lubicz J (2004) Soilborne wheat mosaic virus movement protein and RNA and wheat spindle streak mosaic virus coat protein accumulate inside resting spores of their vector, Polymyxa graminis. Mol Plant Microbe Interact 17: 739-748.

 
 
Selected Additional Publications:

An H, Melcher U, Doss P, Payton M, Guenzi AC, Verchot-Lubicz J (2003) Evidence that the 37 kDa protein of soil-borne wheat mosaic virus is a virus movement protein. J Gen Virol 84: 3153-3163.

Mitra, R, Krishnamurthy K, Blancaflor B, Payton M, Nelson R S, Verchot-Lubicz J (2003) The potato virus X TGBp2 protein association with the endoplasmic reticulum plays a role in but is not sufficient for viral cell-to-cell movement. Virology 312: 35-48.

Krishnamurthy K, Heppler M, Mitra R, Blancaflor E, Payton M, Nelson RS, Verchot-Lubicz J (2003) The Potato virus X TGBp3 protein associates with the ER network for virus cell-to-cell movement. Virology 309: 135-151.

Krishnamurthy K, Mitra R, Payton M E, Verchot-Lubicz J (2002) Cell-to-cell movement of the PVX 12K, 8K, or coat proteins may depend on the host, leaf developmental stage, and the PVX 25K protein. Virology 300: 269-281.

Driskel BA, Hunger RM, Verchot J (2001). Two resistance phenotypes to Soilborne wheat mosaic virus. Phytopathology (accepted).