Steven A. Lommel

 
 
 
Professor of Plant Pathology

Department of Plant Pathology
2220 Toxicology Building
Box 7342
Raleigh, NC 27695-7342

Tel: (919) 515-6990
FAX: (919) 515-7169

Research: 

The research program in my laboratory has focused on a small RNA plant virus, red clover necrotic mosaic virus (RCNMV) as a model system to study the molecular mechanisms of plant viral pathogenesis (click here to see a model of the virion structure or a representation of the RCNMV genome). Over the past decade the laboratory has focused on using RCNMV to study the molecular mechanisms of virus movement and systemic infection. We genetically established that the virus-encoded movement protein (MP) is necessary for local movement of the virus infection and that the MP and capsid protein (CP) are essential for long-distance transport. A saturation mutagenesis study indicated that the MP has a number of functional domains, including those for binding to single-stranded RNA, targeting to plasmodesmata, modification of plasmodesmata, trafficking RNA from cell to cell, and effecting long-distance transport. In collaboration with Dr. Bill Lucas, UC Davis, we showed that a viral RNA-MP complex is formed and is transported through the plasmodesmata. Recently we have generated compelling genetic evidence that the MP and capsid protein must interact in order to facilitate long-distance transport. We are currently determining whether the virus needs to be in the form of a virion to facilitate long-distance transport.

In parallel with the viral studies, a postdoctoral researcher in the laboratory has been developing a genetic screen in Arabidopsis and in Nicotiana benthamiana to identify host factors necessary for facilitating cell-to-cell and systemic infection of the virus. Again, the goal of this work is to understand the process of viral systemic infection in sufficient detail to design control strategies that prevent the establishment and spread of a virus infection.

Selected Publications: 

Kim, K. H., and Lommel, S. A. 1998.  Sequence element required for efficient -1 ribosomal frameshiting in red clover necrotic mosaic dianthovirus. Virology 250, 50-59.

Sit, T. L., Vaewhongs, A. A., and Lommel, S. A.  1998. RNA-mediated trans-activation of transcription from a viral RNA.  Science 281, 829-832.

Wang, H.-L., Wang, Y., Giesman-Cookmeyer, D., Lommel, S. A., and Lucas, W, J. 1998.  Mutations in viral movement protein alter systemic infection and identify an intercellular barrier to entry into the phloem long-distance transport system. Virology 245, 75-89.

Vaewhongs, A. A. and Lommel, S. A. 1995.  Virion formation is required for the long-distance movement of red clover necrotic mosaic virus in movement protein transgenic plants. Virology 212, 607-613.

Giesman-Cookmeyer, D., Silver, S., Vaewhongs, A. A., Lommel, S. A., and Deom, C. M. 1995. Tobamovirus and Dianthovirus movement proteins are functionally homologous. Virology 213, 38-45.

Kim, K. H., and Lommel, S. A. 1994.  Identification and analysis of the site of  -1 ribosomal frameshifting in red clover necrotic mosaic virus. Virology  200, 574-582.

Xiong, Z., Kim, K. H., Giesman-Cookmeyer, D., and Lommel, S. A. 1993. The roles of the red clover necrotic mosaic virus capsid and cell-to-cell movement proteins in systemic infection. Virology  192, 27-32.

Xiong, Z., Kim, K. H., Kendall, T. L., and Lommel, S. A. 1993. Synthesis of the putative red clover necrotic mosaic virus RNA polymerase by ribosomal frameshifting in vitro. Virology 193, 213-221.

Giesman-Cookmeyer, D., and Lommel, S. A. 1993.  Alanine scanning mutagenesis of a plant virus movement protein identifies three functional domains.  The Plant Cell  5: 973-982.

Fujiwara, T., Giesman-Cookmeyer, D., Ding, B., Lommel, S. A. and Lucas, W. J. 1993. Cell-to-cell trafficking of macromolecules through plasmodesmata potentiated by the red clover necrotic mosaic virus movement protein.  The Plant Cell  5, 1783-1794.

Kendall, T. L., and Lommel, S. A. 1992.  Nucleotide sequence of carnation ringspot dianthovirus RNA-2. J. Gen Virol.73, 2479-2482.
 

Selected Book Chapters

Lommel, S. A., Hemenway, C. L.  2000.  Manipulating viral RNA transcription.  Genetic Engineering: Principles and Methods.  Volume 22. In preparation.

Lommel, S. A., Callaway, A., Giesman-Cookmeyer, D., Gillock, E., and Sit, T. L.  2000.  The multifunctional nature of plant viral coat proteins.  Annual Review of Phytopathology.  In preparation.

Giesman-Cookmeyer and Lommel, S. A. 2000. Dianthoviruses. Encyclopedia of Plant Pathology. Wiley Press.  In press.

Giesman-Cookmeyer, D., Sit, T., and Lommel, S. A. 1999. Tombusviridae and Allies. Encyclopedia of Life Sciences.  Nature Publishing Group, London. www.els.net

Lommel, S. A., Martelli, G. P., and Russo, M. 1999. Virus Taxonomy. Seventh Report of the International Committee on the Taxonomy of Viruses.  F. A. Murphy ed.  Academic Press. pgs. 791-825.

Lommel, S. A. 1999. Plant virus expression, packaging, and movement.  Noble Foundation 10-year anniversary symposium of the Plant Biology Division proceedings.

Lommel, S. A. 1999. The Dianthoviruses. In Encyclopedia of Virology. 2nd Edition, Academic Press. A. Granoff and R. G. Webster, editors. 1, 403-409.

Lommel, S. A. 1999. The Machlomoviruses. In Encyclopedia of Virology. 2nd Edition, Academic Press.  A. Granoff and R. G. Webster, editors. 2, 935-939.