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Sue Loesch-Fries

Botany and Plant Pathology 

  • Associate Professor
Lilly Hall Room 1-331

Plant viruses are among the simplest of plant pathogens. Most contain fewer than a dozen genes. A growing number of plant virus genomes have been molecularly defined and cloned as cDNA. The goal of our research is to determine the roles of virus genes in virus replication and in disease development with the expectation that the results will lead to novel approaches for virus control.

The virus causing mosaic in alfalfa, alfalfa mosaic virus (AMV), has been the focus of our research. This virus is similar to the majority of plant viruses in that it has a single-stranded RNA genome. Synthesis of cDNAs to the entire AMV genome and determination of their sequences enabled us to study the individual genes in vitro and in plant protoplasts. We found that there are four proteins synthesized during infection that correspond to the expected products of the four genes encoded by AMV RNAs and to the proteins synthesized in vitro.

To study the role of virus genes in disease development and to devise and test strategies for the control of plant viruses, we transferred individual AMV genes into plant genomes. Plants which expressed the coat protein gene are similar to normal plants in morphology; however, they are resistant to AMV infection. The resistance is similar to natural cross protection, whereby infection with a virus protects a plant from subsequent infection by other strains of the same virus. Our studies, like studies of natural cross protection, suggest that coat protein interferes with an early event in virus replication.

An AMV gene involved in the movement of infection from one cell to the next was also transferred to tobacco plants. Our results suggest that this protein, like that in virus infections, is associated with the cell wall. Accumulation of this protein does not confer virus resistance, as does virus coat protein. Our goals are to determine more precisely where the protein accumulates in the plant cell and how it facilitates the cell-to-cell movement of infection.


Solomon, K., Lee, K. Z., Harris, M. T., Lee, Y., & Loesch-Fries, L. S. Methods For Manufacturing Nanoparticles With Tunable Length And High Stability Using Barley Stripe Mosaic Virus-Derived Biotemplates.

Selected Publications

Adigun, O. O., Retzlaff-Roberts, E. L., Novikova, G., Wang, L., Kim, B. S., Ilavsky, J., . . . Harris, M. T. (2017). BSMV as a Biotemplate for Palladium Nanomaterial Synthesis. Langmuir, 33(7), 1716-1724. doi:10.1021/acs.langmuir.6b03341

Adigun, O. O., Novikova, G., Retzlaff-Roberts, E. L., Kim, B. S., Miller, J. T., Loesch-Fries, L. S., & Harris, M. T. (2016). Decoupling and elucidation of surface-driven processes during inorganic mineralization on virus templates. Journal of Colloid and Interface Science, 483, 165-176. doi:10.1016/j.jcis.2016.07.028

Kim, B., Ruhl, G., Creswell, T., & Loesch-Fries, S. (2014). Molecular identification of a Tobacco mosaic virus isolate from imported petunias. Plant Health Progress, 15, 153-154.

Kim, B., Halk, E., Merlo, D., Nelson, S., & Loesch-Fries, S. (2014). Post translational modification of alfalfa mosaic virus movement protein in vivo. Archives of Virology, 159, 1787-1791.

Balasubramaniam, M., Kim, B., Hutchens-Williams, H., & Loesch-Fries, S. (2014). The photsystem II oxygen evolving complex protein, PsbP, ineracts with the coat protein of Alfalfa mosaic virus and inhibits virus replication. Molecular Plant Microbe Interactions, 10, 1094. Retrieved from http://First Look: doi:

Ibrahim, A., Hutchens, H., Berg, R., & Loesch-Fries, S. (2012). Alfalfa mosaic virus replicase proteins P1 and P2 localize to the tonoplast when in the presence of virus RNA. Virology, 433, 449-461.

Loesch-fries, L. (2006). Arabidopsis thaliana is a symptomless host of Alfalfa Mosaic Virus. Journal of General Virology.

Loesch-fries, L., & Kim, B. (in press). The importance of alfalfa mosaic virus coat protein dimers in the initiation of replication. Virology.

Botany and Plant Pathology, 915 West State Street, West Lafayette, IN 47907 USA, (765) 494-4614

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