Ph.D. Purdue University 1989
Office: WO 4223B
Phone No: 419.530.1549
As global populations increase, it is important to ask the question, “How are we going to feed all of these people?” Like humans, plants are exposed to a variety of stress. The more effectively we can help plants deal with stress, the greater crop productivity would increase and that would help to feed the growing number of hungry people. Our research examines how we can help plants to better deal with stress. Currently, we are studying two different kinds of stress that plants are exposed to, diseases and heavy metal pollutants.
The disease that we are studying is caused by a pathogen called Cauliflower mosaic virus (CaMV). CaMV infects a wide variety of plants within the mustard family including, turnips, brussels sprouts, cauliflower, broccoli, and cabbage. The virus is transmitted by insects from infected to healthy plants. Once the virus is delivered into the inside of a healthy plant cell, the virus particle opens up, releasing the viral genomic DNA into the plant cell nucleus. Inside the plant cell nucleus the viral genomic DNA is transcribed to make viral RNAs. The viral RNAs are then used to make both new viral DNAs and proteins, which are assembled into new virus particles, to repeat the cycle. Just as with humans making a large number of complex products such as cars, the production and assembly of virus components does not occur randomly within the cell, but in specialized “factories.” Viral factories are where most CaMV processes occur. In our laboratory, we are studying how these factories work. We are examining the major constituent of viral factories, a protein called P6, and are determining how its interactions with viral and host proteins allow it to make these factories. Our most recent data indicate that mutations affecting the organization of factories drastically delays viral infection and shows what a good target this protein is for inhibiting viral infection. Such research will lead us to understand not just CaMV, but other types of viruses so we can stop them.
The heavy metal pollutant that we are studying is copper (Cu), an essential element for all organisms. However, if Cu levels get too high, they can cause toxicity effects, which harm the organism, in our case, the plant. We and others, have discovered that the element silicon (Si) helps plants to better deal with a variety of stress such as Cu toxicity. This is very interesting because Si confers many beneficial effects on plants and yet, we have no idea how this element works. Not only does Si help the plant to better deal with stress but stress also induces the uptake of Si into plant leaves. This means that Si uptake is regulated and that there must be transporter that brings Si into plants. We have recently discovered a Si transporter and are currently working to understand how it functions and is regulated. Such an understanding will permit us to better help plants deal with stress and thereby, improve crop productivity.Current Students
Christopher Flora Ph.D.
Current Laboratory Grants
Specific Cooperative Agreement: Analysis of mechanisms involved in induction of abiotic or biotic stress tolerance in horticulture crops through nutrition or temperature.
1. Agama, K., S. Beach, J. Schoelz, and Leisner, S.M. (2002) Cauliflower mosaic virus gene VI conditions resistance-breakage in Arabidopsis ecotype Tsu-0. Phytopathology 92: 190-196.
2. Li, Y., and Leisner, S.M. (2002) Multiple domains within the Caulimovirus gene VI product interact with the full-length protein. Molecular Plant-Microbe Interactions 15: 1050-1057.
3. Leisner, S.M and Neher, D. (2002) Third position codon composition suggests two classes of genes within the cauliflower mosaic virus genome. Journal of Theoretical Biology. 217: 195-201.
4. Hapiak, M., Li., Y., Agama, K., Swade, S., Okenka, G., Falk, J., Khandekar, S., Raikhy, G., Anderson, A., Pollock, J., Zellner, W., Schoelz, J., and Leisner, S. M. (2008). Cauliflower mosaic virus gene VI product N-terminus contains regions involved in resistance-breakage, self-association and interactions with movement protein. Virus Research 138: 119-129.
5. Rajakaruna, P., Khandekar, S., Meulia, T., and Leisner, S.M. (2007) Identification and host relations of Turnip ringspot virus, a novel comovirus from Ohio. Plant Disease 91: 1212-1220.
6. Li, J., Frantz, J., and Leisner, S. (2008) Alleviation of Copper Toxicity In Arabidopsis thaliana By Silicon Addition To Hydroponic Solutions. Journal of the American Society of Horticultural Science 133: 1-8.
7. Khandekar, S., He, J., and Leisner, S. (2009) Complete Nucleotide Sequence Of The Toledo Isolate Of Turnip ringspot virus. Archives of Virology 154: 1917-1922.
8. Frantz, J.M., Khandekar, S., Leisner, S. (2011) Silicon differentially influences copper toxicity response in silicon-accumulator and non-accumulator species. Journal of the American Society for Horticultural Science 136: 329-338.
9. Khandekar S. and S. Leisner. (2011) Soluble Silicon Modulates Expression Of Arabidopsis thaliana Genes Involved In Copper Stress. Journal of Plant Physiology 168: 699-705.
10. Raikhy, G., Krause, C., and Leisner, S.M. (2011). The Dahlia mosaic virus gene VI product N-terminal region is involved in self-association. Virus Research 159: 69-72.
11. Zellner, W., Frantz, J., and Leisner, S. (2011) Silicon delays Tobacco ringspot virus systemic symptoms in Nicotiana tabacum. Journal of Plant Physiology 168: 1866-1869.
12. Lutz, L., Raikhy, G., and Leisner, S.M. (2012) Cauliflower mosaic virus major inclusion body protein interacts with the aphid transmission factor, the virion-associated protein and gene VII product. Virus Research 170: 150-153.
13. Angel, C.A., Lutz, L., Yang, X., Rodriguez, A., Adair, A., Zhang, Y., Leisner, S.M., Nelson, R.S., Schoelz, J.E., (2013). The P6 protein of Cauliflower mosaic virus interacts with CHUP1, a plant protein which moves chloroplasts on actin microfilaments. Virology 443: 363-374.
14. Akkuratov, E.E., Walters, L., Saha-Mandal, A., Khandekar, S., Crawford, E., Zirbel, C.L., Leisner, S., Prakash, A., Fedorova, L., Federov, A. (2014) Bioinformatics analysis of plant orthologous introns: identification of an intronic tRNA-like sequence. Gene 548: 81-90.
15. Rodriguez, A., Angel, C.A., Lutz, L., Leisner, S.M., Nelson, R.S., Schoelz, J.E., (2014). Association of the P6 protein of Cauliflower mosaic virus with plasmodesmata and plasmodesmal proteins. Plant Physiology 166: 1345-1358.
16. Lutz, L., Okenka, G., Schoelz, J., and Leisner, S.M. (2015). Mutations within a 35 amino acid region of P6 influence, self-association, inclusion body formation and Caulimovirus infectivity. Virology, 476: 26-36.
17. Schoelz, J.E., Angel, C.A., Nelson, R.S., Leisner, S.M. (2016). A model for intracellular movement of Cauliflower mosaic virus: the concept of the mobile virion factory. Journal of Experimental Botany 67: 203