Our research focuses on the plant-bacterium symbiosis present in the root nodules of legumes (e.g. pea, soybean and alfalfa). In this symbiosis, a new organ develops and is the site where atmospheric dinitrogen is reduced to ammonia by the bacterium. Ammonia is transferred to the plant where it is used for growth. This process is extremely important in both natural and agricultural environments and is the major natural source of biologically-available nitrogen. In collaboration with Dr. Carroll Vance (Department of Agronomy and Plant Genetics), Dr. Kathryn Vandenbosch (Department of Plant Biology) and Drs. Nevin Young and Deborah Samac (Department of Plant Pathology), we are taking a genomic approach to investigate the biochemical, molecular and genetic mechanisms that regulate the formation and function of nodules in the Rhizobium meliloti-Medicago truncatula symbiosis. Previous work by research at Minnesota and elsewhere have cloned and partially sequenced about 160,000 M. truncatula (an alfalfa relative) transcripts. Using the data and materials derived from this effort, we are using RNA interference to block the expression of individual genes as a means to determine the role that the genes have on nodule development and function.

Miller, S.S., Driscoll, B.T., Gregerson, R.G., Gantt, J.S. and Vance, C.P. (1998) Alfalfa Malate Dehydrogenase (MDH): Molecular Cloning and Characterization of Five Different Forms Reveals a Unique Nodule-Enhanced MDH. Plant J. 15:173-184.

Ascenzi, R. and Gantt, J.S. (1999) Molecular Genetic Analysis of the Drought-Inducible Linker Histone Variant in Arabidopsis thaliana. Plant Mol. Biol. 41:159-169.

Fedorova, M., van de Mortel, J., Matsumoto, P., Cho, J., Town, C.D., VandenBosch, K.A., Gantt, J.S. and Vance, C.P. (2002) Genome-Wide Identification of Nodule-Specific Transcripts in the Model Legume Medicago truncatula. Plant Physiol. 130:519-537.

Ivashuta, S., Liu, J., Liu, J., Lohar, D.P., Haridas, S., Bucciarelli, B.,   VandenBosch, K.A., Vance, C.P., Harrison, M.J. and Gantt, J.S . (2005) RNA Interference Identifies a Calcium-Dependent Protein Kinase Involved in Medicago truncatula Root Development. Plant Cell 17 :2911-2921.

Liu, J., Miller, S.S., Graham, M., Bucciarelli, B., Catalano, C.M,, Sherrier, D.J., Samac, D.A., Ivashuta, S., Fedorova, M., Matsumoto, P., Gantt, J.S., and Vance, C.P. (2006) Recruitment of Novel Calcium-Binding Proteins for Root Nodule Symbiosis in Medicago truncatula. Plant Physiol. 141:167-77.