Deborah A. Samac

The objectives of the research in my laboratory are to improve disease resistance and persistance of alfalfa stands, and to introduce new traits into alfalfa to increase utilization in new environments and for new uses. Current projects using genetically modified plants include: enhancing aluminum tolerance, improving forage quality, and increasing resistance to fungal pathogens. We are also investigating variation in the fungus causing spring blackstem and leaf spot (Phoma medicaginis var. medicaginis) and mechanisms of resistance to the fungus in alfalfa. Recently we have begun to use the new tools of functional genomics to identify genes involved in plant-microbe interactions using a model plant closely related to alfalfa, Medicago truncatula. This research involved developing and using expressed sequence tag microarrays and developing T-DNA tagged mutants.

Tesfaye, M., Silverstein, K.A., Bucciarelli, B., Samac, D. A., and Vance, C. P. 2006. Transcript profiling in Medicago species with the Affymetrix Medicago genechip. Funct. Plant Biol. (accepted April 9, 2006).

Tesfaye, M., Denton, M. D., Samac, D. A., and Vance, C. P. 2005. Transgenic alfalfa secretes a fungal endochitinase protein to the rhizosphere. Plant Soil 269: 233-243.

Samac, D. A., Tesfaye, M., Dornbusch M., Purev, S., and Temple, S. J. 2004. A comparison of constitutive promoters for expression of transgenes in alfalfa (Medicago sativa). Transgenic Res. 13:349-361.

Samac, D. A., Litterer, L., Temple, G., Jung, H. G., and Somers, D. A. 2004. Expression of UDP-glucose dehydrogenase reduces cell-wall polysaccharide concentration and increases xylose content in alfalfa stems. Appl. Biochem. Biotechnol. 116:1167-1182.

Samac, D. A. and Smigocki, A. C. 2003. Expression of oryzacystatin I and II in alfalfa increases resistance to the root-lesion nematode (Pratylenchus penetrans). Phytopathology 93:799-804.