Overview

Our research is focused on the genetic analysis of evolution of mating systems in the crucifer family, which include the economically important Brassica crops as well as the Arabidopsis thaliana model plant species. We study the major determinant of the outbreeding mode of mating in the crucifer family, namely self-incompatibility (SI), an intra-specific mating barrier that prevents self-fertilization in plants with functional gametes and thus allows them to avoid the deleterious effects of inbreeding. We use two major approaches: 1) genetic analysis of inter-specific crosses between self-incompatible and self-fertile species, and 2) transgenic inter-specific complementation experiments in which SI specificity-determining genes from a self-incompatible species are introduced into a self-fertile species. Our successful transfer of the SI trait into the self-fertile A. thaliana model plant by transformation with SI specificity-determining genes from its self-incompatible sister species, A. lyrata, has uncovered previously unknown variation in expression of SI among different A. thaliana populations. This cryptic natural variation can now be exploited using the vast molecular genetic resources available for A. thaliana to elucidate the genetic mechanisms underlying transitions between outcrossing and self-fertilizing mating systems.

Research Focus

Our research is focused on the genetic analysis of evolution of mating systems in the crucifer family, which include the economically important Brassica crops as well as the Arabidopsis thaliana model plant species.

Instruction Focus

I have designed and continue to teach BioPl 343 and 347 with the goal of providing undergraduate students with the theoretical background for plant genetic engineering and with hands-on experience in plant molecular genetic methodology.

Additional Links

• Nasrallah Lab
• Link to CALS Research portal
• Link to CALS Impact statements

Selected Publications

• Liu, P., Sherman-Broyles, S., Nasrallah, M.E., and Nasrallah J.B. 2007. A cryptic modifier causing transient self-incompatibility in Arabidopsis thaliana. Curr. Biol. 17: 734-740.
• Nasrallah, J.B., Liu, P., Sherman-Broyles, S., Schmidt, R., and Nasrallah, M.E. 2007. Epigenetics mechanisms for breakdown of self-incompatibility in inter-specific hybrids. Genetics 175: 1965-1973.
• Sherman-Broyles, S., Boggs, N., Farkas, A., Liu, P., Vrebalov, J., Nasrallah, M.E. and Nasrallah, J.B. 2007. S locus genes and the evolution of self-fertility in Arabidopsis thaliana. Plant Cell 19: 94-106.
• Yogeeswaran, K., Frary A., York, T.L., Amenta, A., Lesser, A.H., Nasrallah, J.B., Tanksley, S.D., and Nasrallah, M.E. 2005. Comparative genome analyses of Arabidopsis spp. ? Inferring chromosomal rearrangement events in the evolutionary history of A. thaliana. Genome Res. 15: 505-515.
• Nasrallah, M.E., Liu, P., Sherman-Brolyes, S., Boggs, N.A., and Nasrallah, J.B. 2004. Natural variation in expression of self-incompatibility in Arabidopsis thaliana: implications for the evolution of selfing. Proc. Natl. Acad. Sci. USA 101: 16070-16074.
• Nasrallah, M.E., P. Liu, and Nasrallah, J.B. 2002. Generation of self-incompatible Arabidopsis thaliana by transfer of two S locus genes from A. lyrata. Science 297: 247-249.
• Kusaba, M., Tung, C.-W., Nasrallah, M.E., and Nasrallah, J.B. 2002. Monoallelic expression and dominance interactions in anthers of self-incompatible Arabidopsis lyrata. Plant Physiol. 128: 17-20.
• Kachroo, A., Schopfer, C.R., Nasrallah, M.E., and Nasrallah, J.B. 2001. Allele-specific receptor-ligand interactions in Brassica self-incompatibility. Science 293: 1824-1826.
• Kusaba, M., Dwyer, K.D., Hendershot, J., Vrebalov, J., Nasrallah, J.B., and Nasrallah, M.E. 2001. Self-incompatibility in the genus Arabidopsis: Characterization of the S locus in the outcrossing A. lyrata amd its autogamous relative A. thaliana. Plant Cell 13: 627-643.
• Schopfer, C.R., Nasrallah, M.E., and Nasrallah, J.B. 1999. The male determinant of self-incompatibility in Brassica. Science 286: 1697-1700.

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