Stephen L Dellaporta

Prof Mol Cell & Dev Biology

Research Interests

Functional genomics; plant molecular genetics; marine genomics; biofuels

Current Projects

HarvestPlus, a collaborative project to biofortify maize for developing countries
NSF, Evolutionary genetics of allorecognition in a marine hydroid
NIH, Molecular basis for allorecognition
Various, Sex determination in maize

Research Summary

My lab is interested in the study the pathway of sex determination in maize, a process that involves cell death and cell arrest. Zea mays is an ideal organism for molecular genetic studies on the sex determination process. Maize produces unisexual flowers, called florets in grasses, with pistillate (female) florets formed in the ear and staminate (male) florets formed in the tassel. Initially, these floral meristems are bisexual (cosexual). Through the action of sex determination (SD) genes they later become unisexual by the selective elimination of one sex and maturation of preformed organ primordia of the opposite sex. The formation of staminate florets in the tassel involves programmed death of pistil subepidermal cells and sexual maturation of stamen initials. Our mission is to understand these pathways in maize, including the associated processes of tasselseed-mediated pistil cell death, silkless-mediated pistil cell protection, and gibberellin (GA)-mediated stamen cell arrest.

We are also interested in unraveling the origin and early diversification of Antp superclass homeobox genes (including Hox genes and the related ParaHox and NK-like genes) in Trichoplax adhaerens. Trichoplax is a simple diploblastic metazoan with the smallest known animal genome, only ten times that of the bacterium E. coli. Our project includes testing the hypothesis that physical clustering of homeobox genes is a unique character of animal genomes, exploited repeatedly during animal evolution. In pursuing this goal, we are developing Trichoplax adhaerens as a new model system for primitive animal studies along with comparative genetic data from sponges, cnidarians, and choanoflagellates.

Selected Publications

  • Acosta, I.F., Laparra, H., Romero, S.P., Schmelz, E., Hamberg, M., Mottinger, J.P., Moreno, M.A., and Dellaporta, S.L. (2009). tasselseed1 is a lipoxygenase affecting jasmonic acid signaling in sex determination of maize. Science (New York, NY 323, 262-265.
  • Nicotra, M.L., Powell, A.E., Rosengarten, R.D., Moreno, M., Grimwood, J., Lakkis, F.G., Dellaporta, S.L., and Buss, L.W. (2009). A hypervariable invertebrate allodeterminant. Curr Biol 19, 583-589.
  • Schierwater, B., Eitel, M., Jakob, W., Osigus, H.J., Hadrys, H., Dellaporta, S.L., Kolokotronis, S.O., and Desalle, R. (2009). Concatenated analysis sheds light on early metazoan evolution and fuels a modern "urmetazoon" hypothesis. PLoS biology 7, e20.
  • Srivastava, M., Begovic, E., Chapman, J., Putnam, N.H., Hellsten, U., Kawashima, T., Kuo, A., Mitros, T., Salamov, A., Carpenter, M.L., et al. (2008). The Trichoplax genome and the nature of placozoans. Nature 454, 955-960.
  • Poudyal, M., et al. (2007). Embryonic chimerism does not induce tolerance in an invertebrate model organism. Proc. Natl. Acad. Sci. (USA) 104:4559-4564.
  • Kamm, K., Schierwater, B., Jakob, W., Dellaporta, S.L., and Miller, D.J. (2006). Axial patterning and diversification in the cnidaria predate the Hox system. Curr. Biol. 16:920-926.

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