We are taking a combined genetic, molecular, and structural approach toward understanding the control of ovule development in higher plants. We are currently using Arabidopsis thaliana as as a model system to identify genes affecting this process. Through characterization of the mutant phenotypes and epistatic relationship among the genes we can propose hypothesis on the functions and interactions of the mutated genes. By combining this information with that gained from studies in other groups we have propose a working model of the genetic regulation of ovule development. This model will be refined (or corrected) through ongoing studies of the current mutants, isolation and characterization of clones of the corresponding genes, and analysis of newly isolated genes.
We using information derived from our analysis of the regulation of ovule development in the model plant Arabidopsis thaliana to study the nature of the changes that resulted in the variety of ovule forms in extant angiosperms. In one project we are studying the derivation of unitegmy (one integument) from bitegmy (two integuments) in the Impatiens. Impatiens is especially suitable for these studies because it includes unitegmic and bitegmic species, as well as species with an apparent intermediate state.
In collaboration with Daniel Nickrent of Southern Illinois University at Carbondale we are examining the extreme reduction in ovules of members of the order Santalales, which includes mostly parasitic plants. The Santalales includes species with bitegmic (two integuments) ovules but also has members with one or both integuments absent (unitegmic or ategmic respectively). In the most extreme reduction, ovules appear to be absent, never emerging from the placental tissues, and the embryo sac appears to develop directly within the placenta.
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Pages created by Shawn C. Baker and Charles S. Gasser, with extensive help from the rest of the lab.