28:	The Isolation And Characterization Of Leunig, A Regulator Of Arabidopsis Floral Organ Identity And Organ Shape.

Authors:	Conner, Joann , A.(A)Liu, Zhongchi(A)
Affiliations:	(A): University of Maryland (B): University of Georgia
Presenter:	Conner, Joann A., jaconner@tifton.cpes.peachnet.edu

Floral development in Arabidopsis has been extensively studied through the utilization of floral mutants. Floral development in Arabidopsis is controlled by the activity of homeotic genes that specify floral organ identity and by the activity of cadastral genes which maintain the boundaries of activity of the homeotic genes. LEUNIG (LUG) is a cadastral gene involved in establishing the boundary of AGAMOUS (AG) expression during floral development. Ectopic expression of AG in lug mutants causes the conversion of sepals to carpels and petals to stamen-like filaments or absent. lug flowers also contain a reduced number of stamen and incomplete carpel fusion. In addition to the cadastral activity of LUG in floral development, lug mutants have reduced female fertility and exhibit leaves and floral organs that are narrower than wild type. Reduced fertility and narrow organs are not the effect of ectopic AG expression and suggests the involvement of LUG activity in the regulation of several different developmental processes. A map-based cloning approach is being used to isolate LUG, located between marker g8300 and AtH1 on chromosome 4. By focusing on the genetic and molecular analyses of LUG, the control mechanisms for region-specific gene expression and pattern formation will be dissected in Arabidopsis.