Developmental and Structural Section
McKim, Sarah, M , Stenvik, Grethe-Elisabeth , Butenko, Melinka A , Kristiansen, Wenche , Cho, Sung Ki , Hepworth, Shelley R , Aalen, Reidunn B , Haughn, George .
The BLADE-ON-PETIOLE genes are essential for abscission zone formation.
Plants continually modify their aerial architecture by growing lateral organs such as leaves and flowers. However, plants form is also altered through active shedding or abscission of lateral organs. Separation occurs at anatomically distinct cell files called abscission zones (AZs) which often develop at the boundary of the lateral organ and the main plant body. Signals promoting abscission cause progressive enzymatic degradation of middle lamellae in the AZ leading to a loss of adhesion between the organ and plant body. We show that mutant Arabidopsis plants which lack BLADE-ON-PETIOLE1 (BOP1) and BOP2 gene functions display a range of developmental aberrations including a complete loss of floral organ abscission. We investigated the abscission phenotype of bop1 bop2 plants to determine the contribution of the BOP genes to the known abscission program. Scanning electron microscopy, petal breakstrength and histological sections of bop1 bop2 flowers showed an absence of floral AZ differentiation or activation. Similarly, vestigial cauline leaf AZs were also undifferentiated in bop1 bop2 suggesting that BOP gene function is essential to establish AZs in leaves as well as flowers. Interestingly, expression of several abscission-related marker genes was relatively unchanged in bop1 bop2 mutants, indicating that these AZ genes respond to positional cues independent of a presence of a differentiated AZ. We also show that the bop1 bop2 mutant lacks complete nectary glands that normally form at the floral receptacle adjacent to developing AZs. Taken together, these data suggest that BOP gene activity regulates multiple cell differentiation events in the proximal regions of inflorescence lateral organs. As a first step to determine whether BOP gene function is conserved, a phylogenetic analysis of the BOP genes will be presented.
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1 - University of British Columbia, Botany Department, Vancouver, British Columbia, V6T 1Z4, Canada
2 - University of Oslo, Department of Molecular Biosciences, Box 1041 Blindern, Oslo, N-0316, Norway
3 - University of Oslo, Department of Molecular Biosciences, PO Box 1041 Blindern, Oslo, N-0316, Norway
4 - University of Missouri, Division of Biological Sciences, 304 Life Science Center, University of Missouri, Columbia, MO, 65211, USA
5 - University of British Columbia, Botany, 6270 University Ave., Vancouver, BC, V6T 1Z4, Canada
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM