| Abstract Detail
Lipids Molina, Isabel [1], Ohlrogge, John [2], Pollard, Mike [2]. Lipid polyester deposition in seeds of Brassica napus and Arabidopsis thaliana mutants. Mature seeds of Arabidopsis thaliana and Brassica napus contain a complex mixture of aliphatic monomers derived from non-extractable lipid polyesters. These include structures typical of both cutin and suberin, apoplastic lipid polymers that contribute to seed coat permeability, seed dormancy, and may influence pathogen resistance. Despite their important physiological roles, little is known about surface lipid polyesters associated with seed coats. We have previously reported the development of a method to analyze these compounds in whole seeds (Molina et al., 2006). In the present study, we have applied this method to B. napus developing seeds to analyze the timing of deposition of lipid polyester monomers. Deposition of the different polyester monomers occurred with distinct temporal patterns of accumulation. Based on the observed pattern of deposition, we hypothesize that suberin would localize at the chalazal region, presumably sealing openings in mature seeds. Candidate genes for monomer synthesis and assembly were identified by examining transcriptional co-regulation patterns and tissue specificity of gene expression across publicly available microarray data. Several Arabidopsis knockout mutants for selected genes were examined, and variance in both polyester monomer load and composition was observed. Analyses of the compositional differences will be presented from a biosynthetic perspective and will be correlated with seed coat permeability to dyes. Furthermore, stable transgenic plants expressing promoter::YFP fusions have been generated to evaluate expression of the selected genes in the seed coat integuments by laser scanning confocal microscopy. This indirect approach was used to determine the various locations of the polyesters in the seed coat layers.
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1 - Michigan State University, Plant Biology, 362 Plant Biology Building, East Lansing, Michigan, 48824-1312, USA
2 - Michigan State University, Plant Biology
Keywords:
lipid polyesters
seed coat
Brassica napus
Arabidopsis thaliana
knockout mutants.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P21008
Abstract ID:1201 |
