ARS | Publication request: THE CONTRIBUTION OF MULTIPLE GENES TO ONE TRAIT: LINOLENIC ACID PRODUCTION IN SOYBEAN SEEDS

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 22, 2003
Publication Date: N/A

Technical Abstract: Research on the model plant Arabidopsis thaliana has provided valuable resources to plant molecular genetics which can be utilized in more complex crop species. The streamlined diploid Arabidopsis genome often contains a single locus with a structural gene for a particular trait. Arabidopisis seed linolenic acid levels are largely dependent on the active expression of a microsomal omega-3 fatty acid desaturase enzyme encoded by the FAD3 gene. The objective of this work was to utilize this information to determine the basis of linolenic acid production in a crop species. Soybean is an important crop which requires additional tools for advanced genetic manipulation of valuable traits. Although soybean functions as a diploid with 20 linkage groups, it has a highly-duplicated genome, suggestive of a polyploid ancestor. Lowering linolenic acid levels in soybean seeds would enhance the value of the oil produced by increasing stability and reducing the need for hydrogenation and production of trans fatty acids. We identified three soybean FAD3 homologues and are investigating the contribution of each of these genes to soybean seed linolenic acid levels. The results of association experiments with mutant soybean FAD3 genes indicate an unequal contribution of the FAD3 genes to the trait, which appears at least in part due to differences in expression of the genes. Two of the three genes appear to be very closely related, and we are also interested in defining the evolutionary changes that have allowed their divergence in contribution to seed linolenic acid levels.