Genetic Studies on Lipoxygenase and Some Other Factors Possibly Associated With Soybean Oil Stability

Two soybean accessions, plant introductions (P.I.) 133226 from Indonesia and P.I. 408251 of the U.S. Department of Agriculture germplasm collection, were found to lack lipoxygenase-1 (linoleate: O(,2) oxidoreductase, EC 1.13.11.12). Spectrophotometric assays, measurement of oxygen uptake, electrophoresis, isoelectric focusing and immunochemical studies all confirm the lack of lipoxygenase-1 (L-1) in these two genotypes. The lack of L-1 was found to hold throughout seed development and the first seven days of germination. No soybean genotypes were found which lack lipoxygenase-2 or -3. The lack of L-1 activity is inherited as a simple recessive. No maternal or cytoplasmic effects for L-1 were seen. The gene symbol Lx is assigned to the allele coding for the presence of the L-1 protein and 1x(,1) for the allele coding for the lack of the L-1 protein. The presence of L-1 in seed extracts was found to increase the in vitro bleaching of carotene and chlorophyll. L-1 appears not to play a major role in oil stability. Heating soybean seeds increases the stability of the extracted oil. The increased stability of oil from heated seeds may be the result of increased phospholipid content, but is not related to changes in fatty acid composition, free fatty acid content or tocopherol content.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Agronomy

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Hildebrand, David F.

• Agriculture, Agronomy

Identifier

(UMI)AAI8218482

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/71573