1. Genotypic and Phenotypic Variance in Soybean Oil
John Lindt1, David A. Lightfoot2, Yi-Chen Lee2
1SIUC Department of Microbiology, COS, 2Department of Plant Soil and Agricultural Systems, COAS, SIUC.
Introduction
Results
As gene-mapping techniques have improved, the understanding of genes and gene expression has greatly increased. In soybeans (Glycine max L. Merr.), many genes and their alleles are well mapped, but not all. One of the genes that is not thoroughly understood is the kasI gene. This gene is located on chromosome 5 within the protein and oil Quantitative Trait Locus found on Soybase (QTL; oil 10, 3, 13 and 35; protein 1 2, 9 and 34).The locus may also encode an AccI synthase paralog in some cultivars, an interrelated oil biosynthesis gene. Both are in a cluster linked to markers Satt236 and Satt200[1]. This QTL is believed to regulate certain aspects of oil content in soybean seeds. The kasI gene is believed to be responsible for regulation of many fatty acids including palmitic acid, a major fatty acid that is a component of soybean production[2]. The aim here was to compare genetic allele frequency (genotype) and oil content variation (phenotype) in different cultivars (‘Williams 82’ and ‘Essex’) of soybean with different alleles of the kasI gene; and to determine if there was a difference of alleles and oil content for the soybeans studied[1]. It was hypothesized that the kasI gene has an statistically significant effect on the regulation of oil content and composition. An association with palmitic acid content was a goal since it is a desired fatty acid since it melts in the mouth in chocolate and on the skin in cosmetics!
Table 1: Satt200 and Satt236 markers showed genetic variation in the Essex by Williams82 NILs during gel electrophoresis. Relative concentrations of oil, water, and protein content were measured. Oil content was expressed as a percent of weight. Students T-test was used to measure statistical significances of all traits measured.
Figure 3: Mean Fatty Acid Profile
Figure 3: The pathway of fatty acid biosynthesis in plants (after Buchanan et al 2001)
Objectives
The goal of this project is to determine if there is a genotypic and phenotypic relation between the kasI gene allele and oil production or quality in soybean through gene mapping and measuring phenotypic oil and fatty acid content.
Figure 4: Fatty acid compositions of the NILs
Methods
Crossbred Essex and Williams82 soybean cultivars were used to measure genetic variance. Their near isogenic lines (NILs) were labeled kas1-17. Soybeans were grown to VE emergence stage. Soybean sprouts were harvested for DNA extraction. PCR was used to amplify DNA. Gel electrophoresis was used to distinguish alleles for genetic markers Satt200 and Satt236 linked to the kasI gene. NILs were grown in the field from Seed were collected and NIR (near infrared reflectance) was used to measure oil, protein and water content. HPLC was used to measure individual fatty acid contents at Monsanto (St Louis, MO) using beans harvested in from the Agricultural Research Center at SIUC field Thanks are due to SIUC Alumnus (MS and PhD) and Monsanto employee Melody Hemmati for arranging that.
Results
Conclusion
Figure 1: Molecular markers for Satt236
SAT NILs scores
The results of this experiment support the hypothesis that the kasI allele affects production of total oil content and palmitic acid content in soybeans. Understanding of the kasI allele’s effect on the production of oil could be useful for a greater understanding of the oil production process in soybeans. Maximizing both oil and palmitic acid content could increase the impact of soybeans on both food and biofuel production as we move toward 9 billion people on a warming planet with less useful land…
Markers WxE1 WxE2 WxE3 WxE4 WxE5 Williams Essex
Figure 2: Palmitic Acid (Wiki)
Figure 3:
Soybeans (Google)
References
1. WWW. Soybase.org
2. Anghoram, K. et al. A Mutation in a 3-Keto-Acyl-ACP Synthase II Gene is Associated with Elevated Palmitic Acid Levels in Soybean Seeds. Crop Sci. 2006: