Association Analysis of Fatty Acid Content in Soybeans Accessions

The quality of soybean oil depends greatly upon its fatty acid components, including palmitic, stearic, oleic, linoleic and linolenic acid. In this study we report association mapping of fatty acids using 142 SSR loci markers in soybean accessions grown in Brazilian environments. Genomic DNA samples were prepared from a lyophilized bulk of leaf tissue of 10 plants of each accession by mini-prep procedure. Fatty acids in soybean seeds grown during 2010 and 2011 were estimated by gas chromatography. Primers and genetic distance (cM) of each locus were obtained from soybean genetic resources database. Amplicons were obtained in a touchdown program and visualized in 4300S DNA Analyzer (Li-cor Co). The 94 soybean accessions showed mean of two years of 11.16, 3.32, 17.40, 58.02 and 7.49% of palmitic, stearic, oleic, linoleic and linolenic acid content, respectively. No heterogeneity was detected in the frequency distribution of the fatty acids content in both years according Kolmogorov-Smirnov two-sample test. In relation to molecular analyses, the 1142 alleles showed that the soybean accessions were structured in two subpopulations. Analyze of the genome-wide linkage disequilibrium(LD) showed that pairs of SSR loci having an LD level of r²>0.05 were rare and the scatter plots of the LD values based only on the r² indicated one marker in each 7 cM, if r²>0.1 was the cutoff level. Thirty-two putative fatty acid SSR loci were identified on the basis of highly significant markers. Several are located in regions where fatty acid content has been mapped.

Financial support: BIOEN-FAPESP