Single-Nucleotide Polymorphism Of Fatty Acid Metabolism-related Genes In Soybean

With the oil content and its composition as the one of the key index of the quality of soybean,which is a dominant oilseed crop in our country as well as the world around,research on fatty acid metabolism-related genes is of great significance. By searching the fatty acid metabolism-related genes in soybean from Genbank Database(http://www.ncbi.ncbi.nlm.nih.gov) and TIGR Soybean Gene Index (http://www.tigr.org),followed by the homology BLAST through Genbank,40 single copy,nuclear-chromosomal genes corresponded to fatty acid metabolism have been selected,of which 23 are DNA fragments and 17 cDNA fragments.This thesis is in an attempt to discover the SNPs between the domestically major mapping population parents Kefeng1 and Nannong1138-2.The main features as follows:Through PCR amplification and DNA sequence analysis,23 sets of primers (57.5%) of 40 primers designed to genes selected in our investigation conduct good sequence results.SNPs loci have been found in 10 pairs(25%).Then,15 pairs which have bad results though PCR amplification and sequence analysis and 13 pairs without SNPs loci should have been redisgned in the other areas of the corresponding gene in order to get 28 another pairs of primers,of which 15 pairs(53.6%) have procured clear and reliable sequence results after experimental detection and SNPs have been discovered in 5 pairs(17.8%).No significant difference has been shown in the two experiments on the discovering efficiency of the SNPs.After cDNA having been converted into DNA based on the newly issued soybean genome sequence by JGI,the success rates of the discovering SNPs in the primers that have been redesigned for the third and the fourth time are 35%and 50%respectively.Therefore, a conclusion can be made that the discovering efficiency of the SNPs should be improved greatly by adopting NDA sequence as a template and redesigning the primers repeatedly.With a total sequencing length of 34 158bp,51 SNPs have been discovered altogether,among which 13 SNPs are in the coding region and 38 SNPs in the non-coding region.The frequencies of nucleotide polymorphism in both regions are 1.11SNP/kbp and 1.69SNP/kbp respectively,showing that the nucleotide polymorphism in the non-coding region of the fatty acid metabolism-related genes is also higher than in the coding region.Accordingly,the discovering efficiency of the SNPs can be increased effectively by designing the primer in the non-coding region of the functional genes.The 51 discovered SNPs loci are distributed in 27 genes,of which 15 with 31 SNPs and an average of 2.07 SNPs in each gene,encode key enzymes corresponded to fatty acid metabolism.The rest 12 genes with 20 SNPs all together and an average of 1.67 SNPs in each gene,encode other enzymes corresponded to fatty acid metabolism.The discovrery of these fatty acid metabolism-related genes has laid a solid foundation for mapping and cloning thses genes.