Molecular Analysis of Mutant Alleles for Elevated Palmitate Concentration in Soybean

Abstract

ABSTRACTSoybean [Glycine max (L.) Merr.] oil with increased palmitate concentration may be useful for some food and industrial applications. Chemical mutagenesis was used to develop mutant alleles for elevated palmitate concentration that were designated as fap2(A21), fap4(A24), fap5(A27), fap6(A25), and fap7(A30) based on classical genetic analysis. The objective of our study was to determine whether the elevated palmitate phenotypes in any of these lines were associated with mutations in either of the two known 3‐ketoacyl‐ACP synthase II (KAS II) genes of soybean, GmKAS IIA and GmKAS IIB. Deoxyribonucleic acid sequence analysis revealed single nucleotide polymorphisms (SNPs) that differentiated mutant and wild‐type alleles in one of the GmKAS genes in lines A21, A25, A27, and A30 but not in A24. The identified SNPs resulted in nonconservative amino acid substitutions that were predicted to impair enzyme function. The fap2(A21) allele was associated with two consecutive SNPs within the GmKAS IIA gene, confirming its allelic relationship to fap2(C1727) that was known to have a mutant SNP within the same gene. The allele designated fap5(A27) also had a SNP within the GmKAS IIA gene, indicating that its designation should be changed to fap2(A27). The fap6(A25) and fap7(A30) alleles each contained a single SNP at different locations within the GmKAS IIB gene. We propose that the designation of the mutant allele in A25 remain fap6(A25) and that the allele in A30 be changed from fap7(A30) to fap6(A30).