Abstract: Oleic acid content of cultivated peanut (Arachis hypogaea L.) seeds is controlled by the activity of oleoyl-PC desaturase, encoded by two homologous genes (ahFAD2A and ahFAD2B), high oleic acid content results from the mutation of ahFAD2A and ahFAD2B, simultaneously. Two alleles of the ahFAD2A (wild type ahFAD2A-wt and mutation type ahFAD2A-m) exist in the normal oleic accessions, whereas only the ahFAD2A-m allele exists in the high oleic accessions. The ahFAD2A-m is a spontaneous mutation type of ahFAD2A-wt (G-to-A at site 448 bp resulting in a D to N at 150 amino acid position), which results in a dysfunctional desaturase. A specific PCR primer pair for the ahFAD2A amplification was developed in this study. According to the sequencing result of PCR production of the mutant and wild-type ahFAD2A alleles, mutant allele (ahFAD2A-m) accounted for 53.1% of the accessions in the mini-core collection from China, which was frequently found in subspecies hypogaea accessions but absent from subspecies fastigiata accessions; the highly positive correlation between the ahFAD2A-m and the higher oleic acid content was observed. A new SNP was found at the 417 bp (T/C) in the open reading frame (ORF), which did not result in the amino acid substitution, and was found no correlation between the SNP of 417 bp and the oleic content. These results will be helpful for the breeders to select the parent material in the peanut high oleic acid breeding program.

Key words: Peanut (Arachis hypogae L.), ahFAD2A, Allele, Oleic acid content