Insights into the novel members of the FAD2 gene family involved in high-oleate fluxes in peanut

The FAD2 gene family is functionally responsible for the conversion of oleic acid to linoleic acid in oilseed plants. Multiple members of the FAD gene are known to occur in several oilseed species. In this study, six novel full-length cDNA sequences (named as AhFAD2-1, -2, -3, -4, -5, and -6) were identified in peanut (Arachis hypogaea L.), an analysis of which revealed open reading frames of 379, 383, 394, or 442 amino acids. Sequence comparisons showed that AhFAD2-1 and AhFAD2-2 shared 76% identity, while AhFAD2-2, -3, and -4 displayed highly significant homology. There was only 27% identity overlap between the microsomal ω-6 fatty acid desaturase and the chloroplast ω-6 fatty acid desaturase encoded by AhFAD2-1, -2, -3, -4, and AhFAD2-5, -6, respectively. The phylogeny tree of FAD2 transcripts showed five major groups, and AhFAD2-1 was clearly separated from other groups. Analysis of AhFAD2-1 and AhFAD2-2 transcript distribution in different peanut tissues showed that the AhFAD2-1 gene showed upward of...