Insights into the Novel FAD2 Gene Regulating Oleic Acid Accumulation in Peanut Seeds with Different Maturity.

AhFAD2 is a key enzyme catalyzing the conversion of oleic acid into linoleic acid. The high oleic acid characteristic of peanut mainly comes from the homozygous recessive mutation of and genes (aabb). However, even in high-oleic-acid varieties with the aabb genotype, the oleic acid content of seeds with different maturity varies significantly. Therefore, in addition to and , other members or regulators may be involved in this process. Which genes are involved in the regulatory processes associated with seed maturity is still unclear. In this study, four stable lines with different genotypes (AABB, aaBB, AAbb, and aabb) were used to analyze the contents of oleic acid and linoleic acid at different stages of seed development in peanut. Three new genes (, , and ) were cloned based on the whole-genome sequencing results of cultivated peanuts. All peanut genes showed tissue preference in expression; however, only the expression level of was positively correlated with the linoleic acid concentration in peanut seeds. These findings provide new insights into the regulation of oleic acid accumulation by maturity, and AhFAD2-7 plays an important role in the maturity dependent accumulation of oleic acid and linoleic acid in peanut.