Identification of a novel mutation in FAD2B from a peanut EMS mutant with elevated oleate content.

A Virginia type peanut mutant with more than 60% oleate content (E2-4-83-12) was selected from an EMS mutagenized population of LF2 (an export type peanut cultivar with 44.2% oleate) by near infrared reflectance spectroscopy. Cloning and sequencing of FAD2B from LF2 and E2-4-83-12 identified a novel mutation (C313T in the coding region) causing an H105Y substitution in the first histidine box of the FAD2B protein. GC-MS analysis of fatty acids in yeast cells harboring pYES2 with the mutated FAD2B detected no linoleate, confirming that FAD2B from E2-4-83-12 was dysfunctional. Loss-of-function FAD2A and FAD2B together contributed to elevated oleate phenotype of the peanut EMS mutant.