Selection for low erucic acid and genetic mapping of loci affecting the accumulation of very long-chain fatty acids in meadowfoam seed storage lipids

Abstract

Erucic acid (22:1(13)) has been identified as an anti-nutritional compound in meadowfoam (Limnanthes alba) and other oilseeds in the Brassicales, a classification which has necessitated the development of low erucic acid cultivars for human consumption. The erucic acid concentrations of meadowfoam wild types (8%-24%) surpass industry standards for human consumption (<or=3%). The goals of the present study were to develop low erucic acid lines and identify loci affecting the accumulation of 22:1(13) and other very long-chain fatty acids (VLCFAs) in meadowfoam seed storage lipids. LE76, a low erucic acid line, was developed by 3 cycles of selection in an ethyl methanesulfonate-treated wildtype population. LE76 produced 3% 22:1(13), threefold less than the M0 population. Wildtype x LE76 F2 populations produced continuous, approximately normal erucic and dienoic acid distributions. Loss-of-function mutations apparently did not segregate and individuals with low 22:1(13) concentrations (<or=3%) were observed only in F2 populations from hybrids with L. alba subsp. alba wild types. The meadowfoam genome was mapped and scanned for quantitative trait loci (QTL) affecting VLCFA profiles in seed storage lipids by genotyping and phenotyping wildtype x low erucic acid F2 progeny. Composite interval mapping identified 3 moderately large-effect erucic acid QTL. The low erucic acid parent transmitted favorable alleles for 2 of 3 QTL, suggesting low erucic acid cultivars can be developed by combining favorable alleles transmitted by wildtype and low erucic acid parents.