Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2017
Publication Date: 8/7/2017
Citation: Wang, M.L., Tonnis, B.D., Pinnow, D.L., Tallury, S.P. 2017. Identification of natural high-oleate mutants from the USDA Peanut Germplasm Collection. Meeting Abstract. WED01.
Technical Abstract: Natural genetic variation may exist in plant germplasm collections. Identifying genetic variation may provide useful materials for breeders to develop new cultivars. After screening 8,846 cultivated peanut germplasm accessions by gas chromatography analysis, we identified three natural mutant lines with 80% oleic acid. Two accessions, PIs 342664 and 342666, were originally collected from West Pakistan. The third, PI 162805, was originally collected from Liberia. FAD2A and FAD2B are the two major genes in peanuts coding for a fatty acid desaturase which converts oleic to linoleic acid. Functional mutations in one or both genes can alter the oleate level. By sequencing the coding region of these two genes, we identified a substitution of G448A in FAD2A and a substitution of C301G in FAD2B for the first two mutant lines. The substitution in FAD2A is the same as a previously identified one, resulting in a missense amino acid substitution of D150N; but the substitution in FAD2B is a new one, resulting in H101D. The new amino acid substitution on FAD2B is located in the first histidine box (one of the active sites) of the fatty acid desaturase and may significantly decrease its activity. The mutation on FAD2A and FAD2B for PI 162805 were identical to the high-oleate line F435 containing a substitution of G448A on genome A and an “A” insertion on genome B. All of these mutants belong to subspecies hypogaea based on their morphology with no flowers on the main stem; but F435, a previously identified natural high oleate mutant, is classified as subspecies fastigiata since it does have flowers on the main stem. Therefore, we have identified a class of natural mutants from the subspecies hypogaea and provided new genetic resources for breeders to use.