Identification of a mutant from Arachis veigae with enhanced seed oleic and very long-chain fatty acid content

Authors: Tonnis, Brandon; Wang, Ming; Tallury, Shyamalrau - Shyam; TISHCHENKO, VIKTOR - University Of Georgia; STALKER, H. THOMAS - North Carolina State University

Submitted to: Applied Biological Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2019
Publication Date: 3/1/2019
Publication URL: https://handle.nal.usda.gov/10113/6326044
Citation: Tonnis, B.D., Wang, M.L., Tallury, S.P., Tishchenko, V., Stalker, H. 2019. Identification of a mutant from Arachis veigae with enhanced seed Oleic and very long chain acid content. Applied Biological Chemistry. 62:9. https://doi.org/10.1186/s13765-019-0420-x.
DOI: https://doi.org/10.1186/s13765-019-0420-x

Interpretive Summary: Crop wild relatives (CWR) are potential sources of genetic variation for improving cultivated crops by enhancing nutritional traits or disease resistance. However, research on peanut wild relatives has been limited to date. One important trait in peanut is the composition of the seed oil, specifically the proportion of oleic acid, an important mono-unsaturated fat that increases oil shelf life and has important nutritional benefits. From screening over 200 accessions in 45 wild peanut species, we identified a mutant line PI 688970 from Arachis veigae that has increased oleic acid (55.5%) relative to other A. veigae accessions (average 18.3%) and other Arahcis species (average 37.0%). Upon further study, we found a mutation in the fatty acid desaturase (FAD2) gene that is responsible for the higher level of oleic acid. A. veigae accessions also have unique concentrations of other fatty acids relative to cultivated peanuts and other Arachis species. Because of these unique oil traits and because the species is the most widely dispersed geographically, PI 688970 can be considered an important CWR genetic resource.

Technical Abstract: High oleate is an important seed quality trait frequently incorporated in peanut varieties. Crop wild relatives (CWR) are potentially useful genetic resources for cultivar improvement through genetic introgression; but for wild peanut species, many chemical or nutritional traits are not well characterized. A mutant from Arachis veigae S. H. Santana & Valls (2n = 2x = 20), a wild species within the Arachis genus, with increased oleic acid content was identified from screening 209 accessions of 45 wild species using gas chromatography (GC). The A. veigae (formerly A. sylvestris) accession, Grif 7610 contained 55.5% oleic acid in seeds, significantly higher than the average (18.3%) of other accessions within the same species and also significantly higher than the average (37.0%) of all wild peanut accessions evaluated. A C37T substitution was identified by sequencing the coding region of FAD2, resulting in the nonsense mutation of Q13* (a premature stop codon). This functional mutation may significantly reduce the fatty acid desaturase (FAD) activity and result in the enhanced oleate level. Because A. veigae is widely dispersed geographically, other potentially useful traits may be present. While these other traits can be introduced from A. veigae into cultivated peanut through introgression, the high oleate trait should also be considered. The level of oleic acid can be simultaneously enhanced along with other targeted traits for peanut cultivar improvement. A. veigae also contained a high percentage of very long-chain (C greater than or equal to 22) fatty acids, and their variation identified in this study is also discussed and compared with other species.