Genetic mapping of QTLs controlling fatty acids provided insights into the genetic control of fatty acid synthesis pathway in peanut (Arachis hypogaea L.)

Authors: Wang, Ming; KHERA, PAWAN - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India; PANDEY, MANISH - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India; WANG, HUI - University Of Georgia; QIAO, LIXIAN - University Of Georgia; FENG, SUPING - University Of Georgia; Tonnis, Brandon; Anglin, Noelle; Pinnow, David; Holbrook, Carl - Corley; CULBREATH, ALBERT - University Of Georgia; VARSHNEY, RAJEEV - International Crops Research Institute For Semi-Arid Tropics (ICRISAT) - India; Guo, Baozhu

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2015
Publication Date: 4/7/2015
Citation: Wang, M.L., Khera, P., Pandey, M.K., Wang, H., Qiao, L., Feng, S., Tonnis, B.D., Barkley, N.L., Pinnow, D.L., Holbrook Jr, C.C., Culbreath, A.K., Varshney, R.K., Guo, B. 2015. Genetic mapping of QTLs controlling fatty acids provided insights into the genetic control of fatty acid synthesis pathway in peanut (Arachis hypogaea L.). PLoS One. 10(4):e0119454. doi: 10.1371/journal.pone.0119454.

Interpretive Summary: Peanut is a major oil crop. Peanut seeds contain around 25% protein and 50% oil. Fatty acid composition determines the oil quality which has high relevance to consumer health, flavor, and the shelf life of commercial products. Efforts in improvement of peanut oil quality have been a breeding objective. In this study, two segregation populations with two years oil fatty acid data were used to identify genomic regions in the peanut genome which are controlling these quality traits. There was a significantly positive correlation between oleic acid with gadoleic and lignoceric acid in both populations, while a negative correlation with other four fatty acids. Quantitative trait locus (QTL) analysis detected a total of 165 main-effects (M-QTLs) and 27 epistatic (E-QTLs) QTLs associated with these six minor fatty acids in both populations. Thirty four major QTLs (over 10% phenotype variance explained) mapped in five linkage groups and 28 clusters which has more than three QTLs identified in both populations. These results suggest that the major QTLs with large additive effects would play an important role in controlling these minor fatty acid composition in addition to oleic and linoleic acids in peanut oil. The interrelationship among these fatty acids should be considered when breeding for improvement of oil quality and fatty acid composition in term of consumer preference and health.

Technical Abstract: Peanut, a high-oil crop with about 50% oil content, is either crushed for oil or used as edible products. Fatty acid composition determines the oil quality which has high relevance to consumer health, flavor, and shelf life of commercial products. In addition to the major fatty acids, oleic acid (C18:1) and linoleic acid (C18:2) accounting for about 80% of peanut oil, the six other fatty acids, palmitic acid (C16:0), stearic acid (C18:0), arachidic acid (C20:0), gadoleic acid (C20:1), behenic acid (C22:0), and lignoceric acid (C24:0) are accounted for the rest 20%. To determine the genetic basis and to increase further understanding on effect of FAD2 genes on these fatty acids, two recombinant inbred line (RIL) populations namely S-population (high oleic line SunOleic 97R with recessive alleles of both FAD2A and FAD2B genes × low oleic line NC94022) and T-population (Tifrunner with recessive alleles of FAD2A gene × low oleic line GT-C20) were developed and used for identification of quantitative trait loci (QTLs). There was a significantly positive correlation between oleic acid with gadoleic and lignoceric acid in both populations, while a negative correlation with remaining four fatty acids. QTL analysis detected a total of 165 main-effects (M-QTLs) and 27 epistatic (E-QTLs) QTLs associated with these minor fatty acids in both populations with the phenotypic variation explained (PVE) ranging from 0.16% to 40.56%. Thirty four major QTLs (over 10% of PVE) mapped in five linkage groups and 28 clusters with > three QTLs were also identified in both the RILs. These results suggest that the major QTLs with large additive effects would play an important role in controlling these minor fatty acid composition in addition to oleic and linoleic acids in peanut oil. The interrelationship among these fatty acids should be considered when breeding for improvement of oil quality and fatty acid composition in term of consumer preference and health.