title: Natural variations in stearoyl-acp desaturase genes affect the conversion of stearic to oleic acid in maize kernel.
abstract: We identified 11 SAD genes, and mined their natural variations associated with the conservation of stearic to oleic acid, especially ZmSAD1 supported by both the QTL and an expression QTL. Maize oil is generally regarded as a healthy vegetable oil owing to its low abundance of saturated fatty acids. Stearoyl-ACP desaturase (SAD) is a key rate-limiting enzyme for the conservation of stearic (C18:0) to oleic (C18:1) acid. Here, 11 maize SAD genes were identified to have more divergent functions than Arabidopsis SAD genes. The genomic regional associations in a maize panel including 508 inbred lines identified 6 SAD genes significantly associated (P < 0.01) with the C18:0/C18:1 ratio or the level of C18:0 or C18:1, one gene of which co-localized with a quantitative trait locus (QTL) and 5 of which co-localized with an expression QTL. ZmSAD1, supported by both the QTL and an expression QTL, had the largest effect on C18:0/C18:1. One nonsynonymous single-nucleotide polymorphism in exon 3 and one 5-bp insertion/deletion in the 3' untranslated region were further shown to contribute to the natural variation in C18:0/C18:1 according to ZmSAD1-based association mapping. Finally, selection tests of ZmSAD1 in teosinte, regular maize, and high-oil maize indicated that ZmSAD1 was not a selection target during the process of maize domestication and high-oil maize development. These results will guide the manipulation of the ratio between saturated and unsaturated fatty acids in maize.
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement, National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China.
authors.forename: Yingjia
authors.initials: Y
authors.lastname: Han
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement, National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China.
authors.forename: Gen
authors.initials: G
authors.lastname: Xu
authors.affiliation: College of Life Science, Yangtze University, Jingzhou, 434025, Hubei, China.
authors.forename: Hewei
authors.initials: H
authors.lastname: Du
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement, National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China.
authors.forename: Jieyun
authors.initials: J
authors.lastname: Hu
authors.affiliation: Shandong Cotton Research Center, Shandong Academy of Agricutural Sciences, Jinan, 250100, China.
authors.forename: Zhanji
authors.initials: Z
authors.lastname: Liu
authors.affiliation: School of Biological Science and Technology, University of Jinan, Jinan, 250022, Shandong, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement, National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China.
authors.forename: Jiansheng
authors.initials: J
authors.lastname: Li
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement, National Maize Improvement Center of China, China Agricultural University, Beijing, 100193, China. redyx2005@126.com.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Yang
mesh_terms: D000483:Alleles; D003314:Corn Oil / Q000737:chemistry; D018744:DNA, Plant / Q000235:genetics; D044943:Fatty Acid Desaturases / Q000235:genetics*; D005838:Genotype; D005810:Multigene Family; D019301:Oleic Acid / Q000737:chemistry*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics*; D040641:Quantitative Trait Loci; D012639:Seeds / Q000737:chemistry; D017422:Sequence Analysis, DNA; D013229:Stearic Acids / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry / Q000235:genetics*
chemical_list: D018744:DNA, Plant; D010940:Plant Proteins; D013229:Stearic Acids; D019301:Oleic Acid; C031183:stearic acid; D003314:Corn Oil; D044943:Fatty Acid Desaturases