Variation in seed fatty acid composition and sequence divergence in the FAD2 gene coding region between wild and cultivated sesame.
Sesame germplasm harbors genetic diversity which can be useful for sesame improvement in breeding programs. Seven accessions with different levels of oleic acid were selected from the entire USDA sesame germplasm collection (1232 accessions) and planted for morphological observation and re-examination of fatty acid composition. The coding region of the FAD2 gene for fatty acid desaturase (FAD) in these accessions was also sequenced. Cultivated sesame accessions flowered and matured earlier than the wild species. The cultivated sesame seeds contained a significantly higher percentage of oleic acid (40.4%) than the seeds of the wild species (26.1%). Nucleotide polymorphisms were identified in the FAD2 gene coding region between wild and cultivated species. Some nucleotide polymorphisms led to amino acid changes, one of which was located in the enzyme active site and may contribute to the altered fatty acid composition. Based on the morphology observation, chemical analysis, and sequence analysis, it was determined that two accessions were misnamed and need to be reclassified. The results obtained from this study are useful for sesame improvement in molecular breeding programs.
Department of Crop and Soil Sciences, University of Georgia , Griffin, Georgia 30223, United States.
Zhenbang
Z
Chen
Brandon
B
Tonnis
Brad
B
Morris
Richard B
RB
Wang
Amy L
AL
Zhang
David
D
Pinnow
Ming Li
ML
Wang
D000595:Amino Acid Sequence; D019143:Evolution, Molecular; D044943:Fatty Acid Desaturases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005227:Fatty Acids / Q000737:chemistry* / Q000378:metabolism; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012639:Seeds / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D031685:Sesamum / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
D005227:Fatty Acids; D010940:Plant Proteins; D044943:Fatty Acid Desaturases
fatty acid composition; gene for fatty acid desaturase (FAD2); nucleotide diversity; sesame