title: Characterization of theFAD2Gene Family in Soybean Reveals the Limitations of Gel-Based TILLING in Genes with High Copy Number.
abstract: Soybean seed oil typically contains 18-20% oleic acid. Increasing the content of oleic acid is beneficial for health and biodiesel production. Mutations inFAD2-1genes have been reported to increase seed oleic acid content. A subset of 1,037 mutant families from a mutagenized soybean cultivar (cv.) Forrest population was screened using reverse genetics (TILLING) to identify mutations withinFAD2genes. Although nofad2mutants were identified using gel-based TILLING, fourfad2-1Aand onefad2-1Bmutants were identified to have high seed oleic acid content using forward genetic screening and subsequent target sequencing. TILLING has been successfully used as a non-transgenic reverse genetic approach to identify mutations in genes controlling important agronomic traits. However, this technique presents limitations in traits such as oil composition due to gene copy number and similarities within the soybean genome. In soybean,FAD2are present as two copies,FAD2-1andFAD2-2. Two FAD2-1members: FAD2-1A and FAD2-1B; and threeFAD2-2members:FAD2-2A, FAD2-2B, andFAD2-2Chave been reported. Syntenic, phylogenetic, andin silicoanalysis revealed two additional members constituting theFAD2gene family:GmFAD2-2DandGmFAD2-2E, located on chromosomes 09 and 15, respectively. They are presumed to have diverged from otherFAD2-2members localized on chromosomes 19 (GmFAD2-2AandGmFAD2-2B) and 03 (GmFAD2-2C). This work discusses alternative solutions to the limitations of gel-based TILLING in functional genomics due to high copy number and multiple paralogs of theFAD2gene family in soybean.
authors.affiliation: Department of Plant, Soil and Agricultural Systems, Southern Illinois University Carbondale, IL, USA.
authors.forename: Naoufal
authors.initials: N
authors.lastname: Lakhssassi
authors.affiliation: Department of Plant, Soil and Agricultural Systems, Southern Illinois University Carbondale, IL, USA.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Department of Plant, Soil and Agricultural Systems, Southern Illinois University Carbondale, IL, USA.
authors.forename: Shiming
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Plant, Soil and Agricultural Systems, Southern Illinois University Carbondale, IL, USA.
authors.forename: Vincent
authors.initials: V
authors.lastname: Colantonio
authors.affiliation: Department of Animal Science, Food and Nutrition, Southern Illinois University Carbondale, IL, USA.
authors.forename: Amer
authors.initials: A
authors.lastname: AbuGhazaleh
authors.affiliation: Department of Plant, Soil and Agricultural Systems, Southern Illinois University Carbondale, IL, USA.
authors.forename: Khalid
authors.initials: K
authors.lastname: Meksem
keywords: EMS mutagenesis; FAD2-1; FAD2-2; TILLING; forward genetics; mutation breeding; oleic acid; reverse genetics