title: Identification and Molecular Analysis of Four New Alleles at the W1 Locus Associated with Flower Color in Soybean.
abstract: In soybean, flavonoid 3'5'-hydroxylase (F3'5'H) and dihydroflavonol-4-reductase (DFR) play a crucial role in the production of anthocyanin pigments. Loss-of-function of the W1 locus, which encodes the former, or W3 and W4, which encode the latter, always produces white flowers. In this study, we searched for new genetic components responsible for the production of white flowers in soybean and isolated four white-flowered mutant lines, i.e., two Glycine soja accessions (CW12700 and CW13381) and two EMS-induced mutants of Glycine max (PE1837 and PE636). F3'5'H expression in CW12700, PE1837, and PE636 was normal, whereas that in CW13381 was aberrant and missing the third exon. Sequence analysis of F3'5'H of CW13381 revealed the presence of an indel (~90-bp AT-repeat) in the second intron. In addition, the F3'5'H of CW12700, PE1837, and PE636 harbored unique single-nucleotide substitutions. The single nucleotide polymorphisms resulted in substitutions of amino acid residues located in or near the SRS4 domain of F3'5'H, which is essential for substrate recognition. 3D structure modeling of F3'5'H indicated that the substitutions could interfere with an interaction between the substrate and heme group and compromise the conformation of the active site of F3'5'H. Recombination analysis revealed a tight correlation between all of the mutant alleles at the W1 locus and white flower color. On the basis of the characterization of the new mutant alleles, we discussed the biological implications of F3'5'H and DFR in the determination of flower colors in soybean.
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea.
authors.forename: Jagadeesh
authors.initials: J
authors.lastname: Sundaramoorthy
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea.
authors.forename: Gyu Tae
authors.initials: GT
authors.lastname: Park
authors.affiliation: Department of Biology Education, Kyungpook National University, Daegu, Republic of Korea.
authors.forename: Jeong Ho
authors.initials: JH
authors.lastname: Chang
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea.
authors.forename: Jeong-Dong
authors.initials: JD
authors.lastname: Lee
authors.affiliation: Department of Biology, Kyungpook National University, Daegu, Republic of Korea.
authors.forename: Jeong Hoe
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Plant Bioscience, Seoul National University, Seoul, Republic of Korea.
authors.forename: Hak Soo
authors.initials: HS
authors.lastname: Seo
authors.affiliation: Department of Biotechnology, Chonnam National University, Chonnam, Republic of Korea.
authors.forename: Gyuhwa
authors.initials: G
authors.lastname: Chung
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea.
authors.forename: Jong Tae
authors.initials: JT
authors.lastname: Song
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000872:Anthocyanins / Q000378:metabolism; D035264:Flowers; D020869:Gene Expression Profiling; D023061:Gene Order; D008958:Models, Molecular; D009154:Mutation; D010641:Phenotype; D010860:Pigments, Biological; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics; D011487:Protein Conformation; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable; D013025:Glycine max / Q000235:genetics* / Q000378:metabolism
chemical_list: D000872:Anthocyanins; D010860:Pigments, Biological; D010940:Plant Proteins