title: The β-conglycinin deficiency in wild soybean is associated with the tail-to-tail inverted repeat of the α-subunit genes.
abstract: β-conglycinin, a major seed protein in soybean, is composed of α, α', and β subunits sharing a high homology among them. Despite its many health benefits, β-conglycinin has a lower amino acid score and lower functional gelling properties compared to glycinin, another major soybean seed protein. In addition, the α, α', and β subunits also contain major allergens. A wild soybean (Glycine soja Sieb et Zucc.) line, 'QT2', lacks all of the β-conglycinin subunits, and the deficiency is controlled by a single dominant gene, Scg-1 (Suppressor of β-conglycinin). This gene was characterized using a soybean cultivar 'Fukuyutaka', 'QY7-25', (its near-isogenic line carrying the Scg-1 gene), and the F₂ population derived from them. The physical map of the Scg-1 region covered by lambda phage genomic clones revealed that the two α-subunit genes, a β-subunit gene, and a pseudo α-subunit gene were closely organized. The two α-subunit genes were arranged in a tail-to-tail orientation, and the genes were separated by 197 bp in Scg-1 compared to 3.3 kb in the normal allele (scg-1). In addition, small RNA was detected in immature seeds of the mutants by northern blot analysis using an RNA probe of the α subunit. These results strongly suggest that β-conglycinin deficiency in QT2 is controlled by post-transcriptional gene silencing through the inverted repeat of the α subunits.
authors.affiliation: National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Tsubokura
authors.forename: Makita
authors.initials: M
authors.lastname: Hajika
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kanamori
authors.forename: Zhengjun
authors.initials: Z
authors.lastname: Xia
authors.forename: Satoshi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Akito
authors.initials: A
authors.lastname: Kaga
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Katayose
authors.forename: Masao
authors.initials: M
authors.lastname: Ishimoto
authors.forename: Kyuya
authors.initials: K
authors.lastname: Harada
mesh_terms: D052179:Antigens, Plant / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D002874:Chromosome Mapping; D018744:DNA, Plant / Q000235:genetics; D020440:Gene Duplication; D017343:Genes, Plant; D014644:Genetic Variation; D015698:Genomic Library; D005916:Globulins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D055029:Inverted Repeat Sequences; D008969:Molecular Sequence Data; D021122:Protein Subunits; D018749:RNA, Plant / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D055314:Seed Storage Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D030262:Soybean Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D013025:Glycine max / Q000235:genetics* / Q000378:metabolism*
chemical_list: D052179:Antigens, Plant; D018744:DNA, Plant; D005916:Globulins; D021122:Protein Subunits; D018749:RNA, Plant; D034741:RNA, Small Interfering; D055314:Seed Storage Proteins; D030262:Soybean Proteins; C013894:beta-conglycinin protein, Glycine max