title: Expression of a putative dioxygenase gene adjacent to an insertion mutation is involved in the short internodes of columnar apples (Malus × domestica).
abstract: Determining the molecular mechanism of fruit tree architecture is important for tree management and fruit production. An apple mutant 'McIntosh Wijcik', which was discovered as a bud mutation from 'McIntosh', exhibits a columnar growth phenotype that is controlled by a single dominant gene, Co. In this study, the mutation and the Co gene were analyzed. Fine mapping narrowed the Co region to a 101 kb region. Sequence analysis of the Co region and the original wild-type co region identified an insertion mutation of an 8202 bp long terminal repeat (LTR) retroposon in the Co region. Segregation analysis using a DNA marker based on the insertion polymorphism showed that the LTR retroposon was closely associated with the columnar growth phenotype. RNA-seq and RT-PCR analysis identified a promising Co candidate gene (91071-gene) within the Co region that is specifically expressed in 'McIntosh Wijcik' but not in 'McIntosh'. The 91071-gene was located approximately 16 kb downstream of the insertion mutation and is predicted to encode a 2-oxoglutarate-dependent dioxygenase involved in an unknown reaction. Overexpression of the 91071-gene in transgenic tobaccos and apples resulted in phenotypes with short internodes, like columnar apples. These data suggested that the 8202 bp retroposon insertion in 'McIntosh Wijcik' is associated with the short internodes of the columnar growth phenotype via upregulated expression of the adjacent 91071-gene. Furthermore, the DNA marker based on the insertion polymorphism could be useful for the marker-assisted selection of columnar apples.
authors.affiliation: Apple Research Station, NARO Institute of Fruit Tree Science, Morioka, Iwate, 020-0123, Japan. okak@affrc.go.jp.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Okada
authors.affiliation: Apple Research Station, NARO Institute of Fruit Tree Science, Morioka, Iwate, 020-0123, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Wada
authors.affiliation: Apple Research Station, NARO Institute of Fruit Tree Science, Morioka, Iwate, 020-0123, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Moriya
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8634, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Katayose
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8634, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Fujisawa
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8634, Japan.
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Wu
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8634, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kanamori
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8634, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Kurita
authors.affiliation: Agrogenomics Research Center, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8634, Japan.
authors.forename: Harumi
authors.initials: H
authors.lastname: Sasaki
authors.affiliation: Okitsu Citrus Research Station, NARO Institute of Fruit Tree Science, Shimizu, Shizuoka, 424-0292, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fujii
authors.affiliation: NARO Institute of Fruit Tree Science, Tsukuba, Ibaraki, 305-8605, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Terakami
authors.affiliation: Apple Research Station, NARO Institute of Fruit Tree Science, Morioka, Iwate, 020-0123, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iwanami
authors.affiliation: NARO Institute of Fruit Tree Science, Tsukuba, Ibaraki, 305-8605, Japan.
authors.forename: Toshiya
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Apple Research Station, NARO Institute of Fruit Tree Science, Morioka, Iwate, 020-0123, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Abe
mesh_terms: D002874:Chromosome Mapping; D049308:Dioxygenases / Q000235:genetics* / Q000378:metabolism; D027845:Malus / Q000235:genetics* / Q000378:metabolism; D016254:Mutagenesis, Insertional / Q000235:genetics*; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018626:Retroelements / Q000235:genetics*; D017422:Sequence Analysis, DNA; D059467:Transcriptome / Q000235:genetics
chemical_list: D010940:Plant Proteins; D018626:Retroelements; D049308:Dioxygenases
keywords: 2-oxoglutarate-dependent dioxygenase; DNA marker; Mutant; RNA-seq; Retroposon; Tree architecture