title: The soybean stem growth habit gene Dt1 is an ortholog of Arabidopsis TERMINAL FLOWER1.
abstract: Classical genetic analysis has revealed that the determinate habit of soybean (Glycine max) is controlled by a recessive allele at the determinate stem (Dt1) locus. To dissect the molecular basis of the determinate habit, we isolated two orthologs of pea (Pisum sativum) TERMINAL FLOWER1a, GmTFL1a and GmTFL1b, from the soybean genome. Mapping analysis indicated that GmTFL1b is a candidate for Dt1. Despite their high amino acid identity, the two genes had different transcriptional profiles. GmTFL1b was expressed in the root and shoot apical meristems (SAMs), whereas GmTFL1a was mainly expressed in immature seed. The GmTFL1b transcript accumulated in the SAMs during early vegetative growth in both the determinate and indeterminate lines but thereafter was abruptly lost in the determinate line. Introduction of the genomic region of GmTFL1b from the indeterminate line complemented the stem growth habit in the determinate line: more nodes were produced, and flowering in the terminal raceme was delayed. The identity between Dt1 and GmTFL1b was also confirmed with a virus-induced gene silencing experiment. Taken together, our data suggest that Dt1 encodes the GmTFL1b protein and that the stem growth habit is determined by the variation of this gene. The dt1 allele may condition the determinate habit via the earlier loss in GmTFL1b expression concomitant with floral induction, although it functions normally under the noninductive phase of flowering. An association test of DNA polymorphisms with the stem growth habit among 16 cultivars suggested that a single amino acid substitution in exon 4 determines the fate of the SAM after floral induction.
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150040, China.
authors.forename: Baohui
authors.initials: B
authors.lastname: Liu
authors.forename: Satoshi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Tomoo
authors.initials: T
authors.lastname: Uchiyama
authors.forename: Fanjiang
authors.initials: F
authors.lastname: Kong
authors.forename: Akira
authors.initials: A
authors.lastname: Kanazawa
authors.forename: Zhengjun
authors.initials: Z
authors.lastname: Xia
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nagamatsu
authors.forename: Maiko
authors.initials: M
authors.lastname: Arai
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamada
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kitamura
authors.forename: Chikara
authors.initials: C
authors.lastname: Masuta
authors.forename: Kyuya
authors.initials: K
authors.lastname: Harada
authors.forename: Jun
authors.initials: J
authors.lastname: Abe
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics; D002874:Chromosome Mapping; D015870:Gene Expression; D020868:Gene Silencing; D008969:Molecular Sequence Data; D018547:Plant Stems / Q000254:growth & development*; D011110:Polymorphism, Genetic; D013025:Glycine max / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C102864:TFL1 protein, Arabidopsis