title: Dt2 is a gain-of-function MADS-domain factor gene that specifies semideterminacy in soybean.
abstract: Similar to Arabidopsis thaliana, the wild soybeans (Glycine soja) and many cultivars exhibit indeterminate stem growth specified by the shoot identity gene Dt1, the functional counterpart of Arabidopsis TERMINAL FLOWER1 (TFL1). Mutations in TFL1 and Dt1 both result in the shoot apical meristem (SAM) switching from vegetative to reproductive state to initiate terminal flowering and thus produce determinate stems. A second soybean gene (Dt2) regulating stem growth was identified, which, in the presence of Dt1, produces semideterminate plants with terminal racemes similar to those observed in determinate plants. Here, we report positional cloning and characterization of Dt2, a dominant MADS domain factor gene classified into the APETALA1/SQUAMOSA (AP1/SQUA) subfamily that includes floral meristem (FM) identity genes AP1, FUL, and CAL in Arabidopsis. Unlike AP1, whose expression is limited to FMs in which the expression of TFL1 is repressed, Dt2 appears to repress the expression of Dt1 in the SAMs to promote early conversion of the SAMs into reproductive inflorescences. Given that Dt2 is not the gene most closely related to AP1 and that semideterminacy is rarely seen in wild soybeans, Dt2 appears to be a recent gain-of-function mutation, which has modified the genetic pathways determining the stem growth habit in soybean.
authors.affiliation: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Jieqing
authors.initials: J
authors.lastname: Ping
authors.affiliation: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Lianjun
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Meixia
authors.initials: M
authors.lastname: Zhao
authors.affiliation: Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Maoyun
authors.initials: M
authors.lastname: She
authors.affiliation: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Yi
authors.initials: Y
authors.lastname: Sui
authors.affiliation: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Feng
authors.initials: F
authors.lastname: Lin
authors.affiliation: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Zongxiang
authors.initials: Z
authors.lastname: Tang
authors.affiliation: Department of Agronomy and Horticulture/Center for Plant Science Innovation, University of Nebraska, Lincoln, Nebraska 68583.
authors.forename: Hanh
authors.initials: H
authors.lastname: Nguyen
authors.affiliation: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907.
authors.forename: Zhixi
authors.initials: Z
authors.lastname: Tian
authors.affiliation: Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Qiu
authors.affiliation: Soybean/Maize Germplasm, Pathology, and Genetics Research Unit, U.S. Department of Agriculture-Agricultural Research Service, Department of Crop Sciences, University of Illinois, Urbana, Illinois 61801.
authors.forename: Randall L
authors.initials: RL
authors.lastname: Nelson
authors.affiliation: Department of Agronomy and Horticulture/Center for Plant Science Innovation, University of Nebraska, Lincoln, Nebraska 68583.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Clemente
authors.affiliation: Department of Agronomy and Horticulture/Center for Plant Science Innovation, University of Nebraska, Lincoln, Nebraska 68583.
authors.forename: James E
authors.initials: JE
authors.lastname: Specht
authors.affiliation: Department of Agronomy, Purdue University, West Lafayette, Indiana 47907 maj@purdue.edu.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Ma
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D001483:Base Sequence; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics*; D035264:Flowers / Q000235:genetics / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D008040:Genetic Linkage; D056426:Genetic Loci; D026161:MADS Domain Proteins / Q000235:genetics* / Q000378:metabolism; D018519:Meristem / Q000235:genetics / Q000254:growth & development; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018547:Plant Stems / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified; D017422:Sequence Analysis, DNA; D013025:Glycine max / Q000235:genetics* / Q000254:growth & development
chemical_list: D026161:MADS Domain Proteins; D010940:Plant Proteins