title: Overexpression of AtDREB1A causes a severe dwarf phenotype by decreasing endogenous gibberellin levels in soybean [Glycine max (L.) Merr].
abstract: Gibberellic acids (GAs) are plant hormones that play fundamental roles in plant growth and developmental processes. Previous studies have demonstrated that three key enzymes of GA20ox, GA3ox, and GA2ox are involved in GA biosynthesis. In this study, the Arabidopsis DREB1A gene driven by the CaMV 35S promoter was introduced into soybean plants by Agrobacterium- mediated transformation. The results showed that the transgenic soybean plants exhibited a typical phenotype of GA-deficient mutants, such as severe dwarfism, small and dark-green leaves, and late flowering compared to those of the non-transgenic plants. The dwarfism phenotype was rescued by the application of exogenous GA(3) once a week for three weeks with the concentrations of 144 µM or three times in one week with the concentrations of 60 µM. Quantitative RT-PCR analysis revealed that the transcription levels of the GA synthase genes were higher in the transgenic soybean plants than those in controls, whereas GA-deactivated genes except GmGA2ox4 showed lower levels of expression. The transcript level of GmGA2ox4 encoding the only deactivation enzyme using C(20)-GAs as the substrates in soybean was dramatically enhanced in transgenic plants compared to that of wide type. Furthermore, the contents of endogenous bioactive GAs were significantly decreased in transgenic plants than those of wide type. The results suggested that AtDREB1A could cause dwarfism mediated by GA biosynthesis pathway in soybean.
authors.affiliation: The Guangdong Subcenter of National Center for Soybean Improvement, State Key Laboratory of Agricultural and Biological Resources Protection and Utilization in Subtropics, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, P. R. China.
authors.forename: Haicui
authors.initials: H
authors.lastname: Suo
authors.forename: Qibin
authors.initials: Q
authors.lastname: Ma
authors.forename: Kaixin
authors.initials: K
authors.lastname: Ye
authors.forename: Cunyi
authors.initials: C
authors.lastname: Yang
authors.forename: Yujuan
authors.initials: Y
authors.lastname: Tang
authors.forename: Juan
authors.initials: J
authors.lastname: Hao
authors.forename: Zhanyuan J
authors.initials: ZJ
authors.lastname: Zhang
authors.forename: Mingluan
authors.initials: M
authors.lastname: Chen
authors.forename: Yuqi
authors.initials: Y
authors.lastname: Feng
authors.forename: Hai
authors.initials: H
authors.lastname: Nian
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics*; D004392:Dwarfism / Q000235:genetics*; D015870:Gene Expression; D005875:Gibberellins / Q000378:metabolism* / Q000494:pharmacology; D010641:Phenotype; D018515:Plant Leaves / Q000033:anatomy & histology / Q000187:drug effects; D030821:Plants, Genetically Modified; D012639:Seeds / Q000033:anatomy & histology / Q000187:drug effects; D013025:Glycine max / Q000033:anatomy & histology / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; C114578:DREB1A protein, Arabidopsis; D005875:Gibberellins; D014157:Transcription Factors; C007842:gibberellic acid