Constitutive overexpression of GmDof17-1, a putative DOF transcription factor from soybean causing growth inhibition in tobacco

Abstract

The Dof proteins belong to a large family of plant transcription factors that share a single highly conserved zinc fi nger and play an important role in many physiological processes.To elucidate the function of Dof in soybean, GmDof17-1 was cloned from soybean (Glycine max (L.) Merr); the open reading frame (ORF) of GmDof17-1 is 846 bp and encodes a putative protein that includes 281 amino acids. Using qRT-PCR, the expression profi les of GmDof17-1 were obtained for various parts of the soybean plant. GmDof17-1 was primarily expressed in the roots and pods at various stages of pod development. The gene was ectopically expressed in tobacco under the control of the 2 × CaMV35S promoter to study the functions of the gene product.The transgenic tobacco plants showed to be dwarf, and the indole-3-acetic acid (IAA) content was decreased, whereas the sulfur-containing amino acid content of the seeds increased. These results provide new insight into the function of GmDof17-1 in seed development. IntroductionDof proteins are a major family of plant transcription factors that have a strongly conserved DNA-binding domain, which contains a single C 2 C 2 -type zinc-fi ngerlike motif that is generally located in the N-terminal region and a C-terminal domain for transcriptional regulation (this region has divergent amino acid sequences) (Yanagisawa and Izui, 1993;Yanagisawa, 2004). Since Dof1 (the fi rst identifi ed Dof protein) was found in maize (Yanagisawa and Izui, 1993), many Dof proteins have been discovered, which participate in specifi c biological processes in other plants. The functions of reported Dof genes are highly diverse and include roles in hormone response, defense response, organ development and other responses (Baumann et al., 1999;Kang and Singh, 2001; Kang et al., 2000;Kisu et al., 1998;Mena et al., 1998;Plesch et al., 2001;Vicente-Carbajosa et al., 1997;Wang et al., 2007;Ward et al., 2005;Washio, 2001;Xin et al., 2009;Yang et al., 2010).Phytohormones play important roles in coordinating many growth-related processes throughout the plant life cycle, including embryogenesis, vascular differentiation, organogenesis, tropic growth and root and shoot architecture (Kepinski, 2006;Quint and Gray, 2006; Shan et al., 2012 Stamm andKumar, 2010). Some researchers have studied the interactions between Dof proteins and phytohormones and the tobacco Dof protein NtBBF1 has been found to be involved in the auxin-inducible expression of rolB (Baumann et al., 1999).The expression of the pumpkin ascorbate oxidase gene (AOBP), which binds to the AGTA repeat through the Dof domain, is regulated by auxin (Kisu et al., 1998;Esaka et al., 1992). PtDof1 was isolated from Populus tomentosa, which exhibits tissue-specifi c expression (Xin et al., 2009). These studies indicate possible roles for Dof proteins in the auxin response. In Arabidopsis, OBP3 (AtDof3.6) was induced by salicylic acid (Kang et al., 2003), and OBP3 is a component in phytochrome and cryptochrome signaling. OBP3 mutants exhibit a root defect and yel...

Involvement of Auxin and Brassinosteroid in Dwarfism of Autotetraploid Apple (Malus × domestica)

“…The relationship between IAA content and stem height in transgenic plants was also reported. Overexpression of GmDof17-1 from soybean in tobacco plants caused a dwarf phenotype, and the IAA content was decreased 51 . Exogenous application of IAA could significantly promote plant elongation.…”