Soybean Trihelix transcription factors GmGT-2A and GmGT-2B improve plant tolerance to abiotic stresses in transgenic Arabidopsis.
BACKGROUND
Trihelix transcription factors play important roles in light-regulated responses and other developmental processes. However, their functions in abiotic stress response are largely unclear. In this study, we identified two trihelix transcription factor genes GmGT-2A and GmGT-2B from soybean and further characterized their roles in abiotic stress tolerance.


RESULTS
Both genes can be induced by various abiotic stresses, and the encoded proteins were localized in nuclear region. In yeast assay, GmGT-2B but not GmGT-2A exhibits ability of transcriptional activation and dimerization. The N-terminal peptide of 153 residues in GmGT-2B was the minimal activation domain and the middle region between the two trihelices mediated the dimerization of the GmGT-2B. Transactivation activity of the GmGT-2B was also confirmed in plant cells. DNA binding analysis using yeast one-hybrid assay revealed that GmGT-2A could bind to GT-1bx, GT-2bx, mGT-2bx-2 and D1 whereas GmGT-2B could bind to the latter three elements. Overexpression of the GmGT-2A and GmGT-2B improved plant tolerance to salt, freezing and drought stress in transgenic Arabidopsis plants. Moreover, GmGT-2B-transgenic plants had more green seedlings compared to Col-0 under ABA treatment. Many stress-responsive genes were altered in GmGT-2A- and GmGT-2B-transgenic plants.


CONCLUSIONS
These results indicate that GmGT-2A and GmGT-2B confer stress tolerance through regulation of a common set of genes and specific sets of genes. GmGT-2B also affects ABA sensitivity.
Xie
Zong-Ming
ZM
National Key Laboratory of Plant Genomics, Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
Zou
Hong-Feng
HF
Lei
Gang
G
Wei
Wei
W
Zhou
Qi-Yun
QY
Niu
Can-Fang
CF
Liao
Yong
Y
Tian
Ai-Guo
AG
Ma
Biao
B
Zhang
Wan-Ke
WK
Zhang
Jin-Song
JS
Chen
Shou-Yi
SY
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics*; D019281:Dimerization; D055864:Droughts; D020224:Expressed Sequence Tags; D008957:Models, Genetic; D008969:Molecular Sequence Data; D030821:Plants, Genetically Modified; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013025:Glycine max / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques; D010940:Plant Proteins
D004268:DNA-Binding Proteins; D014157:Transcription Factors; C077393:rice nuclear protein GT-2; D010940:Plant Proteins