A novel soybean transcription factor, DREB7, regulates RD29A and SODFe gene expression in transgenic tobacco plants.

Glycinemax dehydration–responsive element binding (GmDREB) protein is a group of transcription factors that regulate the expression of several downstream genes that respond to abiotic stresses. Among the Glycine max DREB subfamily genes, the role and relationship of GmDREB7 to functional genes that respond to abiotic stresses are also unknown. In this study, the GmDREB7 gene of G. max was analyzed for expression, determining the relationship with two functional genes, NtRD29A and NtSODFe, in Nicotiana tabacum under normal (non-treated) and saline stress conditions daily for 3 wk (NaCl-treated). The 35S-GmDREB7-c-MYC construct was generated and transformed to produce transgenic N. tabacum plants. Three GmDREB7 transgenic N. tabacum lines L27, L42, and L50 were analyzed for their expression at the transcriptional level. Under non-treated and NaCl-treated conditions, the transcript level of the GmDREB7 gene was strongly expressed in all three transformed lines and was strongest in the L42 line. Under non-treated conditions, the L42 line had the strongest GmDREB7 gene expression level, which was 6.88 times higher than that of the L27 line and 12.17 times higher than that of the L50 line. Under NaCl-treated conditions, it was 2.73 times higher than that of the L27 line and 2.53 times higher than that of the L50 line. The results of investigating the relationship between the GmDREB7 gene of G. max and some genes that respond to abiotic stress in N. tabacum plants showed that overexpression of the GmDREB7 gene under NaCl-treated conditions reduced the level of transcription of NtRD29A and NtSODFe. This result is a new finding representing a difference from other soybean DREB genes. Therefore, it is necessary to expand research to determine the regulatory role of the GmDREB7 gene and other abiotic stress response genes to serve as a basis for using the GmDREB7 gene as a candidate in a strategy to improve tolerance to abiotic stress in crops. [ABSTRACT FROM AUTHOR]