Heat Shock Factor 8 Introducing into Soybean ( Glycine max ) by Agrobacterium -Mediated Transformation

Environmental stress seriously affects growth and development of crops. Heat shock transcription factor (heat shock factor 8, HSF8 ) is a class of proteins that play important roles in the reactions of heat shock, the main functions of heat shock gene are binding the corresponding heat shock element in the process of expression, initiating the gene transcription process and, ultimately, facilitating the expression of heat shock protein (HSP) gene. In this paper, we inserted hsf8 gene into dicotyledon expression vector pCAMBIA3300 that contains the selection marker, bar gene. The construct, named pCAMBIA3300- HSF8 , has been transfered into new soybean lines, Hajiao5337 and Hajiao5489, mediated by Agrobacterium tumefaciens . In the practice of soybean genetic transformation, we explored the impact factors on the transformation of soybean cotyledon mediated by Agrobacterium , and optimized the transformation conditions. It is the way to increase the selection efficiency by delaying the screening after co-culture with optimal concentration of glufosinate-ammonium 3.5 mg/L in selection culture medium. We obtained the T1 generation transgenic plants with pCAMBIA3300- HSF8 by Agrobacterium -mediated aprroch derived from Hajiao5337 and Hajiao5489 , of which 17 plants were proved by PCR to be positive transgenic plants. Furthermore, transcription level of hsf8 gene in T1 transgenic plants with glufosinate-ammonium resistance was detected by Real-time PCR approach, the results showed that 9 of 17 plants had much higher expression level than that of the reference of Hajiao5337, whereas one transgenic plant had lower level than that of another reference Hajiao5489.