Promoter cloning and expression analysis of transcription factor gene gmmyb92 in soybean (Glycine max. L)

Abstract

MYB transcription factors in plant play a critical role in regulating response to abiotic stress or adverse environments. In our previous study, DGEP data revealed GmMYB92 is involved in soybean tolerance to abiotic stress. Here, we analyzed the spatial and temporal expression of GmMYB92 and found GmMYB92 mainly expressed in roots, young stem and flower tissues during the whole growth stages, and significantly induced by ABA, salt, low temperature (4°C) and PEG6000 (drought) treatments, and the time points for induction expression varied among different treatments. Bioinformatic analysis of GmMYB92 promoter region contained many stress-related cis-elements, such as, HSE for heat stress, ARE for anaerobic induction, TC-rich repeat element for defense and stress responsiveness and a CAT-box for specific-expression element in meristem expression. Hereafter, the GmMYB92 promoter region with a 1,951bp DNA fragment including start codon was cloned to drive GUS gene expression to form a chimeric expression cassette used for Arabidopsis Thaliana transformation by means of floral dip. GUS histochemical staining was conducted to characterize the GmMYB92 promoter activity in different tissues including root, stem, leaf, flower and pod from transgenic Arabidopsis Thaliana. The results showed that the gus gene under the control of GmMYB92 promoter mainly expressed in root, young stem and flower, which was consistent with the expression pattern in soybean plant. Our study supply a basis support to further insight into MYB transcription factor’s role in the complicated regulation network related to different genes and the mechanism in stress-resistance in plants.