Cloning and functional analysis of drought-inducible promoter AhMYB44-11- Pro in peanut (Arachis hypogaea L.)

Drought is a significantly environmental factor that poses a serious threat to peanut yield and quality in China. Our study aims to elucidate the regulatory mechanism of the drought stress response gene AhMYB44-11 and uncover the function of its promoter. We isolated the promoter sequence AhMYB44-11-Pro from the peanut genome and constructed recombinant expression vectors comprising the full-length promoter and several 5'-terminal deletion promoters, each fused with the GUS reporter gene. These vectors were then introduced into plant tissue via Agrobacterium rhizogenes-mediated transformation to assess promoter activity and expression patterns. The results revealed that AhMYB44-11-Pro contains a higher number of drought-responsive cis-regulatory elements, including MBS and Myb-binding sites, compared to the promoter of its homologous gene AhMYB44-01. Furthermore, dehydration treatment significantly enhanced GUS staining and activity in AhMYB44-11-Pro transgenic Arabidopsis, indicating that the promoter’s activity is upregulated under drought stress. These findings confirm that AhMYB44-11-Pro functions as a drought-inducible promoter. Additionally, AhMYB44-11-Pro contains a seed endosperm-specific expression element and gibberellin response elements, demonstrating an increased expression trend during pod development, as evidenced by GUS histochemical staining. This suggests that AhMYB44-11 may play a crucial role in seed development, particularly in dry matter accumulation. This research lays the groundwork for a comprehensive analysis of the biological functions of AhMYB44 and provides a valuable reference for genetically enhancing crop drought resistance.