Harnessing the power of mangrove genetics: AMDREP8 promoter enhances salt stress tolerance in plants

Mangroves are halophytes and the only plant systems capable of thriving in extreme environments. However, their salt tolerance mechanisms remain insufficiently explored. We investigated the salt tolerance mechanism of Avicennia marina by analyzing its endogenous promoters. We developed a salt-tolerant promoter, AMDREP8, which contains a DRE element linked to the salt stress response. Transient expression in tobacco validated its function. AMDREP8 regulates exogenous gene expression in both dicotyledons (Solanum tuberosum, Pachyrhizus erosus and Nicotiana tabacum) and monocotyledons (Cocos nucifera, Thalassia hemprichii, and Agropyron cristatum). GUS expression in tobacco regulated by AMDREP8 was 5.05 times higher than that regulated by the 35 S promoter. AMDREP8 enhanced salt tolerance in Saccharomyces cerevisiae by promoting heterologous expression of the salt tolerance gene AmBADH. The average colony area of transgenic yeast grown under salt stress for 3 days was 1.47 times that of the control regulated by the GAL1 promoter. Additionally, regulation of AmBADH expression by AMDREP8 improved salt tolerance in Arabidopsis. After 8 days of salt stress, the average root length of transgenic Arabidopsis was 1.49 times that of the control. After 20 days, the average plant height was 1.52 times greater than that of the control. AMDREP8 offers a promising tool for plant genetic engineering.