Promoter of Vegetable Soybean GmTIP1;6 Responds to Diverse Abiotic Stresses and Hormone Signals in Transgenic Arabidopsis

Tonoplast intrinsic proteins (TIPs), a sub-family of aquaporins (AQPs), are known to play important roles in plant abiotic stress responses. However, evidence for the promoters of TIPs involvement in abiotic stress processes remains scarce. In this study, the promoter of the vegetable soybean GmTIP1;6 gene, which had the highest similarity to TIP1-type AQPs from other plants, was cloned. Expression pattern analyses indicated that the GmTIP1;6 gene was dramatically induced by drought, salt, abscisic acid (ABA), and methyl jasmonate (MeJA) stimuli. Promoter analyses revealed that the GmTIP1;6 promoter contained drought, ABA, and MeJA cis-acting elements. Histochemical staining of the GmTIP1;6 promoter in transgenic Arabidopsis corroborated that it was strongly expressed in the vascular bundles of leaves, stems, and roots. Beta-glucuronidase (GUS) activity assays showed that the activities of the GmTIP1;6 promoter were enhanced by different concentrations of polyethylene glycol 6000 (PEG 6000), NaCl, ABA, and MEJA treatments. Integrating these results revealed that the GmTIP1;6 promoter could be applied for improving the tolerance to abiotic stresses of the transgenic plants by promoting the expression of vegetable soybean AQPs.

Automated summary

Tonoplast intrinsic proteins (TIPs) are a sub-family of aquaporins (AQPs) that play important roles in plant abiotic stress responses. In this study, the promoter of the GmTIP1;6 gene in vegetable soybean was cloned, and its expression pattern and promoter analyses revealed its involvement in drought, salt, abscisic acid (ABA), and methyl jasmonate (MeJA) stress processes. Histochemical staining and activity assays further confirmed the high expression and responsiveness of the GmTIP1;6 promoter to different abiotic stress treatments. Overall, the GmTIP1;6 promoter can be utilized to enhance the tolerance of transgenic plants to abiotic stresses by promoting the expression of vegetable soybean AQPs.