MsABCG1, ATP-Binding Cassette G transporter from Medicago Sativa, improves drought tolerance in transgenic Nicotiana Tabacum.

Drought has a devastating impact, presenting a formidable challenge to agricultural productivity and global food security. Among the numerous ABC transporter proteins found in plants, the ABCG transporters play a crucial role in plant responses to abiotic stress. In Medicago sativa, the function of ABCG transporters remains elusive. Here, we report that MsABCG1, a WBC-type transporter highly conserved in legumes, is critical for the response to drought in alfalfa. MsABCG1 is localized on the plasma membrane, with the highest expression observed in roots under normal conditions, and its expression is induced by drought, NaCl and ABA signalling. In transgenic tobacco, overexpression of MsABCG1 enhanced drought tolerance, evidenced by increased osmotic regulatory substances and reduced lipid peroxidation. Additionally, drought stress resulted in reduced ABA accumulation in tobacco overexpressing MsABCG1, demonstrating that overexpression of MsABCG1 enhanced drought tolerance was not via an ABA-dependent pathway. Furthermore, transgenic tobacco exhibited increased stomatal density and reduced stomatal aperture under drought stress, indicating that MsABCG1 has the potential to participate in stomatal regulation during drought stress. In summary, these findings suggest that MsABCG1 significantly enhances drought tolerance in plants and provides a foundation for developing efficient drought-resistance strategies in crops.