A drought-inducible glutathione S-transferase gene (ScGSTF30) confers drought tolerance in sugarcane (Saccharum spp.)

• Genome-wide analysis identifies 115 GST genes in the complex sugarcane genome. • ScGSTF30 emerges as the most drought-responsive member. • ScGSTF30 overexpression exhibits improved antioxidant capacity and osmotic adjustment. • ScGSTF30 integrates hormonal signaling with oxidative stress defense pathways. • WRKY and ABF transcription factors coordinate ScGSTF30 -mediated drought defense networks. Drought stress severely constrains plant growth and development, posing a significant environmental challenge to agriculture. As a key protective enzyme, the glutathione S-transferase (GST) family plays a vital role in plant drought stress responses. However, systematic characterization and function of the GST gene in sugarcane ( Saccharum spp.) have not been conducted. Comprehensive characterization of the GST family in sugarcane revealed 115 ScGST genes. Under drought stress, ScGSTF30 expression was rapidly and sustainably induced in leaves, with a 22-fold upregulation observed during the 0∼72 h period. ScGSTF30 overexpression enhanced drought tolerance through the orchestration of a coordinated physiological response. Specifically, this response elevated proline levels by 56.6% and enhanced the activities of two key antioxidant enzymes, peroxidase (POD) and superoxide dismutase (SOD). Compared with the wild type (WT), this led to a significant reduction in malondialdehyde (MDA, 29.8%) and reactive oxygen species (ROS, 20.2%), providing effectively protection against oxidative damage . Further transcriptomic analysis provided evidence that ScGSTF30 mediates a coordinated stress adaptation mechanism. Specifically, this mechanism features the elevated expression of genes associated with the antioxidant system (i.e., ScPOD, ScSOD, ScAPX ) and proline biosynthesis pathway (i.e., ScP5CR, ScP5CS ), accompanied by the reorganization of key phytohormone signaling pathways (including ScPP2C, ScSNRK2, ScABF ). In summary, ScGSTF30 acts as a key regulator that integrates antioxidant defense, osmotic adjustment, and hormone signaling, and thus it provides a valuable genetic resource and mechanistic insights for drought tolerance improvement in sugarcane.