Aquaporins (AQPs) significantly impact the regulation of water transport and can modulate traits related to tolerance to abiotic stress. Our previous study confirmed that SbTIP2;1 is expressed in response to abiotic stress conditions in sorghum. This study examined the role of the SbTIP2;1 gene in transgenic tobacco plants. The SbTIP2;1 gene has been cloned into the Gateway-compatible plant expression vector pMDC100, driven by the CaMV35S promoter, and subsequently transferred into tobacco plants using the leaf-disc method. Tobacco plants expressing the SbTIP2;1 gene were propagated to the T2 generation and exposed to increasing drought, salinity, heat, and cold stresses. Water use traits, including transpiration, canopy temperature (CT), canopy temperature difference (CTD), and expression profiles, showed significant differences among transgenic tobacco events and wild-type (WT) plants under abiotic stress treatments. Overexpression of the SbTIP2;1 AQP gene in roots and leaves showed that transgenic plants regulate transpiration differently than WT under drought and heat stress, enabling more water conservation and/or better leaf cooling. Transgenics showed cooler canopy temperature (CT) and higher canopy temperature depression (CTD) compared to WT, along with significant upregulation of SbTIP2;1 under stress, underscoring its role in improving adaptation to drought and heat. Therefore, the sorghum AQP gene SbTIP2;1 may serve as a promising candidate for enhancing abiotic stress tolerance in crops.

