Identification of the SFT2 Gene Family in Wheat (Triticum aestivum) and Preliminary Functional Investigation Under Cadmium Stress
WU Liu-Liu1,2, TANG Ming-Ming2, SUN Jun-Yan1,2, DONG Li-Ping1,2, LI Shu-Mei1,2, LIU Shu-Han1,2, TONG Sheng-Li1,2, YANG Yan-Lin1,2, CHU Zong-Li1,2*
1 College of Agronomy, Xinyang Agriculture and Forestry University, Xinyang 464000, China; 2 Xinyang Key Laboratory of Wheat Cultivation and Ecophysiology/Xinyang Engineering Research Center for Soil Pollution Prevention and Control/Xinyang Key Laboratory of Crop Seed Innovation, Xinyang 464000, China
Abstract：The vesicle transport protein (SFT2) gene family plays a key role in membrane trafficking and stress responses in eukaryotes. However, its members in wheat (Triticum aestivum) and their functions under cadmium (Cd) stress remain unclear. This study performed a genome-wide identification of the SFT2 family in wheat, with focus on the biological function of TaSFT2 in Cd stress response. Results showed that 21 TaSFT2 members were identified in the wheat genome, distributed across 15 chromosomes and relatively evenly among the A, B, and D subgenomes. Phylogenetic analysis classified SFT2 proteins from wheat, maize (Zea mays), and Arabidopsis thaliana into 4 groups, with wheat TaSFT2s mainly clustered in groups D, indicating functional divergence during evolution. Gene structure and conserved motif analyses revealed similar structural characteristics among homologous genes, with all members containing 4~5 introns. Cis-acting element analysis identified multiple hormone-responsive elements (methyl jasmonate, abscisic acid) and abiotic stress-responsive elements (drought, low temperature, anoxia) in TaSFT2 promoters, suggesting their broad involvement in hormone signaling and stress responses. Expression profiling demonstrated tissue and development stage-specific expression patterns of TaSFT2s, with some members showing significant expression in spikes and roots, implying potential roles in spike development and root function, respectively. Heterologous expression assays confirmed that TaSFT2-1 overexpression significantly enhanced Cd stress tolerance in Escherichia coli. This study elucidated the member composition, evolutionary characteristics, and expression patterns of the wheat SFT2 gene family, as well as the biological function of TaSFT2-1 in response to Cd stress. These findings provide a theoretical basis and genetic resources for dissecting the mechanisms underlying heavy metal tolerance in wheat and for developing Cd-tolerant germplasm.
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