Genome-Wide Analysis of Tritipyrum HSFs and Functional Characterization of TtHSF97 for Salt Tolerance

Soil salinization is a major abiotic stress constraining global agricultural production. In this study, a genome-wide analysis of the salt-tolerant hybrid germplasm Tritipyrum identified 103 heat shock transcription factors (TtHSF) genes, which were classified into three major groups (A, B, and C) and shared conserved motifs. Transcriptome data and qRT-PCR revealed that 29 of the TtHSF genes exhibited high expression levels in response to salt stress and recovery. Notably, TtHSF97, localized on Tel5E01T611500, exhibited significantly upregulated expression under salt stress. Subcellular localization confirmed that TtHSF97 is a nuclear-enriched protein, consistent with its function as a transcription factor. Heterologous overexpression of TtHSF97 in Arabidopsis significantly enhanced salt tolerance of transgenic plants, enabling them to maintain a high leaf expansion rate and root length under 150 mM NaCl stress. Correlation analysis identified 733 genes positively correlated with TtHSF97 expression, which are involved in metabolism, cellular processes, and stress responses. This study provides crucial genetic resources for improving the salt tolerance in major food crops through molecular breeding. The development of salt-tolerant wheat varieties using TtHSF97 will directly enhance crop productivity and ecological adaptability in saline soils, with significant application value for ensuring food security and promoting sustainable agricultural development. The results of this study demonstrate that transcription factor engineering is an effective strategy for improving crop stress resistance.