A key methyltransferase, TaSAMT1, mediates wheat freezing tolerance by integrating brassinosteroid (BR) and salicylic acid (SA) signaling. TaSAMT1 converts SA to methyl SA (MeSA), enhancing freezing tolerance in wheat. Overexpression of TaSAMT1 increases MeSA levels and reduces SA, improving freezing tolerance, while its knockout reduces MeSA and increases SA, making plants more sensitive to freezing. MeSA application rescues freezing tolerance in TaSAMT1 mutants, but SA does not. BR signaling pathway component TaBZR1 directly binds to the TaSAMT1 promoter, inducing its transcription. TaBZR1 interacts with histone acetyltransferase TaHAG1, which enhances TaSAMT1 expression through increased histone acetylation and modulates the SA pathway during freezing stress. Overexpression of TaBZR1 or TaHAG1 alters TaSAMT1 expression and improves freezing tolerance. These findings reveal a key regulatory node connecting BR and SA pathways in plant cold stress response, providing targets for genetic improvement of freezing tolerance in crops. TaSAMT1-B is a salicylate carboxyl methyltransferase in wheat, with highest expression in seeds. It is induced by low temperatures and localizes to the cytoplasm. Recombinant TaSAMT1-B catalyzes SA methylation, converting it to MeSA, which contributes to cold response in wheat. Overexpression of TaSAMT1-B improves freezing tolerance, while knockout reduces it. TaSAMT1-B affects MeSA and SA accumulation under freezing stress, with higher MeSA levels in overexpression lines and lower in knockout lines. Exogenous MeSA application rescues freezing tolerance in TaSAMT1 mutants, but SA does not. TaBZR1 directly binds to the TaSAMT1 promoter, regulating its transcription. TaBZR1 interacts with TaHAG1, which enhances TaSAMT1 expression through histone acetylation. TaBZR1 and TaHAG1 cooperatively activate TaSAMT1 transcription, increasing histone acetylation and enhancing freezing tolerance. These findings highlight the role of TaSAMT1 and its regulatory factors in wheat freezing tolerance, providing insights for improving cold tolerance in crops.A key methyltransferase, TaSAMT1, mediates wheat freezing tolerance by integrating brassinosteroid (BR) and salicylic acid (SA) signaling. TaSAMT1 converts SA to methyl SA (MeSA), enhancing freezing tolerance in wheat. Overexpression of TaSAMT1 increases MeSA levels and reduces SA, improving freezing tolerance, while its knockout reduces MeSA and increases SA, making plants more sensitive to freezing. MeSA application rescues freezing tolerance in TaSAMT1 mutants, but SA does not. BR signaling pathway component TaBZR1 directly binds to the TaSAMT1 promoter, inducing its transcription. TaBZR1 interacts with histone acetyltransferase TaHAG1, which enhances TaSAMT1 expression through increased histone acetylation and modulates the SA pathway during freezing stress. Overexpression of TaBZR1 or TaHAG1 alters TaSAMT1 expression and improves freezing tolerance. These findings reveal a key regulatory node connecting BR and SA pathways in plant cold stress response, providing targets for genetic improvement of freezing tolerance in crops. TaSAMT1-B is a salicylate carboxyl methyltransferase in wheat, with highest expression in seeds. It is induced by low temperatures and localizes to the cytoplasm. Recombinant TaSAMT1-B catalyzes SA methylation, converting it to MeSA, which contributes to cold response in wheat. Overexpression of TaSAMT1-B improves freezing tolerance, while knockout reduces it. TaSAMT1-B affects MeSA and SA accumulation under freezing stress, with higher MeSA levels in overexpression lines and lower in knockout lines. Exogenous MeSA application rescues freezing tolerance in TaSAMT1 mutants, but SA does not. TaBZR1 directly binds to the TaSAMT1 promoter, regulating its transcription. TaBZR1 interacts with TaHAG1, which enhances TaSAMT1 expression through histone acetylation. TaBZR1 and TaHAG1 cooperatively activate TaSAMT1 transcription, increasing histone acetylation and enhancing freezing tolerance. These findings highlight the role of TaSAMT1 and its regulatory factors in wheat freezing tolerance, providing insights for improving cold tolerance in crops.