This study investigates the role of branched-chain amino acids (BCAAs) and vitamin B5 (VB5) in rice's response to salt stress. The researchers identified OsBCAT2, a gene responsible for BCAA degradation, which positively regulates salt tolerance by promoting VB5 synthesis. Salt stress induces the expression of OsBCAT2, leading to increased BCAA degradation and higher levels of VB5 intermediates. Overexpression of OsBCAT2 in rice plants enhances their salt tolerance, while mutants lacking OsBCAT2 exhibit reduced tolerance. The study also found that exogenous application of pantothenol, the biologically active form of VB5, rescues the salt stress-sensitive phenotype of OsBCAT2 mutants. These findings provide new insights into the molecular mechanisms by which BCAAs and VB5 contribute to rice's response to salt stress.This study investigates the role of branched-chain amino acids (BCAAs) and vitamin B5 (VB5) in rice's response to salt stress. The researchers identified OsBCAT2, a gene responsible for BCAA degradation, which positively regulates salt tolerance by promoting VB5 synthesis. Salt stress induces the expression of OsBCAT2, leading to increased BCAA degradation and higher levels of VB5 intermediates. Overexpression of OsBCAT2 in rice plants enhances their salt tolerance, while mutants lacking OsBCAT2 exhibit reduced tolerance. The study also found that exogenous application of pantothenol, the biologically active form of VB5, rescues the salt stress-sensitive phenotype of OsBCAT2 mutants. These findings provide new insights into the molecular mechanisms by which BCAAs and VB5 contribute to rice's response to salt stress.