Abstract
BACKGROUND/OBJECTIVES: Abiotic stresses severely constrain the yield of Brassica juncea, and aldehyde dehydrogenases (ALDHs) play a pivotal role in plant stress resistance. This study aims to systematically identify the ALDH gene family members in B. juncea and elucidate their expression patterns under salt and drought stress. METHODS: Using the Arabidopsis thaliana AtALDH proteins as seed sequences, BLASTp alignment was performed against the B. juncea whole-protein sequence database, combined with the conserved domain PF00171 of the ALDH proteins. A total of 39 BjALDH gene family members were identified, and their physicochemical properties, structures, phylogenetic relationships, interspecies collinearity, and intraspecies collinearity were analyzed. The qRT-PCR method was employed to quantify the relative expression levels of the BjALDH genes potentially associated with stress resistance under various treatments, and their effects on drought and salt stress tolerance were evaluated. RESULTS: The results demonstrated that BjALDH were universally significantly upregulated under salt stress, while exhibiting predominantly upregulated trends under drought stress. These findings suggest that BjALDH may enhance plant resistance to both salt and drought stress by modulating the aldehyde metabolic pathways. CONCLUSIONS: This study provides a theoretical basis for elucidating the functional roles and molecular genetic mechanisms of the BjALDH gene family in B. juncea under salt and drought stress.