Identification and Abiotic Stress Response of Adenosine 5'-phosphosulfate Reductase(APR)Gene Family in Brassica napus
The adenosine 5'-phosphosulfate reductase(APR)is a critical enzyme in the plant sulfate assimilation pathway,playing a vital role in sulfate metabolism and sulfur cycling.This protein comprises 2 conserved domains:PAPS_reductase and Thioredoxin,primarily exerting its catalytic function in the plastids,significantly impacting plant growth,development,and stress responses.To systematically investigate the structural and functional characteristics of the APR gene family in Brassica napus(oilseed rape),this study used 3 APR protein sequences from Arabidopsis thaliana as templates to perform homology analysis across the entire genome of B.napus.A total of 10 APR family genes were identified,distributed across 9 chromosomes.Further identification and analysis of the gene family were carried out and preliminary exploration of the expression response patterns of APR genes in B.napus under abiotic stress conditions was also initiated.The results revealed that the amino acid sequence lengths of B.napus APR proteins ranged from 219 to 468 residues,with molecular weights spanning from 24.29 to 51.69 kD,and isoelectric points varying between 5.43 and 8.84.Phylogenetic analysis classified the B.napus APR genes into 3 subclades,each containing members with similar exon-intron structures.All APR proteins were confirmed to possess the conserved PAPS_reductase and Thioredoxin domains.Collinearity analysis indicated that segmental duplication played a predominant role in the expansion of the B.napus APR gene family.Expression profiling showed that APR genes exhibited spatiotemporal expression specificity in various tissues at different developmental stages,with notably higher expression levels in cotyledons,rosette leaves,and silique pericarps.Analysis of cis-regulatory elements in promoters and expression patterns under abiotic stress conditions revealed that the promoter regions of B.napus APR genes were enriched with cis-elements associated with hormone response and stress adaptation.Furthermore,the expression of these genes was induced by heavy metal cadmium and lead stress,as well as sulfur deficiency stress.These findings suggest that APR genes in B.napus play significant roles in responding to cadmium and lead heavy metal stresses,providing reference for further investigation into the molecular functions of the APR gene family in B.napus.