Characterization and Expression Analysis of β-Glucosidase Gene Under Abiotic Stresses in Pepper ( L.).

: Pepper ( L.) is highly susceptible to various abiotic stresses during their growth and development, leading to severe reductions in both yield and quality. β-Glucosidase (BGLU) is widely involved in plant growth and development, as well as in the response to abiotic stress. : We performed a genome-wide identification of pepper () genes. Phylogenetic analysis included BGLU proteins from , tomato, and pepper. Gene structures, conserved motifs, and promoter cis-elements were analyzed bioinformatically. Synteny within the pepper genome was assessed. Protein-protein interaction potential was predicted. Gene expression patterns were analyzed across tissues and under abiotic stresses using transcriptomic data and qRT-PCR. Subcellular localization of a key candidate protein CaBGLU21 was confirmed experimentally. : We identified 32 genes unevenly distributed across eight chromosomes. Phylogenetic classification of 99 BGLU proteins into 12 subfamilies revealed an uneven distribution of CaBGLUs across six subfamilies. Proteins within subfamilies shared conserved motifs and gene structures. promoters harbored abundant light-, hormone- (MeJA, ABA, SA, GA), and stress-responsive elements (including low temperature). A duplicated gene pair (/) was identified. 27 CaBGLU proteins showed potential for interactions. Expression analysis indicated and were mesophyll-specific, while was constitutively high in non-leaf tissues. was consistently upregulated by cold, heat, and ABA. Subcellular localization confirmed CaBGLU21 resides in the tonoplast. : This comprehensive analysis characterizes the pepper gene family. , exhibiting constitutive expression in non-leaf tissues, strong upregulation under multiple stresses, and tonoplast localization, emerges as a prime candidate gene for further investigation into abiotic stress tolerance mechanisms in pepper. The findings provide a foundation for future functional studies and stress-resistant pepper breeding.