Cloning and Expression Analysis of CaBGLU21 Gene in Pepper (Capsicum annuum)
YANG Yuan-Cai, LIANG Yan-Ping, JIAO Yan-Sheng, MIAO Ru-Yi, TIAN Ru-Xia*
College of Horticulture/Shanxi Key Laboratory of Germplasm Resources Innovation and Utilization of Vegetable and Flower, Shanxi Agricultural University, Taiyuan 030000, China
Abstract：β-glucosidase (BGLU) is a key enzyme involved in plant hormone regulation and stress response, and functional characterization of BGLU family genes is of great importance for genetic improvement of stress resistance in pepper (Capsicum annuum). Using the inbred line '17CL30' of pepper as the experimental material, this study cloned the pepper β-glucosidase 21 gene (C. annuum β-glucosidase 21, CaBGLU21)(GenBank No. PX753275.1), and performed systematic analysis on its bioinformatics characteristics, expression pattern and cis-acting elements in the promoter region. The results showed that CaBGLU21 encoded a stable alkaline hydrophilic protein containing 406 amino acids, which harbored a conserved Glyco_hydro_1 domain and multiple potential phosphorylation sites. Phylogenetic analysis indicated that CaBGLU21 had the closest genetic relationship with BGLU proteins from Solanaceae species, including Solanum lycopersicum, Nicotiana tabacum and Lycium ferocissimum. Promoter analysis revealed that the promoter sequence of CaBGLU21 contained cis-acting elements associated with light response, hormone response (MeJA, ABA, SA) and adversity stress. qRT-PCR results demonstrated that the expression of CaBGLU21 was significantly induced by various treatments including ABA, JA, IAA, GA3, H2O2, NaCl, high temperature and low temperature, with its expression level reaching the peak at around 12 h after treatment. The results of this study preliminarily showed that CaBGLU21 might play an important role in pepper's response to hormone signals and abiotic stresses. This study provides a reference for in-depth dissection of the gene's function and provided candidate gene resources for pepper breeding for stress tolerance.
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