Identification, Expression Analysis and Cloning of Capsicum chinense BCAT Gene Family

【Objective】The purpose of this study is to understand the distribution, properties and expression patterns of members of the BCAT (Branched-chain Aminotransferase) gene family, so as to lay a foundation for further research on the function of Capsicum chinense Jacq BCAT genes. C. chinense is one of the five main cultivars of pepper. Its fruit usually has a strong fruity aroma formed by branched chain esters. BCAT is responsible for catalyzing the synthesis of corresponding 2-oxo acids from branched-chain amino acids, and is the first reaction enzyme to catalyze the synthesis of branched-chain esters.【Method】The BCAT gene family members of C. chinense were identified, expressed and cloned using bioinformatics analysis and real-time quantitative PCR.【Result】Five members of the BCAT gene family were obtained and named as CcBCAT1~CcBCAT5, and then bioinformatics analysis and CcBCAT1-CcBCAT4 cloning were performed on them. Bioinformatics analysis showed that these genes were distributed on the four chromosomes of pepper, and the proteins were all hydrophilic proteins with amino acid lengths ranging from 184 aa to 557 aa, molecular weights ranging from 20.29 ku to 89.60 ku, and isoelectric points ranging from 5.57~8.34. Subcellular localization prediction results showed that CcBCAT1 was located in chloroplast and mitochondria, and other gene family members were located in chloroplast. The spatiotemporal expression analysis of CcBCATs genes showed that CcBCAT1-4 genes had tissue expression specificity. The regular expression of CcBCAT4 gradually increased with the maturity of pepper, and the accumulation trend of branched-chain amino acid derivatives related to pepper fruit was similar. CcBCAT5 was not detected.【Conclusion】In conclusion, this study clarified the expression pattern of the BCAT gene family in Chinese pepper, speculated that CcBCAT4 was involved in the synthesis of secondary metabolites related to pepper fruit.