Objective Capsicum chinense is one of the main cultivated species of pepper, which generally has a strong fruit aroma formed by branched chain esters. AAT (alcohol acyl-CoA transferase) catalyzes the last step in the synthesis of branched chain esters and has an important impact on its content. Identification of the AAT gene family in C. chinense and analysis on its expression patterns will provide references for its functional studies.

Method Bioinformatics and real-time quantitative PCR analysis were applied to identify the AAT gene family of C. chinense and analyze its expression patterns.

Result Ten members of the AAT gene family were identified and named CcAAT1-CcAAT10 according to their distribution order on six chromosomes. Physicochemical properties prediction revealed that the length of amino acid sequence encoded by AAT gene family range from 256 to 683 aa, with their molecular mass ranging from 29 to 77 kDa, and isoelectric point ranging from 5.34 to 8.79. Average hydrophobic coefficients of them were all negative values. Their instability indexes ranged 23.76 to 51.02. Protein structure prediction showed that their secondary structure was dominated by α-helices and irregular convolutions, and the tertiary structure varied widely. Subcellular localization prediction revealed that all CcAAT were located in the cytoplasm and 16 cis-regulatory elements were found on their gene promoter. Spatiotemporal expression analysis showed that CcAAT5 and CcAAT6 had no detectable expression, CcAAT8 was specifically expressed in flowers and fruits, CcAAT1, CcAAT3 and CcAAT7 were highly expressed in leaves, and CcAAT4 was highly expressed in roots.

Conclusion It clarified the expression pattern of the AAT gene family in C. chinense and it was hypothesized that CcAAT8 might be a key gene affecting the content of branched chain esters.