Effective expression of taste-modifying protein miraculin fusing FMDV 2A gene in Chlamydomonas reinhardtii

Miraculin is a taste modification protein derived from plants, which can change sour taste into sweet taste, and has great application potential in food industry. Currently, the extraction of miraculin presented some problems such as cumbersome process and low purity. Chlamydomonas reinhardtii is a potential expression system of exogenous proteins. However, the exogenous genes are integrated randomly in genome of C. reinhardtii during transformation, which leads to significant expression variability among transformants. The 2A peptide from FMDV virus has been proven to effectively improve the expression efficiency of exogenous proteins in multi-gene expression systems through self-cleavage mechanism. In presented study, the expression vector pSP108–2A-miraculin containing 2A-miraculin fusion gene was constructed and transformed into C. reinhardtii by glass bead method. Two positive strains were obtained through bleomycin resistance selecting. The detection results showed that miraculin gene was integrated into the genome of C. reinhardtii cells at the molecular level, and was successfully expressed at the protein level. This study was the first time to express the miraculin in C. reinhardtii, which provided an optional way to obtain miraculin.