Abstract: Carotenoid isomerase (CRTISO) is a key enzyme in the pathway of carotenoid, which can catalyze the structure of carotenoids from cis-to trans-. Full length of crtiso in Dunadiella viridis was acquired by RNA-sequencing, then, the sequence was analyzed by several bioinformatics softwares. Transcriptional levels of D. viridis treated by different concentration of acetylsalicylic acid (ASA) and arachidonic acid (AA) were checked by real-time quantitative PCR. The full cDNA length of crtiso was 1176 bp. It contained a 795 bp open reading frame (ORF), encoding 264 amino acids. Relative molecular mass was 29 522.6. Theoretical isoelectric point of the protein was 5.86. It was predicted that the CRTISO in D. viridis was properly targeted to the cytoplasmic matrix. Compared with amino acid sequences in NCBI database, it was found that the amino acid sequence of CRTISO shared the highest homology with Chlorella variabilis (78%). RT-qPCR showed that the transcription level of crtiso reached the maximum when the concentration of AA got 62.5 mg/L and ASA reached 50 mg/L. The result of carotenoid content showed that the carotenoid content reached the maximum when the concentration of AA got 312.5 mg/L and ASA reached 100 mg/L. There was certain correlation between the expression of crtiso gene and the content of carotenoids.

Key words: Dunaliella viridis, carotenoid isomerase , bioinformatic, carotenoid