Abstract: Based on the sequence information of Unigene of Osmanthus fragrans ‘Yanhong Gui’ from the petal transcriptome database,sequence of open reading frame in one carotenoid isomerase gene（OfCRTISO）from Osmanthus fragrans was amplified using RT-PCR technology and confirmed by sequencing. Bioinformatics analysis indicated that OfCRTISO contained a 1 842 bp open reading frame,encoding 613 amino acid residues. OfCRTISO from Osmanthus fragrans shared high sequence similarity with CRTISOs from Pedaliaceae and Solanaceae plants. Phylogenetic analysis showed that OfCRTISO and Sesamum indicum CRTISO（XP_011077785）gathered into one branch,revealing that these two proteins showed the closest genetic relationship. Gene expression analysis implicated that the expression level of OfCRTISO was extremely low at bud former stage,gradually increased at bud later stage,and reached the peak at initial flowering stage;however,it significantly decreased at full flowering stage. According to the expression analysis of OfCRTISO in the petals of sweet osmanthus cultivars with different flower color,it was demonstrated that the expression level of OfCRTISO at initial flowering stage might have an impact on the carotenoid accumulation in the petals of sweet osmanthus cultivars at full flowering stage.

Key words: Osmanthus fragransl, petal color, carotenoids, carotenoid isomerase gene