Abstract: Narcissus tazetta var. chinensis‘Jinzhan Yintai’and N. pseudonarcissus L.‘Pink Charm’
were used as experimental materials in this study. The comparison of carotenoid biosynthetic gene
expression between the yellow corona of‘Jinzhan Yintai’and the red corona of‘Pink Charm’was
performed by real-time PCR. The ultrastructures of chromoplasts in red corona，yellow corona and white
petal were investigated by transmission electron microscopy. In addition，the full length cDNA of
chromoplast-specific carotenoid-associated synthase（CHRC）was cloned from‘Jinzhan Yintai’by RACE
method and the expression of CHRC was also analyzed. The results showed that the accumulation of
abundant β-carotenoid and the formation of red corona in‘Pink Charm’were due to the difference in the
expression of carotenoid biosynthetic genes between red and yellow corona，especially due to the
decreasing of LYCE expression. Chromoplasts in yellow or red coronas were the same style with many
homocentric membranes. The structure and amount of chromoplasts were not related to the red pigmentation formation. However，there were more numbers of plastoglobules observed in chromoplasts of red corona，
demonstrating that the red corona had the stronger capacity of pigment accumulation，which may be
caused by the increasing expression of CHRC. The results also showed that the structure of chromoplasts
in white petal of‘Jinzhan Yintai’was quite different from its corona’s，and plastoglobules were scarce and
smaller in size. These results provide new insight into the mechanism of colour formation in Nacissus and
the basis for the gene engineering of flower colour in Chinese narcissus.

Key words: Narcissus, red corona, carotenoid, gene expression, chromoplast, CHRC