Abstract:

The effects of bagging and debagging treatments on fruit coloration and anthocyanin
biosynthesis were explored，and the molecular mechanism of light regulating anthocyanin biosynthesis was
discussed. In this study，litchi‘Guiwei’was used as material to investigate the effects of light on fruit
coloration and expressions of structural genes and MYB transcription factor in anthocyanin biosynthetic
pathway by shading fruit panicles with double-layer kraft paper bag and debagging at one week before harvest. Anthocyanin biosynthesis was suppressed completely，and all the tested structural genes and MYB
transcription factor were down-regulated in the pericarp of bagged fruits. After bag removal，the content of
anthocyanin in pericarp increased rapidly within a week. All genes tested were up-regulated after exposure
to light during fruit maturation and coloration，but the peaks of their expressions occurred at different
period. Among the genes tested，the expressions of LcDFR，LcF3'H，LcUFGT，and LcMYB1 were
paralleled with the pericarp anthocyanin accumulation. These results suggested that illumination was essential
for expression of the anthocyanin biosynthetic genes and therefore pigmentation. LcDFR，LcF3'H，
LcUFGT and LcMYB1 might play important roles in process of light regulating anthocyanin biosynthesis.

Key words: litchi, light, fruit coloration, anthocyanin, structural gene, MYB transcription factor