Abstract:

The yellow-fleshed loquat‘Zaozhong 6’and the white-fleshed loquat‘Baiyu’were used
as materials，the accumulation of carotenoids in peel and pulp during different fruit development stages
were detected，and the expression of 15 carotenogenic genes were analysized. During loquat fruit
ripening，the content of β-carotene in peel and pulp of‘Zaozhong 6’increased gradually and peaked at the
fully ripe stage，in the peel it was 68.53 μg ? g-1 FW，while in the pulp it was 11.92 μg ? g-1 FW. And in the
peel of‘Baiyu’，the content of β-carotene increased and peaked at the fully ripe stage，reached to 38.89
μg ? g-1 FW，while it decreased in the pulp of‘Baiyu’，from the original 0.47 μg ? g-1 FW reduced to 0.29
μg ? g-1 FW；The content of β-cryptoxanthin in the peel and pulp of‘Zaozhong 6’and‘Baiyu’bothincreased steadily，and peaked at the fully ripe stage；However，the content of lutein decreased in the peel
of ‘Zaozhong 6’and increased in the pulp of ‘Zaozhong 6’；It droped and then rised in the peel of ‘Baiyu’，
and there was no significant change of β-cryptoxanthin in the pulp of‘Baiyu’. After the breaker stage，the
mRNA levels of phytoene synthase（PSY）and chromoplast-specific lycopene β-cyclase（CYCB）were
higher in the peel，and CYCB and β-carotene hydroxylase（BCH）mRNAs were higher in the flesh of
‘Zaozhong 6’，compared with‘Baiyu’. The results showed that the expression level of PSY，CYCB and
BCH was likely to cooperatively regulate the accumulation of carotenoids.

Key words: loquat, carotenoids, gene, expression