Carotenoid accumulation and expression of carotenoid biosynthesis genes in mango flesh during fruit development and ripening

In order to investigate the regulation mechanisms of carotenoid biosynthesis in mango flesh, carotenoid content and the expression patterns of 15 carotenogenic gene in flesh of two mango cultivars 'Tainong1'and 'Hongyu' were analsyed during fruit development and ripening. Carotenoid were increasingly accumulated during fruit growth and sharply incaresed during postharvest ripening in both cultivars. In ripe fruit, total carotenoid content in the flesh of 'Tainong1' was 177.16 ug/g (Fresh weight) FW, and for 'Hongyu' 36.24 ug/gFW. The major carotenoids in the flesh were β-Carotene and α-carotene,with minor carotenoids being β-cryptoxanthin, zeaxanthin, lutin and neoxanthin. RT-PCR analysis revealed that the expression of carotenogenic genes CRTISO, PSY, ZDS, BCH and ZEP were up-regulated in flesh, whereas the transcript levels of LCYB, LCYE and NCED were down-regulated in two cultivars and during fruit development and ripening. CRTISO, PSY, ZDS, BCH and ZEP transcripts were significantly positively correlated with the total carotenoids content, while no differences were detected for CRTISO expression between cultivars. These results suggested that PSY, ZDS, BCH and ZEP coordinately contribute to carotenoid accumulation during mango fruit development and ripening.