## 3 Results
### Carotenoid Content and Composition in Mango Pulp during Fruit Development and Ripening  
In mango pulp, six carotenoids were also detected. The major carotenoid accumulated in pulp was \(\beta\)-carotene, which accounted for 70% of total carotenoids. The minor carotenoids were all-trans-violaxanthin, 9-cis-violaxanthin, lutein, \(\beta\)-cryptoxanthin, and \(\alpha\)-carotene, which accumulated at low levels during fruit development and ripening. The changing patterns of carotenoids accumulated in the pulp were similar to the peel, but a smaller amount of carotenoids was found in the pulp. The total carotenoid content was continuously increased toward fruit development and achieved the maximum at the full ripening stage (98 days after full bloom). Among three cultivars, 'Kaituk' had the highest total carotenoid content in the pulp in all stages. At the full ripening stage, the total carotenoid content in 'Kaituk' was 1.6 and 2.5 times higher than 'Nam Dok Mai No.4' and 'Nam Dok Mai Sithong', respectively (Figure 6). The Expression of Genes Involved in Carotenoid Metabolism Pathway in Mango Peel during Fruit Development and Ripening  
To gain an understanding of the regulatory mechanism of carotenoid metabolism in mango, the expression of eight carotenoid biosynthesis genes (MiPSY, MiPDS, MiZDS, MiCRTISO, MiLCYb, MiLCYe, MiHYb, and MiZEP) and three carotenoid catabolic genes (MiCCD1, MiNCED2, and MiNCED3) was analyzed in the peel of three mango cultivars during fruit development and ripening. For carotenoid biosynthetic genes, as shown in Figure 7, the expression of MiPSY, MiZDS, MiLCYb, and MiZEP progressively increased during fruit development in the three mango cultivars. 'Kaituk' exhibited a higher expression level of those genes during fruit development and ripening compared to that of two cultivars. Contrastingly, the changes in the expression of MiPDS, MiCRTISO, MiLCYe, and MiHYb fluctuated in the three cultivars (Figure 7). Figure 6: Changes in carotenoid content and compositions in pulp of mango fruit cv. ‘Nam Dok Mai Sithong’, ‘Nam Dok Mai No. 4’ and ‘Kaituk’ during fruit development (45-88 days) and full ripening stage (98 days). The vertical bars represent the means with SE for three replications. For carotenoid catabolic genes, it was found that the expression of MiCCD1 continuously declined in 'Kaituk' over fruit development and ripening. In the meantime, the expression of MiCCD1 increased in the early development stage and then decreased in the ripening stage in 'Nam Dok Mai No.4'. Contrastingly, the expression of MiCCD1 fluctuated and rapidly increased in 'Nam Dok Mai Sithong'. The expression of MiNCED2 was unsteady before it dramatically dropped to a low level in 'Kaituk', while it gradually increased in 'Nam Dok Mai No.4' and 'Nam Dok Mai Sithong'. The expression of MiNCED3 was unsteady before it markedly decreased in 'Kaituk' and continuously decreased over fruit development and ripening in 'Nam Dok Mai No.4'. In contrast, the expression of MiNCED3 continuously increased during fruit development and ripening in 'Nam Dok Mai Sithong' (Figure 7). The Expression of Genes Involved in Carotenoid Metabolism Pathway in Mango Pulp during Fruit Development and Ripening  
The expression of carotenoid metabolic genes was performed in the pulp of three mango cultivars. For carotenoid biosynthetic genes, as shown in Figure 8, the expression of MiZDS and MiLCYb considerably increased during fruit development and ripening. The expression of those two genes was higher in 'Kaituk' than in the other two cultivars in all developmental stages. Contrastingly, the expression of other carotenoid biosynthetic genes exhibited a fluctuating trend among different fruit developmental stages and mango cultivars (Figure 8). Figure 7: The expression of genes involved in carotenoid metabolism in peel of mango fruit cv. ‘Nam Dok Mai Sithong’, ‘Nam Dok Mai No. 4’ and ‘Kaituk’ during fruit development (45–88 days) and full ripening stage (98 days). The vertical bars represent the means with SE for three replications.