Analysis of Fruit Quality Traits in Mango Towards Marker Assisted Breeding

Mango is one of the most important fruit crops in tropical and subtropical regions. Flesh color is a key element in mango marketing in the Western world. In order to understand color development in mango we identified 88 gene candidates involved in color formation pathways, of anthocyanin and carotenoid synthesis as well as in chlorophyll degradation, from assembled ‘Keitt’ transcriptome. We followed their expression patterns during fruit development and ripening. Expression of specific genes involved in chlorophyll degradation and carotenoid synthesis correlated with the levels of the pigments. However, unlike in other fruits, the expression of anthocyanin biosynthetic genes did not correlate with the accumulation of anthocyanins. Specifically, UFGT, ANS as well as other genes were highly expressed at ripening even in non-colored cultivars. We identified 5 different transcription factors that correlated with expression patterns of anthocyanin biosynthesis structural genes (but not with anthocyanin accumulation). Biochemical analysis suggests that anthocyanins are polymerized into non-colorful condensed pro-anthocyanins.

Variation in sequence of color formation genes was identified using variation between the transcriptomes of two mango cultivars ‘Keitt’ and ‘Tommy-Atkins’ differing in their color pattern. Several SNPs were highly correlated with color and will be tested in segregating populations.