Transcriptome analysis reveals association of carotenoid metabolism pathway with fruit color in melon

Flesh color is an important quality of melon (Cucumis melo L.) and is determined mainly by carotenoid content, awarding them with colors, aromas, and nutrients. enhancing the nutritional and health benefits of fruits and vegetables for humans. In this study, we performed transcriptomic analysis of two melon inbred line B-14 (orange-flesh) and B-6 (white-flesh) at three developmental stages. We observed that the beta-carotene content of inbred line B-6 (14.232 mu g/g) was significantly lower than that of inbred line B-14 (0.534 mu g/g). RNA-sequencing and quantitative reverse transcription PCR analyses were performed to identify differentially expressed genes (DEGs) between the two inbred lines at different stages; the DEGs were analyzed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes databases (KEGG). We identified 33 structural DEGs in different developmental periods of the two lines that were related to carotenoid metabolism. Among them, PSY, Z-ISO, ZDS, CRTISO, CCD4, VDE1, and NCED2 were highly correlated with carotenoid content. Thus, this study provides a basis for molecular mechanism of carotenoid biosynthesis and flesh color in melon fruit.

Automated summary

This study analyzed the transcriptome of two different-colored melon varieties and identified 33 genes related to carotenoid metabolism that are important for flesh color formation.