Integrated Transcriptomic\nand Metabolomic Analysis\nRevealed Regulatory Mechanisms on Flavonoids Biosynthesis in the Skin\nof Passion Fruit (<i>Passiflora</i> spp.)

Passion fruit is one of the most famous fruit crops in\ntropical\nand subtropical regions due to its high edible, medicinal, and ornamental\nvalue. Flavonoids, a class of plant secondary metabolites, have important\nhealth-related roles. In this study, a total of 151 flavonoid metabolites\nwere identified, of which 25 key metabolites may be the main contributors\nto the purple phenotype. Using RNA sequencing, 11,180 differentially\nexpressed genes (DEGs) were identified. Among these, 48 flavonoid\nbiosynthesis genes (<i>PAL</i>, <i>4CL</i>, <i>C4H</i>, <i>CHS</i>, <i>CHI</i>, <i>F3H</i>, <i>DFR</i>, <i>ANS</i>, and <i>UFGT</i>) and 123 transcription factors were identified. Furthermore,\n12 distinct modules were identified through weighted gene coexpression\nnetwork analysis, of which the brown module displays a robust positive\ncorrelation with numerous flavonoid metabolites. Overexpression of <i>PeMYB114</i> significantly promoted flavonoids accumulation\nin tobacco leaves. Our study provided a key candidate gene for molecular\nbreeding to improve color traits in passion fruit.