Transcriptomics and Metabolomics Reveal the Critical Genes of Carotenoid Biosynthesis and Color Formation of Goji (Lycium barbarum L.) Fruit Ripening

Abstract

Carotenoids in goji (<i>Lycium barbarum</i> L.) have excellent health benefits, but the underlying mechanism of carotenoid synthesis and color formation in goji fruit ripening is still unclear. The present study uses transcriptomics and metabolomics to investigate carotenoid biosynthesis and color formation differences in N1 (red fruit) and N1Y (yellow fruit) at three stages of ripening. Twenty-seven carotenoids were identified in N1 and N1Y fruits during the M1, M2, and M3 periods, with the M2 and M3 periods being critical for the difference in carotenoid and color between N1 and N1Y fruit. Weighted gene co-expression network analysis (WGCNA), gene trend analysis, and correlation analysis suggest that <i>PSY1</i> and <i>ZDS16</i> may be important players in the synthesis of carotenoids during goji fruit ripening. Meanwhile, 63 transcription factors (TFs) were identified related to goji fruit carotenoid biosynthesis. Among them, four TFs (<i>CMB1-1</i>, <i>WRKY22-1</i>, <i>WRKY22-3</i>, and <i>RAP2-13-like</i>) may have potential regulatory relationships with <i>PSY1</i> and <i>ZDS16</i>. This work sheds light on the molecular network of carotenoid synthesis and explains the differences in carotenoid accumulation in different colored goji fruits.