Multi-omics analysis uncovers novel gene regulatory networks of flower coloration in Lagerstroemia indica

Abstract

Rich flower colors are valuable attributes for Lagerstroemia indica ornamental industry. To gain insights into the regulatory network controlling flower color formation and identify the key regulatory genes, in this study, we comprehensively analyzed the metabolome and transcriptome of three L. indica cultivars at the full bloom stage: red Dynamite, purple Lanmaizi, and white Yuzhuafendie. A total of 111 potential anthocyanin biosynthetic structural genes were screened and assigned among the 24 chromosomes. Significant up-accumulation of cyanidins in cv. Dynamite and petunidins in cv. Lanmaizi confer to them different flower colors. LiANS and LiOMT28, two structural genes, may work in tandem with transcription factors (TFs) from the MYB, bHLH, WDR, G2-like, ERF, WRKY, bZIP, and E2F/DP families to modulate color formation in L. indica petals, according to correlation tests of anthocyanin levels and transcriptional changes. Subsequent research confirmed the positive correlation between petal colorating processes and the transcripts of LiANS. Increased anthocyanin accumulation in leaves and petals, pale pink flower color, up-regulation of LiF3H1, LiF3H2, LiDFR, LiOMT29, and Lind24G0871 (R2R3 MYB), and down-regulation of Lind04G0622 (R2R3 MYB) were also observed in the LiANS-overexpressing shoots. These findings suggest that LiANS may assemble molecular modules with these structural genes and MYB TFs to participate in anthocyanin biosynthesis in L. indica. Further research on the intricate physiological processes and molecular mechanisms connected to the flower color and its regulatory networks in L. indica may benefit from the novel insights gained from the study.