Fig 1.
(A) Simplified illustration of the flavonoid biosynthesis with focus on the flavone biosynthesis. CHS (naringenin-chalcone synthase), CHI (chalcone isomerase), F3H (flavanone 3-hydroxylase), F3’H (flavonoid 3’-hydroxylase), and FNS (flavone synthase). (B) Reactions catalyzed by FNS I and F3H in the context of the flavonoid biosynthesis.
Fig 2.
(A) Maximum likelihood tree of F3H and FNS I sequences. Apiaceae FNS I sequences form a nested cluster within the F3H context. The FNS I sequences of non-Apiaceae species are placed outside the F3H clade. Polypeptide sequences used for the construction of this tree are included in S1 File. A full phylogenetic tree with sequence names is included as S3 File. (B) Apiaceae clade in the maximum likelihood tree of F3H and FNS I sequences. Sequences analyzed in Table 1 are written in bold. Classification of sequences in the Apiaceae F3H, Apiaceae FNS I, and Apiaceae FNS I-clades were supported by RAxML, FastTree, MEGA, and IQ-TREE analyses. Support values above 50 are given for the individual branches.
Table 1.
Inspection of diagnostic amino acid residues in FNS I and F3H candidates of Daucus carota and Apium graveolens.
Fig 3.
Syntenic region between the Apiaceae species Daucus carota and Apium graveolens shows F3H (skyblue) and FNS I (orange) in close proximity, while FNS I was not observed in the basal Apiaceae species Centella asiatica or in the outgroup Panax ginseng.
Fig 4.
Expression of F3H, FNS I, and FNS I-like genes in carrots.
(A) This plot shows the distribution of transcript per million (TPM) values across 146 RNA-seq data sets derived from different tissues/organs and conditions (S2 File). These aggregated expression data reveal that F3H (DCAR_009483) and FNS I (DCAR_009489) are expressed in several samples, while FNS I-like (DCAR_009487) is only weekly expressed in a few selected samples and FNS I-like (DCAR_009488) is almost not expressed at all. (B-F) Plots show the expression of the four genes in specific tissues covering flower, leaf, phloem, petiole, and root. This tissue-specific gene expression analysis was restricted to samples with available metadata about the respective sample.