Fig. 8: H and G-type monomers are funneled to the protocatechuate ortho-cleavage pathway.

a Representative scheme of 4HBA and vanillate conversion into protocatechuate (PCA) in X. citri 306. b Volcano plot of RNA-seq data highlighting the XAC0356 (pobA) gene upregulated in the 4HBA condition. Differential gene expression was calculated by edgeR⁷⁶ according to likelihood ratio test within a negative binomial generalized log-linear model framework. Genes with |log₂FC | >1 and adjusted p-value < 0.05 were assigned as DEGs. c Growth curve of pobA knockout strain on XVM2m supplemented with only glucose (G, light gray), only 4HBA (light green), or with HBA and glucose (4HBA(G), dark green). d 4HBA (green, left y axis) and glucose (gray, right y axis) consumption during the growth of WT (dashed lines) and ΔpobA strains (continuous lines) in the XVM2m medium supplemented with 4HBA and glucose. e Volcano plot of RNA-seq data highlighting the XAC0362-63 genes upregulated in the vanillin condition. Statistics were calculated as described in panel b. f HPLC analysis showing vanillate accumulation only by the ΔXAC0362-63 (KO362-63) strain. g Schematic representation of the genomic context of pca genes, the corresponding metabolic steps, and a heat map of RNA-seq data (log₂ Fold Change) showing the pca genes up-regulated under conditions containing H and G-type aromatic compounds as well as benzaldehyde. log₂ Fold Change was calculated using edgeR⁷⁶ based on likelihood ratio test within a negative binomial generalized log-linear model framework. COALC coniferyl alcohol, VAN vanillin, 4HBA 4-hydroxybenzoate, 4HBZ 4-hydroxybenzaldehyde, BZD benzaldehyde (BZD), SYALD syringaldehyde, PCA protocatechuate, β-CM β-carboxy-cis,cis-muconate, 2-CDA γ-carboxymuconolactone, β-KA EL β-ketoadipate enol-lactone, β-KA β-ketoadipate, β-KA-CoA β-ketoadipyl-CoA. Genes were considered up-regulated according to the criteria, log₂ Fold Change ≥ 1, with adjusted p-value ≤ 0.05. (*) indicate genes with log₂ Fold Change ≥ 1 that do not fit the adjusted p-value ≤ 0.05 criterion. In c, d and f panels symbols and error bars represent mean ± SD of n = 3 biological replicates. Source data are provided as a source data file.