Figure 6.

The Peroxisomal Transporter PXA1 Is Involved in Ubiquinone Biosynthesis from Phenylalanine.

(A) Total ubiquinone (reduced and oxidized) levels in the leaves of wild-type and pxa1 knockout Arabidopsis plants. Data are means of four biological replicates ± se. Asterisk annotations indicate significant difference from the wild type as determined by Fisher’s test (P < α = 0.05) from ANOVA. FW, fresh weight.

(B) Total ubiquinone-[Ring-¹³C₆] levels in axenically grown wild-type and pxa1 knockout Arabidopsis plants fed with 100 μM doses of Phe-[¹³C₉] or Tyr-[¹³C₉;¹⁵N] for 3 h. Data are means of four biological replicates ± se. Asterisk annotations indicate significant difference from the wild type as determined by Fisher’s test (P < α = 0.05) from ANOVA.

(C) Total ubiquinone levels in axenically grown wild-type and pxa1 knockout Arabidopsis plants fed for 24 h with 200 μM t-cinnamate, p-coumarate, or 4-hydroxybenzoate (4-HB). Data are means of three to five biological replicates ± se. Asterisk annotations indicate significant difference from the corresponding DMSO control as determined by Fisher’s test (P < α = 0.05) from ANOVA.

(D) Phylloquinone levels in the leaves of wild-type pxa1 Arabidopsis plants. Data are means of three biological replicates ± se. Wild-type and pxa1 values are not significantly different as determined by Fisher's test from ANOVA (P > 0.4).