Figure 2.

PAP, and Not IPs, Accumulates in alx8.

(A) to (C) Analyses of phosphoinositols in different genotypes. Five to six 10-d-old Col-0 (A), alx8 (B), or fry1-6 (C) seedlings were labeled with myo-[2-³H]inositol for 72 h and IPs extracted in HCl prior to separation by HPLC. Chromatograms show representative profile of phosphoinositols of one of two independent experiments. The intensity and periodicity of the peaks corresponding to inositol mono-, bis-, and hexakisphosphate (arrows) are similar in all genotypes.

(D) Isolation and identification of phosphoadenosine nucleotides. Metabolites were extracted from leaves of 30-d-old plants and adenosines fluorescently labeled by derivatization. PAPS, APS, and PAP in wild-type Col-0 (black) and alx8 (gray) were identified by coelution with external PAP standard (dashed black line). A typical chromatogram is shown. Note that approximately fourfold less extract of alx8 than Col-0 was injected in this experiment. Quantification was undertaken using a standard curve (see Supplemental Figure 4 online).