LC-MS/MS analysis of thaxtomin A and its putative metabolite in wild type and Mprtn4ip1l mutant extracts.

Gemmalings from each line were grown on solid medium supplemented with 0.1% DMSO for 14 days, then transferred to solid ½ Gamborg medium supplemented with 5 μM thaxtomin A or 0.1% DMSO and grown for 2 days. Cellular fractions were extracted from thaxtomin A-treated and untreated samples. (A) A precursor ion analysis of samples from Tak-2 and Mprtn4ip1l^GE118 mutants was conducted via LC-MS/MS (n = 6). Chromatograms of the total ion currents of precursor ion scanning for m/z 247.1 are depicted. The peak eluting at a retention time of 8.99 min is Thaxtomin A (m/z 439.1), the peak eluting at a retention time of 9.25 min (m/z 394.1) is its putative metabolite. Both peaks are absent in the analysis of the untreated samples. (B) MS/MS of m/z 439.2 from thaxtomin A treated samples. The fragment ions m/z 219.1 and m/z 247.1 are identical to the fragment ions observed in the authentic standard of thaxtomin A and reported in the literature [83]. (C) MS/MS spectra of the unknown compound eluting at a RT of 9.25 min. Both prominent fragment ions of thaxtomin A are present. (D) A precursor ion analysis of samples from Tak-1 and Mprtn4ip1l^GE149 mutants was conducted via LC-MS/MS (n = 6). Chromatograms of the total ion currents of precursor ion scanning for m/z 247.1 are depicted. The peak eluting at a retention time of 8.99 min is Thaxtomin A (m/z 439.1), the peak eluting at a retention time of 9.25 min (m/z 394.1) is its putative metabolite.

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