Comprehensive Quantification of (Poly)phenols in <i>Lotus japonicus</i> with and without Arbuscular Mycorrhizal Symbiosis

In the present study, a highly specific, accurate, and robust ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous quantification of 50 plant (poly)phenol analytes was developed and validated to assess the effect of arbuscular mycorrhizal (AM) symbiosis on the (poly)phenolic content of the model legume <i>Lotus japonicus</i> (<i>L. japonicus</i>). Determination of molar concentrations of analytes in roots and shoots of wild-type and AM mutant <i>L. japonicus</i> (with and without AM symbiosis, respectively) revealed an overall increase in (poly)phenols in mycorrhizal plants. Time-course observation over 10 weeks showed a shift in (poly)phenol concentrations, especially in the roots. In total, 13 analytes were notably more abundant in young AM roots, suggesting a potential role in symbiosis initiation. An accumulation of various (poly)phenols at later stages of symbiosis might indicate a potential involvement in arbuscule degradation or AM autoregulation.