T fraction in the mobilized Fe was trapped by BPDS and this fraction also increased linearly when the concentration of fraxetin improved from to (Figure B).DISCUSSIONArabidopsis thaliana plants produce and secrete an array of phenolics in response to Fe deficiency when the pH with the nutrient remedy is high.Phenolics found within this study contain a number of coumarinolignans not previously reported inside a.thaliana (cleomiscosins A, B, C, and D along with the hydroxycleomiscosins A andor B), also as other previously reported coumarins (scopoletin, fraxetin, isofraxidin and fraxinol) and some coumarin precursors (ferulic acid and GNF351 MedChemExpress coniferyl and sinapyl aldehydes).The identification of all these phenolic compounds was achieved by way of an integrative interpretation of analytical data, like exact molecular masstocharge ratios (mz), low and highresolution MSn spectra, PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/21543622 chromatographic RTs and fluorescenceUVVIS data.Additionally, we report here for the first time on the quantification of all identified coumarins, revealing that Fe deficiency primarily induced the root accumulation and exudation in the noncatechol coumarin scopoletin and also the catechol coumarin fraxetin, with the exudation of fraxetin becoming far more prominent when Fe chlorosis was intense.Also, we show for the initial time that fraxetin, but not scopoletin, was successful to mobilize Fe from an scarcely soluble Fe(III)oxide.FIGURE Iron mobilization from an scarcely soluble Fe(III)oxide as impacted by coumarins.(A) Structureactivity connection of coumarins on Fe mobilization activity.The assays consisted inside the incubation of mg of Fe(III)oxide with a solution of (blank) or in the indicated coumarins and BPDS at two distinctive pH values, .and .Total Fe and Fe(II)(BPDS) in option were determined by ICPMS and spectrophotometry, respectively.(B) Effects from the fraxetin concentration on the Fe mobilization activity at pH .Scatter plot with the concentration of fraxetin vs.the total Fe mobilized and the Fe(II), with linear regression lines in black and their corresponding equations.In all instances (A,B), information are means SE (n ) and asterisks denote a statistically significant distinction among blank plus a coumarincontaining assay medium as determined by Student’s t test (p ).Frontiers in Plant Science www.frontiersin.orgNovember Volume ArticleSisTerraza et al.Coumarins in FeDeficient Arabidopsis PlantsThis would be the very first time cleomiscosins and hydroxycleomiscosins have already been reported inside a.thaliana.Cleomiscosins were discovered in each roots and nutrient solutions, whereas hydroxycleomiscosins were identified only in nutrient options (Figures B and B).All coumarinolignans identified possess a fraxetin moiety linked to distinctive phenylpropanoid units (Figure C).Nonconventional lignans, such as coumarinolignans and other hybrid ones, harbor a single phenylpropanoid unit, whereas traditional ones consist in phenylpropanoid dimers.The frequent coumarin moiety within the coumarinolignans located, fraxetin, has been consistently reported to boost with Fe deficiency in roots and development media of A.thaliana (Figures and ; Fourcroy et al Schmid et al Schmidt et al).The phenylpropanoid units found would be the principal lignin precursors coniferyl (in cleomiscosins A and B) and sinapyl alcohols (in cleomiscosins C and D), as well as the noncanonical monolignol hydroxyconiferyl alcohol (in hydroxycleomiscosins A and B) (Begum et al) (Figure C).Previously, two other coumarinolignans, composed of esculetin and either coniferyl alc.
