In order to determine how plant uptake of a sulfur-rich secondary metabolite, sinalbin, affects the metabolic profile of sulfur-deficient plants, gas chromatography time-of-flight mass spectrometry (GC–TOF-MS), in combination with liquid chromatography–mass spectrometry (LC–MS), was used to survey the metabolome of Arabidopsis seedlings grown in nutrient media under different sulfur conditions. The growth media had either sufficient inorganic sulfur for normal plant growth or insufficient inorganic sulfur in the presence or absence of supplementation with organic sulfur in the form of sinalbin (p-hydroxybenzylglucosinolate). A total of 90 metabolites were identified by GC–TOF-MS and their levels were compared across the three treatments. Of the identified compounds, 21 showed similar responses in plants that were either sulfur deficient or sinalbin supplemented compared to sulfur-sufficient plants, while 12 metabolites differed in abundance only in sulfur-deficient plants. Twelve metabolites accumulated to higher levels in sinalbin-supplemented than in the sulfur-sufficient plants. Secondary metabolites such as flavonol conjugates, sinapinic acid esters and glucosinolates, were identified by LC–MS and their corresponding mass fragmentation patterns were determined. Under sinalbin-supplemented conditions, sinalbin was taken up by Arabidopsis and contributed to the endogenous formation of glucosinolates. Additionally, levels of flavonol glycosides and sinapinic acid esters increased while levels of flavonol diglycosides with glucose attached to the 3-position were reduced. The exogenously administered sinalbin resulted in inhibition of root and hypocotyl growth and markedly influenced metabolite profiles, compared to control and sulfur-deficient plants. These results indicate that, under sulfur deficient conditions, glucosinolates can be a sulfur source for plants. This investigation defines an opportunity to elucidate the mechanism of glucosinolate degradation in vivo.Graphical abstractGas chromatography time-of-flight mass spectrometry (GC–TOF-MS) in combination with liquid chromatography–mass spectrometry (LC–MS) was used to survey the metabolome of Arabidopsis seedlings in response to sulfur deficiency and sinalbin supplements.Highlights► Metabolite profiling of Arabidopsis seedlings in response to sulfur deficiency and sinalbin supplement. ► Identification and quantification of metabolites by GC–TOF-MS and LC–MS. ► Investigation of mass fragmentation patterns of flavonol conjugates, sinapinic acid esters and glucosinolates. ► Comparison of metabolite profiles by principal component analysis. ► Interpretation of metabolite differences via metabolic pathways.

A sensitive biosensor with supramolecular architecture was designed and implemented here to detect choline. Choline oxidase and horseradish peroxidase were assembled onto the polymer of thiolated β-cyclodextrin and platinum nanoparticles modified gold electrode through 1-adamantane carboxylic acid coupling. Square wave voltammetry showed that the reduction currents at 0.38 mV had a linear relationship with the logarithms of choline concentrations in the range of 10−9–10−2 M, and the detection limit was down to 0.1 nM. Such biosensor also exhibited excellent selectivity, reproducibility and stability.