HPLC separation of glucosinolates from leaves and seeds of Arabidopsis thaliana and their identification using thermospray liquid chramatography/mass spectrometry

Leaf and seed extracts of Arabidopsis thaliana var. Columbia contain a large number of glucosinolates, representing close to 25% of those known to occur in nature. The glucosinolates, in the form of their desulphated analogs, are separated by reversed-phase, high-performance liquid chromatography (HPLC). Seventeen are identified using thermospray liquid chromatography/mass spectrometry (TSP LC/MS). Additional glucosinolates, present in trace amounts, are identified as isothiocyanates by electron impact and chemical ionization gas chromatography/MS (GC/MS). In total, 23 glucosinolates are detected and these include four series of homologs and analogs. Fifteen possess aliphatic side chains, of which six contain \u3c9-methylthioalkyl and six contain \u3c9-methylsulphinylalkyl side chains; eight possess aromatic side chains, of which four constitute an homologous series of benzoic acid esters and three possess 3-indolylmethyl-based structures. Sixteen of the glucosinolates are detected in Arabidopsis thaliana for the first time and three of these, 4-hydroxybutyl glucosinolate, 5-benzoyloxypentyl glucosinolate, and 6-benzoyloxyhexyl glucosinolate, represent novel plant constituents.Peer reviewed: YesNRC publication: Ye

Isolation and molecular characterization of the arabidopsis TPS1 gene, encoding trehalose-6-phosphate synthase

An Arabidopsis thailana cDNA clone, AtTPS1, that encodes a trehalose-6-phospheta synthase was isolated. The identity of this protein is supported by both structural and functional evidence. On one hand, the predicted sequence of the protein encoded by AtTPS1 showed a high degree of similarity with trehalose-6-phosphate syntheses of different organisms. On the other hand, expression of the AtTPS1 cDNA in the yeast tps1 mutant restored its ability to synthesize trehalose and suppressed its growth defect related to the lack of trehalose-6-phosphate. Genomic organization and expression analyses suggest that AtTPS1 is a single-copy gens and is expressed constitutively at very low levels