In soybean (Glycine max L.), pathogen attack induces the formation of glyceollin-type phytoalexins. The biosynthetic key enzyme is a reductase which synthesizes 4,2',4'-trihydroxychalcone in co-action with chalcone synthase. Screening of a soybean cDNA library from elicitor-induced RNA in , I gtll yielded two classes of reductase-specific clones. The deduced proteins match to 100% and 95%, respectively, with 229 amino acids sequenced in the purified plant protein. Four clones of class A were expressed in Escherichia coli, and the proteins were tested for enzyme activity in extracts supplemented with chalcone synthase. All were active in 4,2',4'-trihydroxychalcone formation, and the quantification showed that shorter lengths of the cDNAs at the 5' end correlated with progressively decreasing enzyme activities. Genomic blots with DNA from plants capable of 4,2',4'-trihydroxychalcone synthesis revealed related sequences in bean (Phaseolus vulgaris L.) and peanut (Arachis hypogaea L.), but not in pea (Pisum sativum L.). No hybridization was observed with parsley (Petroselinum crispum) and carrot (Daucus carota) which synthesize other phytoalexins. The reductase protein contains a leucinezipper motif and reveals a marked similarity with other oxidoreductases most of which are involved in carbohydrate metabolism.

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1-mm particle sizes, and subjected to NIRS to measure quality parameters. Near-infrared spectroscopy can rap-Improving maize (Zea mays L.) forage yield and quality is a major idly measure multiple traits in food and agricultural goal for corn breeders in northern Europe. The objective of this research was to measure maize forage dry matter (DM) content and rope GmbH, Res. & Product Dev.,

Enzyme synthesis of 6'-deoxychalcone from 4-coumaroyl-CoA and malonyl-CoA has been achieved, using purified soybean chalcone synthase (CHS), NADPH and a further protein (reductase). This reductase was purified to apparent homogeneity by a procedure including affinity chromatography on Blue Sepharose and elution with NADP+. This enzyme has a molecular mass of about 34 kDa and consists of a single polypeptide. Synthesis of deoxychalcone also occurred with parsley CHS, NADPH and the soybean reductase. The reductase catalyzed transfer of the pro-R hydrogen of[42H]NADPH to the substrate.

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