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A report on the production of resveratrol in Escherichia coli by use of a peanut stilbene synthase gene is presented. The data indicates that recombinant yeast expression platform, using the same biosynthetic genes, is not much less efficient than E. coli.

Fruit constitutes a major component of our diet, providing fiber, vitamins, minerals, and many phytonutrients that promote good health. Fleshy fruits such as tomatoes already contain high levels of several of these ingredients. Nevertheless, efforts have been invested in increasing and diversifying the content of phytonutrients, such as carotenoids and flavonoids, in tomato fruits. These efforts rely on transgenic approaches, and the use of single-point mutations and/or quantitative trait loci affecting levels of these phytonutrients. The tomato high pigment (hp) mutations are a good example of the latter alternative. Due to their impact on fruit lycopene content, hp mutations were already introgressed into elite tomato germplasm. Interestingly, plants carrying these mutations are also characterized by higher levels of other health-promoting metabolites, such as flavonoids and vitamins. These mutations were initially marked as lesions in structural genes of the carotenoid biosynthetic pathway. However, recent studies have shown that they represent mutations in two regulatory genes active in light signal transduction, also known as photomorphogenesis. This gene-identification has created a conceptual link between photomorphogenesis and biosynthesis of fruit phytonutrients, and suggests that manipulation of the light signal transduction machinery in plants may be an effective approach towards practical manipulation of fruit phytonutrients. [ABSTRACT FROM AUTHOR]

To take full advantage of the power of functional genomics technologies and in particular those for metabolomics, both the analytical approach and the strategy chosen for data analysis need to be as unbiased and comprehensive as possible. Existing approaches to analyze metabolomic data still do not allow a fast and unbiased comparative analysis of the metabolic composition of the hundreds of genotypes that are often the target of modem investigations. We have now developed a novel strategy to analyze such metabolomic data. This approach consists of (1) full mass spectral alignment of gas chromatography (GC)-mass spectrometry (MS) metabolic profiles using the MetAlign software package, (2) followed by multivariate comparative analysis of metabolic phenotypes at the level of individual molecular fragments, and (3) multivariate mass spectral reconstruction, a method allowing metabolite discrimination, recognition, and identification. This approach has allowed a fast and unbiased comparative multivariate analysis of the volatile metabolite composition of ripe fruits of 94 tomato (Lycopersicon esculentum Mill.) genotypes, based on intensity patterns of »20,000 individual molecular fragments throughout 198 GC-MS datasets. Variation in metabolite composition, both between- and within-fruit types, was found and the discriminative metabolites were revealed. In the entire genotype set, a total of 322 different compounds could be distinguished using multivariate mass spectral reconstruction. A hierarchical cluster analysis of these metabolites resulted in clustering of structurally related metabolites derived from the same biochemical precursors. The approach chosen will further enhance the comprehensiveness of GC-MS-based metabolomics approaches and will therefore prove a useful addition to nontargeted functional genomics research. [ABSTRACT FROM AUTHOR]

• Overall metabolic modifications between fruit of light-hyperresponsive high-pigment (hp) tomato (Lycopersicon esculentum) mutant plants and isogenic nonmutant (wt) control plants were compared.• Targeted metabolite analyses, as well as large-scale nontargeted mass spectrometry (MS)-based metabolite profiling, were used to phenotype the differences in fruit metabolite composition.• Targeted high-performance liquid chromatography with photodiode array detection (HPLC–PDA) metabolite analyses showed higher levels of isoprenoids and phenolic compounds inhp-2 dg fruit. Nontargeted GC–MS profiling of red fruits produced 25 volatile compounds that showed a 1.5-fold difference between the genotypes. Analyses of red fruits using HPLC coupled to high-resolution quadrupole time-of-flight mass spectrometry (LC–QTOF–MS) in both ESI-positive and ESI-negative mode generated, respectively, 6168 and 5401 mass signals, of which 142 and 303 showed a twofold difference between the genotypes.• hp-2 dg fruits are characterized by overproduction of many metabolites, several of which are known for their antioxidant or photoprotective activities. These metabolites may now be more closely implicated as resources recruited by plants to respond to and manage light stress. The similarity in metabolic alterations in fruits ofhp-1andhp-2mutant plants helps us to understand howhpmutations affect cellular processes.New Phytologist(2005)doi: 10.1111/j.1469-8137.2005.01362.x© New Phytologist(2005) [ABSTRACT FROM AUTHOR]

In this paper we review the current literature on antioxidants from fruit of red raspberry (Rubus idaeus) and place these in context concerning what is known from other food species. The review concentrates on the methods of antioxidant testing, the diversity of antioxidants in raspberry, effects of ripeness, cultivar, storage and processing techniques, and the bioavailability of raspberry antioxidants in humans after eating the fruit. It is clear that raspberry, like several other fruits and vegetables such as tomato, strawberry, kiwi and broccoli, represents a valuable contrasting source of potentially healthy compounds and can represent an important component of a balanced diet. [ABSTRACT FROM AUTHOR]

The biosynthesis of flavonoids and proanthocyanidins was studied in cultivated strawberry (Fragaria xananassa) by combining biochemical and molecular approaches. Chemical analyses showed that ripe strawberries accumulate high amounts of pelargonidin-derived anthocyanins, and a larger pool of 3',4'-hydroxylated proanthocyanidins. Activities and properties of major recombinant enzymes were demonstrated by means of in vitro assays, with special emphasis on specificity for the biologically relevant 4'- and 3',4'-hydroxylated compounds. Only leucoanthocyanidin reductase showed a strict specificity for the 3',4'-hydroxylated leucocyanidin, while other enzymes accepted either hydroxylated substrate with different relative activity rates. The structure of late flavonoid pathway genes, leading to the synthesis of major compounds in ripe fruits, was elucidated. Complex developmental and spatial expression patterns were shown for phenylpropanoid and flavonoid genes in fruits throughout ripening as well as in leaves, petals and roots. Presented results elucidate key steps in the biosynthesis of strawberry flavonoid end products.

An octaploid (Fragaria x ananassa cv. Calypso) genotype of strawberry was transformed with an antisense chalcone synthase (CHS) gene construct using a ripening related CHS cDNA from Fragaria x ananassa cv. Elsanta under the control of the constitutive CaMV 35S promoter via Agrobacterium tumefaciens. Out of 25 transgenic lines, nine lines showed a reduction in CHS mRNA accumulation of more than 50% as compared to the untransformed cv. Calypso control. The antisense CHS construct was found to be integrated into the genome, with a copy number ranging from one to four. The pigmentation of the fruit was only affected when less than 5% of the control CHS expression level was detected. A stable antisense phenotype over a period of 4 years was obtained in the primary transgenic lines at a rate of 1:20. As a consequence of the reduced activity of CHS, the levels of anthocyanins, flavonols, and proanthocyanidins were downregulated and precursors of the flavonoid pathway were shunted to the phenylpropanoid pathway leading to highly increased levels of cinnamoyl glucose (520% of control), caffeoyl glucose (816% of control), and feruloyl glucose (1092% of control) as well as p-coumaryl alcohol (363% of control) and p-coumaryl-1-acetate (1079% of control), which occur only as trace components in untransformed control fruits. These results demonstrate that the introduction of an antisense CHS construct in strawberry results in an unpredictable biochemical phenotype, thereby confirming that CHS function is an important regulatory point of substrate flow between the flavonoid and the phenylpropanoid pathways.

As one of the main phytoalexins and phytoestrogens, glyceollin is an important prenylflavonoid in Glycine max [L.] Merri. (soybean). Many kinds of elicitors can be used to induce its accumulation. Its biosynthesis pathway is commonly used to study the characteristics of prenyltransferase, which catalyzes the prenylated reaction happening in a very few plant families in nature. Glycinol, the direct precursor of glyceollin, is necessary to study the prenylated reaction in soybean. In comparing with the other elicitors to elicit the glycinol accumulation in soybean cotyledons, AgNO3 is the most effective elicitor. Exposure of 6-8 days old cotyledons to 0.01 mol/L AgNO3 and incubation for 24 h result in the accumulation of 256 microg (glycinol)/g (fresh weight). The glycinol was extracted by methanol. Then the isolation and purification were conducted by preparative high performance liquid chromatography. Instead of 100% acetonitrile-0.1% formic acid as the elution system, the extract was eluted by 100% methanol-0.1% formic acid. Glycinol eluted earlier than daidzin under this system and decreased the disturbance from the large amount of daidzin. Identification was performed by comparing the mass spectrum (liquid chromatography/quadrupole-time of flight) and ultraviolet spectrum with those of the standard. At last, 100 mg purified glycinol was obtained from 390 g of fresh material.