No abstract

In some European community countries up to 8% of the agricultural area is managed organically. The aim was to obtain a metabolite profile for wheat (Triticum aestivum L.) grains grown under comparable organic and conventional conditions. These conditions cannot be found in plant material originating from different farms or from products purchased in supermarkets. Wheat grains from a long-term biodynamic, bioorganic, and conventional farming system from the harvest 2003 from Switzerland were analyzed. The presented data show that using a high throughput GC-MS technique, it was possible to determine relative levels of a set of 52 different metabolites including amino acids, organic acids, sugars, sugar alcohols, sugar phosphates, and nucleotides from wheat grains. Within the metabolites from all field trials, there was at the most a 50% reduction comparing highest and lowest mean values. The statistical analysis of the data shows that the metabolite status of the wheat grain from organic and mineralic farming did not differ in concentrations of 44 metabolites. This result indicates no impact or a small impact of the different farming systems. In consequence, we did not detect extreme differences in metabolite composition and quality of wheat grains.

Xyloglucan endotransglycosylase (XET) from the core tissue of ripe kiwifruit (Actinidia deliciosa [A.Chev.] C.F. Liang et A.R. Ferguson var. deliciosa cv. Hayward) was puri®ed 3000-fold to homogeneity. The enzyme has a molecular weight of 34 kDa, is N-glycosylated, and is active between pH 5.0 and 8.0, with an optimum between 5.5 and 5.8. The K m was 0.6 mg á mL A1 for kiwifruit xyloglucan and 100 lM for [ 3 H]XXXG-ol, a reduced heptasaccharide derived from kiwifruit xyloglucan. Kiwifruit core XET was capable of depolymerising xyloglucan in the absence of [ 3 H]XXXGol by hydrolysis, and in the presence of [ 3 H]XXXG-ol by hydrolysis and endotransglycosylation. Six cDNA clones (AdXET1-6) with homology to other reported XETs were isolated from ripe kiwifruit mRNA. The six cDNA clones share 93±99% nucleotide identity and appear to belong to a family of closely related genes. Peptide sequencing indicated that ripe kiwifruit XET was encoded by AdXET6. Northern analysis indicated that expression of the AdXET1-6 gene family was induced in ripening kiwifruit when endogenous ethylene production could ®rst be detected, and peaked in climacteric samples when fruit were soft. A full-length cDNA clone (AdXET5) was overexpressed in E. coli to produce a recombinant protein that showed endotransglycosylase activity when refolded.The Genbank accession number of the AdXET5 clone reported in this paper is L46792 Abbreviations: Con A = concanavalin A; XET = xyloglucan endotransglycosylase; FPLC = fast protein liquid chromatography; IPTG = isopropyl b-D-thiogalactopyranoside; kgf = kilogram ®rmness; PCR = polymerase chain reaction; SSC = 150 mM NaCl, 15 mM tri-sodium citrate; XXXG-ol = reduced xyloglucan-derived heptasaccharide

Plastid lipid-associated proteins, also termed fibrillin/CDSP34 proteins, are known to accumulate in fibrillar-type chromoplasts such as those of ripening pepper fruit, and in leaf chloroplasts from Solanaceae plants under abiotic stress conditions. It is shown here that treatments generating active oxygen species (high light combined with low temperature, gamma irradiation or methyl viologen treatment) result in potato CDSP34 gene induction and protein accumulation in leaves. Using transgenic tomato plants containing the pepper fibrillin promoter, a significant increase in promoter activity in leaves subjected to biotic stress, namely bacterial infections, was observed. In WT, a higher level of the endogenous fibrillin/CDSP34 protein is also observed after infection by E. chrysanthemi strain 3739. In addition to stress-related induction, a progressive increase in the fibrillin promoter activity is noticed during ageing in various tomato photosynthetic tissues and this increase correlates with a higher abundance of the endogenous protein in WT leaves. It is proposed that a mechanism related to oxidative events plays an essential role in the regulation of fibrillin/CDSP34 genes during stress and also during development. Using a biolistic transient expression assay, the pepper fibrillin promoter is found to be active in various dicot species, but not in monocots. Further, substantially increased levels of fibrillin/ CDSP34 proteins are shown in various dicotyledonous and monocotyledonous plants in response to water deficit.

Motivation: The research area metabolomics achieved tremendous popularity and development in the last couple of years. Owing to its unique interdisciplinarity, it requires to combine knowledge from various scientific disciplines. Advances in the high-throughput technology and the consequently growing quality and quantity of data put new demands on applied analytical and computational methods. Exploration of finally generated and analyzed datasets furthermore relies on powerful tools for data mining and visualization.Results: To cover and keep up with these requirements, we have created MeltDB 2.0, a next-generation web application addressing storage, sharing, standardization, integration and analysis of metabolomics experiments. New features improve both efficiency and effectivity of the entire processing pipeline of chromatographic raw data from pre-processing to the derivation of new biological knowledge. First, the generation of high-quality metabolic datasets has been vastly simplified. Second, the new statistics tool box allows to investigate these datasets according to a wide spectrum of scientific and explorative questions.Availability: The system is publicly available at https://meltdb.cebitec.uni-bielefeld.de. A login is required but freely available.Contact: nkessler@cebitec.uni-bielefeld.de

We present phylogenetic analyses to demonstrate that there are three families of sucrose phosphate synthase (SPS) genes present in higher plants. Two data sets were examined, one consisting of full-length proteins and a second larger set that covered a highly conserved region including the 14-3-3 binding region and the UDPGlu active site. Analysis of both datasets showed a well supported separation of known genes into three families, designated A, B, and C. The genomic sequences of Arabidopsis thaliana include a member in each family: two genes on chromosome 5 belong to Family A, one gene on chromosome 1 to Family B, and one gene on chromosome 4 to Family C. Each of three Citrus genes belong to one of the three families. Intron/exon organization of the four Arabidopsis genes differed according to phylogenetic analysis, with members of the same family from different species having similar genomic organization of their SPS genes. The two Family A genes on Arabidopsis chromosome 5 appear to be due to a recent duplication. Analysis of published literature and ESTs indicated that functional differentiation of the families was not obvious, although B family members appear not to be expressed in roots. B family genes were cloned from two Actinidia species and southern analysis indicated the presence of a single gene family, which contrasts to the multiple members of Family A in Actinidia. Only two family C genes have been reported to date.

For the Fusarium trichothecene mycotoxins T-2 and HT-2, a combined (T-2 + HT-2) temporary tolerable daily intake (tTDI) of 0.06 microg kg(-1) body weight day(-1) was proposed at the European level in 2001 (Opinion of the Scientific Committee on Food). In the near future, maximum levels for these trichothecenes will be regulated by the European Commission as announced in EU (VO) 1881/2006. For the implementation of these maximum levels, more data on occurrence and behaviour of T-2 and HT-2 toxins in primary agricultural products as well as during cleaning treatment and food processing are needed. In the current work, we determined the T-2/HT-2 concentrations in four oat cultivars (Aragon, Dominik, Ivory, Pergamon) from ten different agricultural sites in Germany, grown in cultivar studies in 2007. The grains were de-hulled, oat meal was prepared, and bread with 20% oat meal and 80% wheat flour was baked. In the cereal-processing chain, samples were taken at various steps and subsequently analysed for their T-2/HT-2 content. We employed liquid chromatography-mass spectrometry (LC-MS) and an immunological screening method (enzyme-linked immunoabsorbent assay (ELISA)) for T-2/HT-2 determination. Detection limits were between 1 and 10 microg kg(-1) in different matrices. T-2/HT-2 concentrations determined by ELISA in oat samples from ten different agricultural sites in Germany were between 9 and 623 microg kg(-1). The median and 90th percentile were 48 and 191 microg kg(-1) T-2/HT-2, respectively. One site showed six times higher T-2/HT-2 levels than the other sites, where concentrations ranged from 322 to 623 microg kg(-1). In 80% of the samples the cultivars Pergamon and Ivory had the lowest concentration of T-2 and HT-2 toxins. Using LC-MS for T-2/HT-2 determination, cleaning of the raw material did not lead to significant reductions of T-2 and HT-2 levels, whereas de-hulling led to a reduction of over 90%. Boiling of oat meal produced from cleaned raw material to yield 'porridge' resulted in varying T-2/HT-2 levels in experimental replicates. No major reduction of T-2/HT-2 levels in cooked porridge was obtained. Standardized baking experiments using 20% oat meal showed that T-2 and HT-2 toxins are relatively stable during the baking process, probably due to their temperature stability.

Based on individual cultivars, metabolite profiling showed promising results for the categorization of organic and conventional wheat. Further investigations are necessary with wheat from more growing seasons and locations before definite conclusions can be drawn concerning the feasibility to evolve a combined set of biomarkers for organically grown wheat using metabolite profiles.