The metabolomic approach to the assessment of cultivar specificity of Brassica napus L. seeds

Recent biomolecular studies tend to involve combinations of different methods and approaches that allow analyzing organisms on the genomic and proteomic levels, as well as on the level of metabolomics. However, in order to justify the use of the metabolomics techniques in plant breeding, it is important to perform comprehensive analysis of a broad range of species and varieties. In this study, we evaluated the contents of low-molecular-weight substances in seeds of different rapeseed cultivars by the gas chromatography–mass spectrometry (GC-MS) technique. For every metabolomic profile, we estimated 168 target substances, and 52 of them were unambiguously identified. These compounds included amino acids, organic and fatty acids, tocopherols, and phytosterols. In order to keep the data assay within the context of multivariate statistics, we used principal component analysis (PCA), partial least square discriminant analysis (PLS-DA), and partial least square regression (PLS-R). Subsequent analysis revealed a significant difference between the metabolomic profiles of the investigated rapeseed cultivars, with the primary role of the amino acids and organic acids. Noticeably, the PLS-DA model showed 65% of the explained variance and, according to the Venetian blinds cross- validation test, 91.67 % of the accuracy. Thus, we demonstrate the effectiveness of the metabolomics approach to the varietal identification of seeds. This strategy can be further improved with a continuously updated database of the metabolomic profiles of different species and cultivars. Application of the PLS-DA method will allow comparison of the metabolites of unknown samples with the existing profiles and, subsequently, identification of new seed samples

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Serological and molecular characterization of Vibrio parahaemolyticus marine strains carrying pandemic genetic markers

Abstract In 2005, pandemic Vibrio parahaemolyticus was reported to have been introduced in Europe: O3:K6 strains were isolated from clinical cases in France and Spain, and were found to be associated with consumption of contaminated seafood. On the contrary, pandemic strains were not isolated from seafood or from the environment itself. Analysis of two V. parahaemolyticus strains isolated in May 2007 from Northern Italy seawater and plankton samples revealed the presence of the virulence gene tdh and the pandemic-specific markers orf8 and toxRS/new sequence (group-specific PCR). The two strains showed serotypes not included in the 'pandemic group', but their molecular typing proved that they represent a single clone showing a genetic profile very similar to that of pandemic O3:K6 reference isolates. Moreover, the two marine strains carried three virulence-related genes associated with clinical strains and, to date, hardly ever or never detected in environmental strains. The presence, in strains isolated from the marine environment, of genetic pandemic markers and virulence genes normally associated with clinical isolates proves that marine strains might constitute a public health concern