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V ibrio tapetis is the etiological agent of brown ring disease ( BRD) in clams. Phenotypic, antigenic and genetic variability have been demonstrated, with three groups being established associated with host origin. In this work we analyze the variability of representative strains of these three groups, CECT 4600T and GR0202RD, isolated from Manila clam and carpet-shell clam, respectively, and HH6087, isolated from halibut, on the basis of the whole proteome analysis by 2 D- PAGE and multilocus sequence analysis ( MLSA). A quantitative analysis of the proteome match coefficient showed a similarity of 79% between the clam isolates, whereas fish isolate showed similarities lower than 70%. A preliminary mass spectrometry ( MS) assay allowed the identification of 27 proteins including 50 S ribosomal protein L9, riboflavin synthase β subunit, ribose-phosphate pyrophosphokinase and succinyl- CoA synthase α subunit. The MLSA approach gave similar results, showing a 99.4% similarity of the clam isolates, which was higher than that observed between the fish isolate and either clam strain (98.2%). The topology of the maximum parsimony tree, obtained from 2 D- PAGE analysis, and the phylogenetic tree, constructed with the maximum likelihood algorithm from concatenated sequences of 16 S r RNA gene and five housekeeping genes ( atpA, pyrH, recA, rpoA and rpoD), was very similar, confirming the closer relationship between the two clam isolates. [ABSTRACT FROM AUTHOR]

A complete cDNA from Pinus pinaster Aiton, potentially coding for an alpha-xylosidase able to remove the xylose residue from xyloglucan oligosaccharides, has been cloned. Its sequence was homologous to previously published alpha-xylosidase genes from Arabidopsis and nasturtium. The protein also showed the two signature regions of family 31 of glycosyl hydrolases. The gene expression level was quantified by competitive RT-PCR, under different growth conditions, throughout seedling development, in different regions along the hypocotyls and in auxin-treated hypocotyl segments, and related with growth capacity and alpha-xylosidase activity. A role of alpha-xylosidase in regulating the level of xyloglucan oligosaccharides within the apoplast is proposed. The action of an alpha-xylosidase removing the xylose residue, would make possible the action of a beta-glucosidase deblocking the xyloglucan oligosaccharide degradation and it could serve as a control point for the regulation of the apoplastic levels of xyloglucan oligosaccharides.