Changes in alpha-xylosidase during intact and auxin-induced growth of pine hypocotyls.
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.
Sánchez
María
M
Departamento de Fisiología Vegetal, Facultad de Biología, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
Gianzo
Cristina
C
Sampedro
Javier
J
Revilla
Gloria
G
Zarra
Ignacio
I
D000595:Amino Acid Sequence; D018546:Hypocotyl / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D007210:Indoleacetic Acids / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D028223:Pinus / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014995:Xylosidases / Q000235:genetics / Q000378:metabolism*
D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014995:Xylosidases