alfa-Arabinofuranosidase (alfa-Ara) in strawberry fruit: Enzyme activity and expresi¨®n of related genes in cultivars with contrasting firmness

ROSLI HG; PEDRO MARCOS CIVELLO; MARTÍNEZ GA

Pinamar, Pcia. Buenos Aires

Congreso; 10th Congress of PABMB (Panamerican Association for Biochemistry and Molecular Biology); 2005

PABMB y SAIB

PL-P26. ¦Á-ARABINOFURANOSIDASE (¦Á--ARA) IN STRAWBERRY FRUIT: ENZYME ACTIVITY AND EXPRESSION OF RELATED GENES IN CULTIVARS WITH CONTRASTING FIRMNESS Rosli H, Civello M, Mart¨ªnez G. IIB-INTECH, UNSAM-CONICET, Camino Laguna Km 6, (B7130IWA), Chascom¨²s, Pcia. Buenos Aires, Argentina. E-mail:hrosli@intech.gov ar Fruit softening is accompanied by cell wall modification leading to solubilization and depolimerization of its components. Cell wall disassembly is mediated by several proteins. Arabinose, is one of the most abundant neutral sugar in strawberry and it is also the one showing the largest decrease during ripening. ¦Á-ARA catalyzes the hydrolysis of arabinose residues present in pectin and hemicellulose side chains. In this work, we report for the first time the presence of ¦Á-ARA in strawberry and the cloning of three putative ¦Á--ARA encoding genes. We analysed ¦Á-ARA activity during ripening of strawberry cultivars with contrasting fruit firmess. The softest cultivar showed higher activity levels and the activity increased throughout ripening. A partial purified sample was analyzed in a Sephacryl S100 column and a peak corresponding to 70 KDa was found. We screened a ripe fruit cDNA library using degenerate primers and found three putative a-ARA full length clones. Semi quantitative RT-PCRs were carried out to investigate the expression of these genes during fruit ripening and in different tissues.