Purification and characterization of a jacalin-related protein from sunflower apoplast

ELIZALDE MERCEDES; REGENTE MARIANA; PINEDO MARCELA; DE LA CANAL LAURA

San Miguel de Tucumán

Congreso; XLV Reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2009

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The proteomic analysis of apoplastic fluids (AFs) from sunflower seeds and seedlings let us the tentative identification of a 16 kDa band as a Jacalin-Related Protein (JRP).  These plant lectins display a typical intracellular location and mannose or galactose affinity. The bioinformatic analysis of the matched sequence, a Helianthus tuberosus JRP, showed that it has a mannose binding motif and no signal peptide to enable its secretion. Purification of AFs on a mannose-agarose affinity matrix and MALDI/TOF-TOF MS confirmed the in silico assigned identity. Additionally the affinity purified fraction was able to agglutinate yeast and tomato cells. Polyclonal antibodies against the protein were obtained and used in immunoanalysis of sunflower seeds and seedlings. We obtained evidences that its content decreased through the germination being almost undetectable in 10 days-old seedlings. Furthermore, it remained unchanged in seeds incubated with 500 µM ABA or 100 µM Jasmonic Acid. We can conclude that the protein from sunflower AFs is a novel member of the mannose-binding JRP group with extracellular location.