The diversity of pathogenesis-related proteins decreases during grape maturation.
It was recently shown that wines contain typically a huge diversity of structurally similar polypeptides that exhibit a high degree of homology to pathogenesis-related (PR) proteins. This observation suggested the existence of one or a few precursors in mature grapes, common to most or all the wine PR proteins. Limited proteolysis and chemical modification of the precursor(s) during fruit ripening and winemaking could then generate the large number of distinct wine polypeptides. However, the patterns of PR proteins extracted from grape berries regularly harvested from the onset of development until maturity did not confirm the previous hypothesis. Two different methodologies, involving 2-D immunoblotting and a combination of FPLC cation/anion exchange chromatographies with 1-D immunoblotting, indicate that the total concentration of PR proteins is increased but its diversity is reduced from the early stages of berry development until maturity. These results indicate that PR proteins are synthesized in a wide variety of forms from the early stages of grape development, eliminating the hypothesis previously formulated on the existence of one or few precursors common to the wine proteins.
Monteiro
Sara
S
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2781-901 Oeiras, Portugal. smonteiro@isa.utl.pt
Piçarra-Pereira
Maria A
MA
Loureiro
Virgílio B
VB
Teixeira
Artur R
AR
Ferreira
Ricardo B
RB
D000595:Amino Acid Sequence; D005638:Fruit; D014644:Genetic Variation; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000633:toxicity*; D016415:Sequence Alignment; D027843:Vitis / Q000254:growth & development*; D014920:Wine
D010940:Plant Proteins