ISHS Acta Horticulturae 682: V International Postharvest Symposium
FLESH SOFTENING AND PHOSPHORYLATION OF SOLUBLE POLYPEPTIDES IN RELATION TO ETHYLENE PRODUCTION IN PRUNUS PERSICA FRUITS WITH DIFFERENT RIPENING PATTERNS |
| Authors: | S. Morgutti, N. Negrini, I. Mignani, D. Bassi, M. Cocucci |
| Keywords: | cell wall proteins, endo-PGs, expansins, Prunus persica, Western blotting |
| Abstract:
In peach fruit, it is desirable to individuate simple biochemical/physiological parameters, genetically determined and useful for marker-assisted selection to obtain improved genotypes for flesh firmness. The accumulation of proteins involved in cell wall re-organisation, such as endo-polygalacturonases (endo-PGs) and expansins, has been studied in fruits of two genotypes with either Non-Melting- (NMF) or Melting Flesh (MF) texture, and in fruits of three ‘Slow-Ripening’ (‘SR’: altered ripening pattern) genotypes. In the flesh cell walls of MF fruits, the amounts of an endo-PG-like polypeptide were relevant and increased with ripening, while it was produced in extremely low amounts in NMF fruits. A similar pattern was observed for expansins. NMF fruits produced more ethylene than the MF ones. The Ca2+-dependent phosphorylation of a soluble polypeptide (Mw ≈ 52 kDa) decreased with ripening in NMF fruits and remained constant in the MF ones. In ‘SR’ genotypes, phosphorylation of this polypeptide was detectable only in ethylene-producing fruits, which softened their flesh and expressed the endo-PG-like polypeptide. The data suggest that phosphorylation of the 52-kDa polypeptide may be involved in the modulation of ethylene signalling and flesh softening. | |
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