Flesh softening and phosphorylation of soluble polypeptides in relation to ethylene production in peach fruits with different ripening patterns.
Morgutti S., Negrini N., Nocito F.F., de Nucci E., Mignani I., Bassi D., Cocucci M.
5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004. page 10
2004
บทคัดย่อ
In peaches, it is desirable to individuate simple biochemical/physiological parameters, genetically determined and thus useful for Marker-Assisted Selection to obtain improved genotypes for what concerns flesh firmness (Melting/Non-Melting).The expression of enzymes involved in cell wall loosening/degradation, such as expansins (Exp) and endo-polygalacturonases (endo-PGs) has been studied in peach fruits of a few M, MN, Slow-Ripening genotypes available in
In M fruits, the expression in the flesh cell walls of an endo-PG-like polypeptide was relevant and increased with ripening.The polypeptide was expressed at very low extent in NM fruits.A similar pattern was observed for expansins (assessed with anti-LeExp1 antibodies kindly supplied by dr. J.K.C. Rose).NM fruits produced more ethylene than the M ones.The Ca+2 –dependent phosphorylation pattern of a soluble polypeptide (Mr 52 kDa) from the fruit flesh showed differences related to ripening stage and phenotype.It decreased with ripening in NM fruits whereas it remained constant in the M ones.In slow ripening genotypes, with mutated ripening pattern, the phosporylation of the 52 kDa soluble plolypeptide was detectable only in those fruits which, though not achieving the normal size, produced ethylene, expressed the endo-PG-like polypeptide and softened their flesh.
These data suggest that the degree of phophorylation of the 52 kDa soluble polypeptide may be involved in the modulation of ethylene signal and may possibly be linked to a higher sensitivity to ethylene in M fruits.