Polygalacturonase on strawberry fruit ripening. Effects of plant growth regulators.

VILLARREAL NM; MARTÍNEZ GA; CIVELLO PM

Córdoba

Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular.; 2008

SAIB

Strawberry (Fragaria x ananassa Duch.) is a fleshy fruit that undergoes extensive softening during ripening as a consequence of cell wall disassembly caused by a coordinated action of cell wall hydrolases, including polygalacturonases (PGs). Nowadays there is not a global understanding about the hormonal regulation of strawberry ripening and softening. In this work, the immuno-detection, by Western blot assays, of PG protein (FaPG1) during ripening of strawberry cultivars with contrasting firmness is reported. The purified antibody recognized two proteins with molecular mass around 45-50 kDa. The accumulation of FaPG1 in the softest cultivar (Toyonaka) began at white stage y remained high until the end of ripening. In the firmer cultivar (Camarosa) the accumulation of FaPG1 was low at 25 % red stage and increased at 50 % and 100 % red. The presence of two immunoreactive bands is apparently due to differential glicosylation of one polypeptide. In addition, the effect of different plant growth regulators on FaPG1 protein accumulation was analyzed. The treatment with naphtalen acetic acid and gibberelins delayed ripening and anthocyanin accumulation, and reduced the accumulation of FaPG1 proteins. On the other hand, it was detected a higher level of anthocyanins and FaPG1 synthesis in fruit treated with abscisic acid, ethylene and NO.