Influence of UV-C irradiation on expansin and pectin-methylesterase gene expression in strawberry fruit

POMBO MA; DOTTO MC; MARTÍNEZ GA; CIVELLO, PM

Pinamar, Pcia. Buenos Aires, República Argentina.

Congreso; 10th Congress of PABMB (Panamerican Association for Biochemistry and Molecular Biology); 2005

Panamerican Association for Biochemistry and Molecular Biology;Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The exposure to UV-C delays fruit softening, one ofthe main factors determining fruit postharvest life. This delay in softening may be caused by changes in the activities of enzymes and proteins involved in cell wall disassembly. Expansins are cell wall proteins involved in fruit softening, while pectin-methylesterases (PME) are cell wall enzymes related to pectin demethylation, and their activity is affected by heating, another physical treatment based on abiotic stress. We analyzed FaPM1gene expression in irradiated strawberry fruits and also measured PME activity after treatment. An increase in PME activity immediately after the treatment was found. The expression ofFaEXP2, FaEXP4 and FaEXP5 genes was analyzed in the same fruit samples, as well as expansin protein acumulation. For these three genes we found a decrease in expression 4 h after treatment and an increase after 24 h. The decrease in gene expression after treatment correlated with a diminution of expansins.