Induction of Phenylalanine Ammonia Lyase in strawberry fruit by UV-C treatment

MARINA A. POMBO; GUSTAVO A. MARTÍNEZ; PEDRO M. CIVELLO

Mar del Plata, Argentina

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Bioquímica y Biología Molecular (SAIB); 2007

Phenylalanine ammonia lyase (PAL) is a key enzyme in the shikimic acid pathway, which derives partially in the accumulation of anthocyanin pigments, determining strawberry fruit quality. On the other hand, the mentioned pathway is linked to the accumulation of phytoalexins and the formation of lignin-like polymers, both associated with fruit resistance to pathogenic fungi. It has been demonstrated in several fruits that the treatment with low doses of UV-C light (hormesis), induces the synthesis of a number of anti-fungal compounds in the fruit, like phytoalexins, peroxidase enzymes, PR-proteins (chitinases and beta-1,3-glucanases) and PAL. In this work, we have designed specific primers to generate 249 bp strawberry PAL gene fragment by PCR amplification. This gene fragment was used as a probe to analyze PAL expression in control and UV-C irradiated fruit at several times after the treatment. We found an increased PAL expression at 4, 18 and 24 h after the irradiation. We also studied PAL enzyme activity and observed the same pattern than in the gene expression, with an increase in the irradiated fruit even 48 h after the treatment.