Heat-shock reduces wound-induced tissue browning in fresh-cut lettuce by redirecting protein synthesis
M.E. Saltveit , R. Campos-Vargas and H.-M. Kang
Proceedings of 26th International Horticultural Congress. Volume of Abstract . Toronto, Canada, 11-17 August, 2002. Abstract S09-O-125. pp. 254-255.
2002
บทคัดย่อ
Wounding (e.g., fresh-cut lettuce) causes the production and propagation of a signal that induces the de novo synthesis of enzymes associated with phenolic metabolism, the accumulation of phenolic compounds, and subsequent tissue browning. An important enzyme in stress-induced phenolic metabolism is phenylalanine ammonia-lyse (PAL, EC 4.3 1.5). Two wound-induced PALmRNA appear after wounding and before the rise in PAL activity, and give rise to the synthesized PAL. A brief heat shock (45.8 0C for 90 sec.) administered either before or after wounding suppresses the de novo production of PAL and tissue browning. The induced synthesis of specific heat-shock proteins (hsps) correlates with the reduced induction of PAL synthesis. The hsps synthesized in response to a number of stresses are thought to protect the cell from subsequent stresses. However, the exclusive production of hsps in relation to other proteins (e.g., wound-induced PAL) may itself be important. These data supply additional support for the hypothesis that the induced synthesis of hsps interferes with translation of wound-induced PAL mRNA and thereby prevents tissue browning