INSTITUTO DE FISIOLOGIA VEGETAL
Unidad Ejecutora - UE
Analysis of the expression of a gene encoding a lipoxygenase (BoLOX1) during postharvest senescence of broccoli
GÓMEZ LOBATO, MARIA EUGENIA; CIVELLO, PEDRO MARCOS; MARTÍNEZ, GUSTAVO
POSTHARVEST BIOLOGY AND TECHNOLOGY
ELSEVIER SCIENCE BV
Año: 2012 vol. 64 p. 146 - 146
Lipoxygenases (LOX) belong to a large family of plant enzymes that catalyze the hydroperoxidation ofpolyunsaturated fatty acids. Most of them are expressed during senescence and contribute to membranedeterioration and biosynthesis of jasmonic acid, a known senescence enhancer. In this work, we cloneda fragment of a gene encoding a LOX from broccoli (BoLOX1). The analysis of the sequence revealed thatBoLOX1 is closely related to other LOX from higher plants. Furthermore, we analyzed the expression ofBoLOX1 and detected a larger increase during postharvest senescence. A slight increase of total lipoxygenaseactivity was also found during senescence. In other sets of experiments, broccoli heads were treatedwith plant hormones, such as cytokinin and ethylene, as a way to assess the effect of such compoundson the expression of BoLOX1. Cytokinin treatment delayed the increase of BoLOX1 expression and lipoxygenaseactivity whereas ethylene accelerated both processes. Also, several postharvest treatments wereapplied in order to delay senescence in broccoli florets and to evaluate their effects on BoLOX1 expression.Samples treated with modified atmosphere, hot air, UV-C or white light showed a delay in chlorophylldegradation and degreening. In most cases, the treatments also delayed the increase of BoLOX1 expression,reaffirming the relationship between the expression of this gene and senescence. However, treatmentslike modified atmospheres and visible light markedly increased lipoxygenase activity, which suggests alack of correlation between BoLOX1 expression and lipoxygenase activity.