Effect of plant regulators on the expression of BoPaO and BoLOX 1 during senescence of broccoli

GÓMEZ LOBATO, MARÍA EUGENIA; CIVELLO, MARCOS; MARTÍNEZ, GUSTAVO

Tucuman

Congreso; XLV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2009

Plant senescence involves several events that occur at the final stages of development, or are initiated in response to a stress. The characteristics symptom is the loss of green color caused by chlorophyll degradation. Broccoli (Brassica oleracea) is a vegetable belonging to the group of Coles, included in the family of Cruciferae. Broccoli is harvested when their inflorescences are still immature, which causes considerable stress and triggers the senescence. In this work, it was studied by RT-PCR the effect of different plant regulators on the expression of two genes normally associated to senescence: Pheophorbide a oxygenase (PaO), involved in chlorophyll degradation and Lipoxygenase 1 (LOX 1), associated to lipid degradation and to the synthesis of jasmonic acid. Broccolis were treated with cytokine and ethylene, in order to delay or accelerate senescence, respectively. It was observed that, after three days, the expression of PaO decrease significantly in both treatments. After 5 days, samples treated with ethylene increased the expression of PaO over control while cytokine treated samples showed a decrement of almost 50% in PaO expression. In the case of LOX1, it was observed that the expression significantly decreased in both treatments after 3 days. However, treatment with ethylene increased the expression of LOX1 while cytokine did not affect this expression after 5 days.