Effect of 1-MCP on the expression of chlorophyll degrading genes during senescence of broccoli

GÓMEZ LOBATO, ME; HASPERUÉ, J; CIVELLO PM; MARTÍNEZ, GA

Potrero de los Funes, San Luis

Congreso; XLVII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2011

Plant senescence involves several events that occur at the final stages of development, or are initiated in response to stress. The loss of green colour caused by chlorophyll degradation is the most characteristics symptom. Broccoli (Brassica oleracea) belongs to the family of Cruciferae. It is harvested when inflorescences are immature, which causes considerable stress and triggers the senescence. In this work, we studied the effect of 1-MCP, an ethylene inhibitor agent, on the expression by RT-PCR of genes associated to chlorophyll degradation pathway: Chlorophyllase 1 (BoCHL1), Chlorophyllase 2 (BoCHL2), Pheophytinase (BoPPH) and Pheophorbide a oxigenase (BoPaO). Broccoli heads were treated with 1-MCP and stored in dark at 22 ºC for five days. The relative expression of BoCLH1 decreased continuously during senescence in both control and treated samples. In the case of BoCLH2, the expression increased after 72 h and then diminished after 120 h in controls, whereas in 1-MCP treated samples the expression were higher than controls at 72 h without decreasing afterwards. The relative expression of BoPPH increased after 72 h and then diminished in controls. The treatment with 1-MCP induced the peak of BoPPH expression after 120 h. The expression of BoPaO was similar to that of BoPPH and BoCHL2 in controls. The treatment did not modify this pattern but the relative expression was lower.