Controlled atmosphere (CA) treatment of broccoli after harvest delays senescence and induces the expression of novel BoCAR genes
J.R. Eason, E.C. de Guzman, B. Page, P. West
Program and Abstract. 2007 Australasian Postharvest Conference. Crowne Plaza Terrigal, NSW, Australia. 12 September 2007. 87 p.
2007
บทคัดย่อ
The transcription of four genes (BoCAR1A, BoCAR5, BoCAR6-4 and BoCAR25) is up-regulated in response to CA treatment in broccoli (Brassica oleracea). Physiological and biochemical changes and gene expression patterns were examined in broccoli tissues held in one of different atmospheres, namely air (< 1% CO2, 21% 02), high carbon dioxide and low oxygen (CA:10% CO2, 5% 02), low oxygen (0% CO2, 5% 02), and high carbon dioxide (10% CO2, 20% 02). Gene expression was also examined in tissues held for short periods in CA (< 24 h) followed by air. In addition, we examined whether CA treatment was effective in up-regulating these CA-responsive genes and delaying senescence after early senescence-associated gene changes had been initiated by exposing broccoli tissues to CA after 48 h in air. Molecular analysis showed that a combined high CO2 and low 02 atmosphere was more effective than high CO2 or low 02 alone for inducing maximum gene expression and delaying postharvest broccoli senescence. In addition, broccoli tissues responded to CA treatment after a 48 h period in air with increased CA-responsive gene expression. BoCAR transcription was not elevated in tissues exposed to stresses that promoted senescence (e.g. salt and water stress), or in tissues treated with cytokinin, a treatment known to delay the onset of postharvest senescence in broccoli. The expression of one gene (BoCAR6-4) appears to be specific to CA treatment in harvested broccoli tissues.