Abstract
Given that calmodulin (CaM), phospholipase D (PLD), and 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) play important roles in plant stress response, we investigated the expression of CaM-encoding genes, BoCam1 and BoCam2, PLD-encoding genes, BoPLD1 and BoPLD2, and ACS-encoding gene, BoACS2, in wounded cabbage (Brassica oleracea var. Capitata L.) leaf disk obtained from the first layer of the head using a cork borer. Normalized with the internal standard, quantitative real-time PCR revealed that wounding treatment significantly elevated BoCam1 levels, with the highest level occurring 60 min after treatment (6.4 fold). Although BoCam2 expression levels were low, a significant increase was also detected at 60 min (1.6 fold). For PLD-encoding genes, the expression level of BoPLD1 was only 1.5-fold greater 120 min after treatment. The expression of BoPLD2 also remained low, and no clear differences were observed among treatments during the investigation. Additionally, the expression level of BoACS2 decreased at 15 min to 30 min and then its level rose again to 1.6-fold at 120 min after treatment. However, the expression level of BoACS2 remained low during the investigation. Overall, BoCam1 is likely a wound-responsive gene that is induced to high expression levels after encountering stress. Moreover, because of its high sensitivity to the wounding stress, BoCam1 should be taken into consideration in further study of postharvest mechanical stress as it may be associated with the signaling cascade and cellular stress response in cabbage.
