The Effect of Methyl Jasmonate on Postharvest Quality and Expression of RhLAC and RhPIP2 Genes in Cut Rose, ‘Red Alert’

Adverse conditions during pre- and postharvest stages affect the longevity and quality of horticultural crops. Thus, storage conditions should be considered in marketing management, especially for cut flowers. Methyl jasmonate is a well-known signaling molecule involved in plant defense responses. Applying it as a treatment can effectively prolong the vase life of horticultural crops. The expression of Laccase gene, acting downstream of the ethylene signal transduction, can be induced by exogenous ethylene. The PIP2 gene is a major group of plasma membrane proteins that are linked to aquaporin channels. This study explored the effect of methyl jasmonate on postharvest quality and expression LAC and PIP2 genes of cut rose, cv. ‘Red alert’. The results showed that methyl jasmonate improved the vase life of cut roses, although it was most effective at 0.2 µl L-1. An analysis of antioxidant enzymes indicated that the highest catalase activity and peroxidase activity occurred in response to 0.2 µl L-1 and 0.2-0.3 µl L-1 methyl jasmonate, respectively, although both enzymes showed a decreasing trend during the vase life period. Proline levels increased significantly in response to 0.2 and 0.3 μl L-1 methyl jasmonate concentr-ations. Quantitative PCR analysis showed that all concentrations of methyl jasmonate significantly reduced the expression of PIP2 and LAC genes. The lowest expression level of PIP2 and LAC genes occurred in response to 0.2 and 0.3 µl L-1 methyl jasmonate, respectively. Based on our findings, the expression pattern of the Laccase gene may be regarded as a marker in evaluating postharvest characteristics of cut roses.