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 negatively affect the longevity and quality of horticultural crops, which should be considered in marketing management, especially for cut flowers. Methyl jasmonate, well known as a signaling molecule in plant defense responses, could be effective in improving the vase life of horticultural crops. The expression of Laccae gene, acting downstream of the ethylene signal transduction, induced by exogenous ethylene treatment. The PIP2 gene is one of the major groups of plasma membrane proteins that are link to aquaporin channels. This study investigated 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 cut roses vase life at all the examined concentrations, although it was most effective at 0.2 µl/l. Analysis of antioxidant enzymes indicated that the catalase activity at 0.2 µl/l and peroxidase activity under 0.2 and 0.3 µl/l methyl jasmonate concentrations were the highest, although both enzymes showed a decreasing trend during the vase life period. Proline levels significantly increased at 0.2 and 0.3 μl/L methyl jasmonate concentrations. 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 was under 0.2 and 0.3 µl/l methyl jasmonate, respectively. Based on our findings, the expression pattern of Laccase gene could be consider as a marker in evaluating postharvest characteristics of cut rose.