LAUSR

Abstract Phytohormone methyl jasmonate (MeJA) plays an important role in fruit ripening. This research aimed to investigate the regulation of MeJA in ethylene biosynthesis and signal transduction during postharvest tomatoes ripening. After mature green cherry tomatoes were infiltrated with MeJA (0.5 mM) or deionized water (control) respectively, fruit colour and firmness, ethylene production, the activities and expressions of ACS and ACO, as well as the expressions of major genes involved in ethylene signal transduction were periodically monitored. Results showed that a significant acceleration in ripening in MeJA-treated fruit was observed, along with the accelerated changes of ethylene production, the enhanced activities and expression levels of ACS and ACO. The expression levels of ETR3, ETR4, ETR6, ETR7, EIN2, EIL2, EIL3, EIL4 and ERF1 were up-regulated (from 1.26- to 6.50-fold) by MeJA during tomatoes ripening. The expression of CTR1, however, was down-regulated (from 0.23- to 0.54-fold). Moreover, the expression of EIL1 was positively regulated at the early ripening stage whereas negatively regulated at the late ripening stage (11.76-/0.39-fold), whereas the expressions of CTR3 and CTR4 showed the opposite expression patterns (0.15-/7.78-fold, 0.48-/2.00-fold). Results suggested the up-regulation of the genes associated with ethylene biosynthesis, as well as the up-regulated transcriptional levels of the most genes involved in ethylene signal transduction, leading to the increase of ethylene production, response and action, would be one of the major mechanisms of MeJA in accelerating postharvest tomatoes ripening.