Effects of methyl jasmonate on expression of genes involved in ethylene biosynthesis and signaling pathway during postharvest ripening of apple fruit

Ethylene plays a key regulatory role in the ripening of climacteric fruit. In addition to ethylene, jasmonates (JAs) have also been demonstrated to play a role in the regulation of the fruit ripening. Apple (Malus × domestica Borkh.) fruit is a common climacteric fruit. Research has been conducted to illustrate the effects of JAs on ethylene production in apple fruit, but little is known about the molecular mechanisms underlying the role of JAs in ethylene biosynthesis and signaling pathway during the ripening of apple fruit. To better understand the effects of JAs on the expression of key genes involved in the ethylene biosynthesis and signaling pathway during postharvest ripening of apple fruit, apples harvested at commercial maturity were treated with methyl jasmonate (MeJA). Our data indicated that MeJA treatment increased ethylene production during fruit ripening. The expression of MdACS1, MdACS6, MdETR1, MdCTR1-3, MdCTR1-4, MdCTR1-5, MdEIN2A, MdEIN2B, MdEIL4 and MdERF1 was positively regulated by MeJA treatment at the early ripening stage, whereas the expression of MdEIL3 was positively regulated by it at the late ripening stage. MeJA treatment enhanced the expression of MdACS3a, MdACS8, MdACO1, MdACO2, MdETR2, MdERS1, MdERS2 and MdEIL1 during the entire storage period, whereas it had no effect on the expression of MdCTR1-1, MdCTR1-2 and MdEIL2 during fruit ripening. The expression of MdERF2 and MdACS1 was negatively by MeJA treatment during the period when the ethylene peak existed. These results indicated that the expression of genes involved in the ethylene biosynthesis and signaling pathway was differentially regulated by JAs during postharvest ripening of apple fruit.