Effects Of MeJA On Quality And Expression Of Key Genes Involved In Ethylene Biosynthesis And Signal Transduction 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.The main results were as follows:1.Apples harvested at commercial maturity were treated with methyl jasmonate?MeJA?,and the effects of MeJA treatment on postharvest physiology and related quality of apple fruit were measured during postharvest storage at room temperature.The expression of key genes in ethylene biosynthesis and signal transduction pathway during postharvest fruit ripening by MeJA treatment was detected by qPCR.Our data indicated that MeJA treatment accelerates fruit softening during ripening of apple fruit,increased ethylene production and respiration rate in fruits,promoted the content of titratable acid?TA?,total soluble solids?TSS?,vitamin C?ASA?and starch content,increased malondialdehyde?MDA?and superoxide anion production rate?O₂^-·?.2.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 MeJA treatment can regulate the expression of genes involved in the ethylene biosynthesis and signaling pathway during postharvest apple fruit ripening.