Peach undergoes a rapid ripening and senescence, resulting in quality deterioration after harvest. Ethylene is essential for ripening and senescence in climacteric fruit. Although methyl jasmonate (MeJA) has been found to suppress ethylene biosynthesis, the underlying mechanism is unknown. We investigated the regulation of MeJA treatment (10 μM, 24 h) on the quality, ethylene biosynthesis and signaling, and jasmonic acid (JA) metabolism and signaling in ‘Xiahui 8’ peach stored at 20 °C. MeJA treatment maintained better fruit quality and reduced ethylene production (the reduction of peak value reached 24 %) during storage. The activities of 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxidase (ACO) decreased by 15–28 % and 15–19 % in MeJA treated fruit during storage. Additionally, the expressions of genes involved in ethylene signaling were downregulated in MeJA treated fruit. MeJA treatment enhanced JA biosynthesis through increasing the activities of allene oxide synthase (AOS), allene oxide cyclase (AOC) and JA-amino synthetase (JAR) during early storage. However, the JA-inducible catabolic pathways and self-repression of myelocytomatosis proteins2 (MYC2) were activated in MeJA treated fruit thereafter. This resulted in the decrease of transcription and JA-Ile accumulation, which reduced by at most 56 % and 73 % when compared with CK, respectively, on day 0 and day 5. These results suggested that negative feedback regulation terminated and repressed the JA signaling, therefore diminishing its enhancement effect on ethylene biosynthesis in peach during storage.

中文翻译：

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采后施用茉莉酸甲酯通过激活 JA 信号通路负反馈抑制桃子乙烯生物合成和信号传导

桃子经历快速成熟和衰老，导致收获后品质恶化。乙烯对于更年期水果的成熟和衰老至关重要。尽管已发现茉莉酸甲酯（MeJA）可抑制乙烯生物合成，但其潜在机制尚不清楚。我们研究了 MeJA 处理（10 μM，24 h）对 20 °C 保存的“夏惠 8 号”桃品质、乙烯生物合成和信号传导以及茉莉酸（JA）代谢和信号传导的调节作用。 MeJA处理保持了较好的果实品质，并降低了贮藏期间乙烯的产生（峰值降低达24%）。经过 MeJA 处理的果实在贮藏期间 1-氨基环丙烷-1-羧酸合酶 (ACS) 和 1-氨基环丙烷-1-羧酸氧化酶 (ACO) 的活性分别降低了 15-28% 和 15-19%。此外，在 MeJA 处理的水果中，参与乙烯信号传导的基因表达下调。 MeJA 处理通过增加早期储存期间丙二烯氧化物合酶 (AOS)、丙二烯氧化物环化酶 (AOC) 和 JA-氨基合成酶 (JAR) 的活性来增强 JA 生物合成。然而，JA 诱导的分解代谢途径和骨髓细胞增多症蛋白 2 (MYC2) 的自我抑制此后在 MeJA 处理的果实中被激活。这导致转录和 JA-Ile 积累的减少，与 CK 相比，在第 0 天和第 5 天分别减少最多 56% 和 73%。这些结果表明负反馈调节终止并抑制了 JA 信号传导，从而减弱了其在贮藏过程中对桃子乙烯生物合成的促进作用。