MYC2, a basic helix–loop–helix transcription factor, is a master regulator in Jasmonic acid (JA) signaling pathway. However, the functions of SlMYC2 in methyl jasmonate (MeJA)-mediated fruit chilling tolerance are far from being clearly understood. Thus, in the present work, we constructed SlMYC2-silenced tomato fruit by virus-induced gene silencing (VIGS) and investigated the function of SlMYC2 in MeJA-induced tomato fruit chilling tolerance. The results showed that MeJA treatment markedly induced the SlMYC2 expression; increased proline content, lycopene content, and antioxidant enzyme activities, including superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase; inhibited the increase of electrical conductivity and malondialdehyde content; and effectively reduced the chilling injury (CI) incidence and CI index. However, these effects of MeJA treatment were partially counteracted in SlMYC2-silenced tomato fruit, and the CI incidence and CI index in (SlMYC2-silenced + MeJA)-treated fruit were higher than those in MeJA-treated fruit. Our results indicated that SlMYC2 might be involved in MeJA-induced chilling tolerance, possibly by ameliorating the antioxidant enzyme system of fruit and increasing proline and lycopene levels.

中文翻译：

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SlMYC2参与茉莉酸甲酯诱导的番茄果实耐冷性

MYC2是基本的螺旋-环-螺旋转录因子，是茉莉酸（JA）信号传导途径的主要调控因子。但是，SlMYC2在茉莉酸甲酯（MeJA）介导的水果耐寒性中的功能尚不清楚。因此，在本工作中，我们通过病毒诱导的基因沉默（VIGS）构建了SlMYC2沉默的番茄果实，并研究了SlMYC2在MeJA诱导的番茄果实耐寒性中的功能。结果表明，MeJA处理显着诱导了SlMYC2表达; 增加脯氨酸含量，番茄红素含量和抗氧化酶活性，包括超氧化物歧化酶，过氧化物酶，过氧化氢酶和抗坏血酸过氧化物酶；抑制了电导率和丙二醛含量的增加；并有效降低了冷害（CI）发生率和CI指数。然而，MeJA处理的这些效果在被SlMYC2沉默的番茄果实中被部分抵消，并且（SlMYC2沉默+ MeJA）处理的果实的CI发生率和CI指数高于MeJA处理的果实。我们的结果表明，SlMYC2可能与MeJA诱导的耐寒性有关，可能是通过改善水果的抗氧化酶系统并增加脯氨酸和番茄红素的水平来实现的。