异源表达番茄LeMPK3基因提高烟草的抗低温胁迫能力

Ectopic Expression of Tomato LeMPK3 Improved Chilling Tolerance of Tobacco(Nicotiana tabacum)

促分裂原活化蛋白激酶(MAPK)信号系统在植物应对环境胁迫中发挥重要作用。为了探讨Le MPK3基因在低温胁迫中的功能,我们从番茄中分离了Le MPK3基因并将其转化到烟草中,获得了异源表达Le MPK3基因的转基因烟草。RT-PCR分析结果表明,番茄幼苗在低温和高温胁迫及外源物质——过氧化氢(H2O2)、茉莉酸甲酯(Me JA)和水杨酸(SA)处理下Le MPK3基因的表达量提高。在烟草中异源表达Le MPK3基因可以提高超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性,增加脯氨酸和可溶性糖的含量,增强逆境相关基因的表达。说明异源表达番茄Le MPK3基因提高烟草对低温的抗性。

Mitogen-activated protein kinase（MAPK） cascades are important intracellular signaling events that mediate signal transduction associated with the plant response to environmental stress. In order to investigate the function of Le MPK3 under chilling stress, Le MPK3 was isolated from tomato（Lycopersicon esculentum） and transgenic tobacco（Nicotiana tabacum） plants were obtained. The transcription of Le MPK3 in tomato leaves was up-regulated by low and high temperatures, and by the exogenous signaling molecules methyl jasmonate（Me JA）, salicylic acid（SA） and hydrogen peroxide（H2O2）. Transgenic tobacco overexpressing Le MPK3 accumulate d less reactive oxygen specie s（ROS）, more supero xide dismutase（SOD）, peroxidase（POD）, catalase（CAT）, ascorbate peroxidase（APX） activities, more proline and soluble sugar contents, and more stress-responsive genes expression, leading to enhancing low temperature stress tolerance compared to th e control plants.