瞬时过表达MnERF2基因对桑树耐盐性的影响

Effects of MnERF2 Gene on Salt Tolerance in Transient Overexpression Mulberry

为探明桑树AP2/ERF转录因子MnERF2基因对桑树耐盐胁迫能力的影响,利用构建好的植物过表达和抑制表达载体瞬时转化桑树,并比较分析NaCl胁迫前后瞬时转化桑树中的活性氧(ROS)含量、抗氧化酶活性、抗氧化物质含量以及抗氧化酶基因的表达量,以综合评定MnERF2基因的耐盐功能。通过荧光定量RT-PCR对盐胁迫后MnERF2表达量的分析显示,成功获得MnERF2基因瞬时过表达(OE)、抑制表达(RNAi)转基因植株。进一步的生理指标分析结果显示,不同时间盐胁迫下瞬时过表达MnERF2植株中的ROS(O_(2)^(-)·、H_(2)O_(2)、·OH)和丙二醛(MDA)含量明显低于对照和RNAi株系,过氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、谷胱甘肽S-转移酶(GST)活性以及抗坏血酸(AsA)、还原型谷胱甘肽(GSH)、脯氨酸含量高于对照和RNAi株系,且48h处理下SOD、POD、CAT三种酶基因表达量显著高于对照和RNAi株系。说明MnERF2基因响应桑树的盐胁迫,通过提高植株的保护酶活性和抗氧化物质含量、降低活性氧氧化及细胞损伤程度提高桑树的耐盐能力。

To investigate the effects of AP2/ERF transcription factor MnERF2 on salt resistance of mulberry, the plant overexpression vector and knockdown vector were constructed and transient transformed into mulberry. The ROS content, antioxidant enzymes activities, antioxidant substances contents and expression level of antioxidant enzyme genes in transient transformed mulberry were analyzed before and after NaCl stress, and the function of MnERF2 in salt tolerance was comprehensively evaluated. The analysis of MnERF2 expression after salt stress by fluorescence quantitative RT-PCR showed that the MnERF2 gene transiently overexpressed(OE) and inhibited(RNAi) transgenic plants had been successfully obtained. Further analysis of physiological indicators showed that the contents of O_(2)^(-)·、H_(2)O_(2)、·OH and MDA in OE plants under salt stress at different times were significantly lower than those in wild and RNAi plants, while the activities of SOD, POD, CAT and GST were higher as well as the contents of AsA, GSH and proline. The expression level of the three enzyme genes was significantly higher than those of wild and RNAi plants after 48 h treatment. It indicated that MnERF2 gene responded to the salt stress of mulberry, and the salt tolerance of mulberry could be improved by increasing the activity of protective enzymes and the content of osmotic regulatory substances, and reducing the degree of reactive oxygen oxidation and cell damage.