【摘要】 DNA甲基化是一种在DNA甲基转移酶催化条件下发生的重要共价修饰作用，DNMTs是植株中重要的DNA甲基转移酶。DNMT2甲基转移酶基因最早发现于拟南芥中，即AtDNMT2。文章通过在美国国家生物技术信息中心（National Center for Biotechnology Information, NCBI）数据库进行序列比对获得番茄中DNMT2基因序列，并命名为SlDNMT2。通过比较11个物种中DNMT2保守域、进化树分析以及DNMT2结构域分析，发现不同物种中DNMT2具有较高同源性；通过同源克隆获得番茄SlDNMT2基因cDNA全长序列；实时荧光定量聚合酶链式反应（real-time quantitative polymerase chain reaction, RT-qPCR）技术分析SlDNMT2基因在番茄植株中的组织特异性表达情况，结果显示SlDNMT2在不同组织中均有表达，尤其是在花和叶中SlDNMT2的表达量较高；构建SlDNMT2融合表达载体pART-27-35S::SlDNMT2-eGFP,利用农杆菌介导的烟草瞬时表达系统确定SlDNMT2蛋白定位于细胞核。此外，该文还探究不同非生物胁迫条件对转基因RNAi植株生长发育状态的影响，结果显示转基因RNAi植株对300μmol/L Zn²⁺胁迫条件更加敏感。该文为研究SlDNMT2基因在植物生长发育过程中的生物学功能及其作用的分子机制提供了科学依据，并为进一步研究植物应对非生物胁迫时SlDNMT2基因的功能作用奠定了一定的理论基础。更多还原

【Abstract】 DNA methylation is an important covalent modification that occurs in the condition of the catalysis of DNA methyltransferase. DNMTs are important DNA methyltransferases in plants. The DNMT2 methyltransferase was first discovered in Arabidopsis thaliana, and named AtDNMT2. In this paper, firstly, the sequence of the coding region of DNMT2 in tomato was obtained by sequence alignment using National Center for Biotechnology Information（NCBI）database of USA and named SlDNMT2. Secondly, through the comparison of the DNMT2 conserved domain, analysis of phylogenetic tree and DNMT2 structure domain in 11 different species of plants, it was illustrated that there was a high homology of DNMT2 in various 11 plants. The full-length cDNA sequence of the tomato SlDNMT2 gene was obtained by homologous cloning. Thirdly, the tissue specific expression level of SlDNMT2 was detected by real-time quantitative polymerase chain reaction（RT-qPCR）, and the results showed that SlDNMT2 was expressed in all test tissues, and the expression level was high in leaves and flowers. Meanwhile, S1 DNMT2 fusion protein expression vector（pART-27-35 S::SlDNMT2-eGFP） was constructed and infected in tobacco using Agrobacterium-mediated transient expression system, and the results indicated that the SlDNMT2 protein was localized in the nucleus. The effects of different abiotic stress conditions on the growth and development of transgenic RNAi plants were also investigated, and the results demonstrated that the transgenic RNAi plants were more sensitive in 300 μmol/L Zn²⁺ stress conditions compared with wild type. This paper provides a scientific basis for exploring the function and molecular mechanism of SlDNMT2 in plant growth and development stage, and lays a theoretical foundation for further exploring the functional role of SlDNMT2 in response to abiotic stress.更多还原