利用转基因烟草确定AtELHYPRP2蛋白对赤霉菌的抗性及其亚细胞定位特征

Subcellular localization and resistance to Gibberella fujikuroi of AtELHYPRP2 in transgenic tobacco

摘要:

采用遗传转化技术获得了整合有拟南芥AtELHYPRP2 (EARLI1-LIKE HYBRID PROLINE-RICH PROTEIN 2, AT4G12500) 基因的转基因烟草株系，研究了该基因编码蛋白对真菌病原体赤霉菌的抗性及其亚细胞定位特征。以拟南芥Col-0生态型基因组DNA为模板，通过聚合酶链反应扩增AtELHYPRP2基因编码序列，经限制性酶切后连接至pCAMBIA1302载体，构建产生pCAMBIA1302-AtELHYPRP2-GFP融合表达载体。进一步采用农杆菌LBA4404转化烟草叶片外植体，筛选得到转基因烟草植株。RT-PCR、Western blotting印迹分析结果显示，AtELHYPRP2基因在转化体中可以有效表达。激光共聚焦显微观察发现AtELHYPRP2-GFP融合蛋白产生的绿色荧光与碘化丙啶染色后产生的红色荧光能够重合，说明AtELHYPRP2蛋白定位于细胞表面。真菌侵染实验结果显示，组成性表达AtELHYPRP2基因能够增强烟草对赤霉菌的抗性，被侵染部位有明显的H2O2积累。转基因烟草植株中PR1基因的本底表达水平比野生型高，PR1和PR5基因的系统表达水平比野生型高，说明AtELHYPRP2基因可能在SAR反应中具有一定的作用。

Abstract:

The subcellular localization and the resistance to fungal pathogen Gibberella fujikuroi of the protein encoded by Arabidopsis AtELHYPRP2 (EARLI1-LIKE HYBRID PROLINE-RICH PROTEIN 2, AT4G12500) were investigated using transgenic tobacco plants. The coding sequence of AtELHYPRP2 was amplified from genomic DNA of Col-0 ecotype. After restriction digestion, the PCR fragment was ligated into pCAMBIA1302 to produce a fusion expression vector, pCAMBIA1302-AtELHYPRP2-GFP. Then the recombinant plasmid was introduced into Agrobacterium tumefaciens strain LBA4404 and transgenic tobacco plants were regenerated and selected via leaf disc transformation method. RT-PCR and Western blotting analyses showed that AtELHYPRP2 expressed effectively in transgenic tobacco plants. Observation under laser confocal microscopy revealed that the green fluorescence of AtELHYPRP2-GFP fusion protein could overlap with the red fluorescence came from propidium iodide staining, indicating AtELHYPRP2 is localized to cell surface. Antimicrobial experiments exhibited that the constitutive expression of AtELHYPRP2 could enhance the resistance of tobacco to fungal pathogen G. fujikuroi and the infection sites could accumulate H2O2 obviously. The basal expression levels of PR1 and the systemic expression levels of PR1 and PR5 in transgenic tobacco plants were higher than that of the wild-type plants, suggesting AtELHYPRP2 may play a role in systemic acquired resistance.