Analysis Of Differential Expression And Function Of Genes Responsed To Polycyclic Aromatic Hydrocarbons (Phenanthrene) Stress In Arabidopsis Thaliana

Polycyclic aromatic hydrocarbons (PAHs) pollution is a serious global environmental problem. With the acceleration of the industrialized process, in particular the use of large quantities of fossil fuels. PAHs pollution has reached to a very serious level. Because it can cause cancer, mutations, and many other cells of human health problems, the PAHs issue has aroused great concern. Plants can absorpt PAHs from the atmosphere, soil, and play a role in remediating the environment. However, the response mechanisms of plants to PAHs stress at the molecular level were not systematically studied yet. In this study, fluorescence quantitative PCR technology had been applied to study the response of Arabidopsis thaliana to PAHs (phenanthrene) stress. On the basis of the differential proteomics studies to phenanthrene stress, we first showed Arabidopsis response at the difference in mRNA level to phenanthrene stress, The main results were as follows:At different time course under PAHs (phenanthrene) stress, 30 protein-coding genes' expression at the transcriptional level presented significant differences. Among them, 24 protein-coding genes upregulated significantly in the course of the phenanthrene-treated, 6 protein-coding genes were downregulated. Expression differences of signal-transduction and methylation encoding genes suggested that nucleoside diphosphate kinase (At4g11010) and guanine nucleotide-binding protein (G protein Atlg18080) might participate in the cell signal transduction and through cytosine methylation to control the related genes turn or off. The response at mRNA level reached its peak in Arabidopsis when exposed to phenanthrene for 24 h. The expression of ROS-associated encoding genes and plant defense-related genes reached peak under 24 h stress and defense-related encoding genes emerged the second peak under 48 h phenanthrene stress. The expression of photosynthesis, glyco-catabiosis and amino acid synthesis related genes showed significant peak under the stress of 24 h, but were inhibited in a certain extent with stress time increased.In addition, the loss and gain-of-function technology was used to study functions of differentialy expressed genes. T-DNA insertion mutants from SALK were used to study the changes of Arabidopsis mutant phenotype under phenanthrene stress. Results showed that only one mutant phenotype (SALK₀46009) (inactivated gene: AT1g48030), was significantly different with the wild-type in root length among nine mutants. At the same time, this study also constructed two over expression vectors (AT1G18080, AT3G16420) and transformed into Arabidopsis plants with Agrobacterium tumefaciens-mediated transformation to further study the function of these genes.