Isolation And Phenotype Analysis Of A Sensitive Mutant Of Arabidopsis Thaliana

Cd is considered to be highly toxic, difficult to degrade and genetically toxic substance. In recent years, it has been reported that a large number of genes in plants are related to cadmium stress response. These genes mainly include ZIP family, HMA family and so on. Through studying those genes in response to cadmium stress, some self-protection mechanisms including chelation, sequestration and etc have been found. However, it is a complex process that how plants respond to cadmium stress, during which some relevant mechanisms are still not deeply understood.We optimized screening conditions for Arabidopsis cadmium sensitive mutant, and have founded some plants that are sensitive to cadmium stress in the T-DNA insertion Arabidopsis mutant library. After that, we chose the mutant with the most obvious phenotype and named it atcsr-2, which was used for the following experiment materials. According to Tail-PCR, we knew that the insertional locus of atcsr-2is in At2g36130(correspondingly called AtCSR). This gene encodes peptidyl-prolyl cis/trans isomerases that could reduce energy in the process of protein folding, thus helping protein fold exactly.In order to explore the influence of the AtCSR gene locus mutation on Arabidopsis responding to cadmium stress at the physiological level, we measured some important physiological indexes, such as root length, cadmium cumulant、chlorophyll content、MDA content、H2O2level、proline content、soluble sugar and soluble protein. Therefore, after contracting these indexes between wide type and mutant with cadmium stress, we found that cadmium caused more damage to atcsr-2. It accumulated higher level of Cd2+, MDA, H2O2, and suffered more free radical damage. After identifying (confirming) atcsr-2suffering more significant oxidativestress than Col-O, we compared antioxidase activity and the expression of genes that encode those enzymes as well as gene expressions related to cadmium transportation between Col-0and atcsr-2with or without cadmium stress, all of which is in order to learn more correlative oxidation mechanisms. The results showed that oxidativestress activities such as CAT, SOD, POD, APX were lower in atcsr-2than those in wide type, and the results of gene expression matched well with those of oxidativestress activities. The expression of Cd intracellular transporter activity IRT1was elevated, while the expression of MRP3was downregulated, which led to Cd accumulation and enhancement of toxicity. In addition, through prokaryotic expression of AtCSR, we studied E. coli growth with cadmium stress, and assayed SOD, CAT activity. The findings revealed that inducible E. coli was less restrained contrast to not inducible E. coli, and oxidativestress activities were higher in the former.In conclusion, we studied sensitive phenotype of atcsr-2from physiological and biochemical index as well as molecular level, thus laying the foundation for further research in cadmium sensitive mechanism of atcsr-2.