Cloning and characterization of an Arabidopsis thaliana arsenic reductase gene (ACR2)

Arsenic is a toxic metalloid existing everywhere in the nature. It is toxic to most organisms and considered as human carcinogen. Arsenic contamination leads to severe health problems with diseases like damage of skin, lung, bladder, liver and kidney as well as central nervous system. It is very likely that too much chemicals such as cadmium and arsenic in the consumed foods can also lead to increased birth defects like spinal bifida. In some regions of South-East Asia, like Bangladesh, Burma, Thailand and India, arsenic contamination of human population via either food chain or drinking water is now considered as a national threat for mankind. As arsenic can be found everywhere in nature it may come in contact with food chain very easily through either water or cultivated crops. In South-East Asia the major cultivated crop is rice and it is the staple food for people in many countries like Bangladesh, Burma and Thailand. Cultivation of rice plants requires water either from rainfall or irrigation. Irrigated water in some regions of South-East Asia is highly contaminated with arsenic and by this way arsenic is accumulated in the rice corn which consumed not only by human but also by animals, birds and fishes. In order to avoid arsenic contamination in human food it is essential to find out a way to inhibit arsenic uptake in cultivated plants. Alternatively, we can also find out a way to metabolize arsenic "in plant". In my experiment I have used Arabidopsis thaliana as a model plant to isolate an arsenic reductase (ACR2) gene. This gene has been reported to be involved in metabolism, transport and sequestration of arsenic in plants. My thesis works include studies of the ACR2 gene based on characterization of the corresponding SALK mutants. All plants were exposed to arsenics under in vitro conditions. It was observed that the SALK mutants were more sensitive to arsenics in comparison with the wild type control plants. ACR2 gene was cloned from the genomic DNA of A. thaliana by using Phire Plant Direct PCR kits using database sequences as primers. The amplified product was first ligated to the vector pKOH152 and then transferred to E. coli DH5α competent cells. Recombinant bacterial colonies were screened by colony PCR to confirm the insertion of ACR2. The band (1.3 kb) obtained in gel image indicates that the ACR2 gene was cloned successfully. For further confirmation of these results the cloned gene should be sequenced