| Summary: | 碩士 === 國立成功大學 === 生命科學系碩博士班 === 98 === Arsenic (As) is considered as the most common toxic metalloid which is widely found in the environment. It primarily exists in the form of inorganic arsenate or arsenite. Under the circumstances of contaminated groundwater, As would penetrate into the food chain through irrigation of vegetables and crop plants and then threatens human health to cancer. However, what impact that As causes to the molecular response and gene expression of plants has not been extensively characterized currently, therefore this study aims to explore how plants respond the nature of toxicity and the mechanism of signal transductions when facing the abiotic stress. First, when Col-0 and Ws-2 seedlings were subjected to arsenate treatment for 2 days, the root elongation rate of Col-0 was found significantly higher than that of Ws-2. In addition, after the exogenous treatment of 100 μM arsenate for 3 hours, the result showed that arsenic accumulation in Ws-2 was 1.86 times higher in comparing with Col-0’s. Accordingly, Col-0 exhibited more tolerance to arsenate stress than Ws-2. Next, the ATH1 gene chip was used to compare the transcriptome of Col-0 and Ws-2. With the treatment of 100 μM arsenate for a short period of time (1.5hrs and 3 hrs), Aquaporin transporter family and LeOPT1-like transporter family genes showed more down-regulated gene numbers and were repressed with consistency. Besides, genes encoding glutathione transferase (GST) and ABC transporter were found to be significantly induced in Ws-2. Based on the definition of the tolerance-associated gene, 14 transcription factor genes could be sorted to 9 families : AP2/EREBP, bHLH, C2H2, C3H, MBF1, MYB-related, Trihelix, WRKY and ZIM. And Ethylene-related genes were found only regulated in Col-0. This might suggest that when Col-0 face the arsenate stress, Ethylene involved in the process. To sum up, this study presents a comprehensive survey of global transcriptional regulation under arsenate stress. The results described here will help to further our understanding of the underlying mechanisms of arsenate toxicity and tolerance in plants.
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