碩士 / 國立中央大學 / 生命科學系 / 101 / The greenhouse effect has lead to serious global warming, and high temperature is a major limiting factor to plant growth and development.We have used a forward genetics approach to screen for heat-intolerant mutants of Arabidposis after ethyl-methane sulfonate (EMS)-mutagensis. hit2 was therefore isolated on the basis of its impaired ability to withstand moderate heat stress (37℃). The hit2mutant harbored a nonsense mutation of ArabidopsisEXPORTIN1A (XPO1A) gene, which encodes a nuclear export receptor that mediates translocation of NES containing proteins across nuclear envelope.Treatments under different heat stress regimes and tests with ROS-detecting dyes further revealed that hit2 was defective in basal but not in acquired thermotolerance due to the inability to protect plant against heat-induced oxidative stress. Arabidopsis contains two copies of XPO1 homologs, HIT2/XPO1A and XPO1B. Nevertheless, xpo1b knockout mutant was not sensitive to heat and oxidative stresses. The transcript levels of HIT2 and XPO1B in wilt type were similar regardless whether the plants were heat stressed or not. However, the transcript level of XPO1B in hit2 was higher than that in wilt type. Yeast two hybrid experiment and BiFC assay were then conducted and revealed that HIT2/XPO1A had a stronger affinity forNES-conraining heat stress transcription factors (HSFs) These resultscollectively indicated that, despite a possible compensatory mechanism between XPO1A and XPO1B, thenuclear-cytoplasmic balance of Arabidopsis HSFs is specifically mediated by HIT2/XPO1A, which is potentially necessary for heat tolerance in plants.
| Identifer | oai:union.ndltd.org:TW/101NCU05105060 |
| Date | January 2013 |
| Creators | Kai-yu Chang, 張凱郁 |
| Contributors | Shaw-jye Wu, 吳少傑 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 75 |
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