| Summary: | 碩士 === 國立臺灣大學 === 植物科學研究所 === 107 === Heat shock response (HSR) is a universal mechanism in all organisms to overcome heat stress (HS) or higher than normal temperatures. While HSR was happening, the accumulation of heat shock proteins (HSPs) would protect cells from HS and this mechanism is controlled by heat shock factors (HSFs). The Arabidopsis HSF family contains 21 members; about half are involved in the signaling cascade of HSR. Some Arabidopsis HSFs are well-studied, for example, the class A HSF are considered to amplify or sustain the expression of HSPs because of containing activation domain; the class B lacks a typical activation domain, are considered to attenuated HSR. There has only one HSF in class C in Arabidopsis. Although HSFCs have been found to be involved in salt and drought stress in other plants, the function of HSFC1 in Arabidopsis has remained unknown. In our previous study, we found that HSFC1 could be induced by salt and ABA and the expression of HSFC1 was altered in ABA-deficient and ABA-insensitive mutants, indicated that ABA signaling is required for proper HSFC1 expression. In this study, T-DNA-insertional mutant and HSFC1-overexpression (OE), -VP16, and -SRDX plants were used for a functional study of the HSFC1 in response temperature stress and during various developmental stages. My study showed that the expression of HSFC1 was induced by cold stress not by heat stress. At the same time, I found that HSFC1-OE and HSFC1-VP16 plants were more heat tolerant phenotype under acquired thermotolerance assay. In seed germination test, I concluded that HSFC1-OE shows higher sensitive to salt, ABA and mannitol compared with the HSFC1-VP16 and HSFC1-SRDX seedlings. In root length assay, I concluded that HSFC1-OE also shows more sensitive to salt, ABA and mannitol compared with the HSFC1-VP16 and HSFC1-SRDX seedlings. Finally, in protoplast transactivation assay, I found that the ectopic expressed HSFC1 had negative effect on HSFA2, HSFA3 and HSFA6b in stress-responsible maker gene HSP18.2 induction. My research concluded that HSFC1 was induced by cold, salt and drought stress via ABA signaling pathway. We will research more regulation mechanisms about HSFC1 in the future.
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