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標題: | 轉錄因子OsbHLH068可促進植物鹽逆境耐受性 Rice transcription factor, OsbHLH068, confers salinity stress tolerance |
作者: | Pei-Chun Liao 廖珮君 |
指導教授: | 張孟基(Men-Chi Chang) |
關鍵字: | bHLH轉錄因子,非生物逆境,鹽逆境,鹽耐受性, bHLH transcription factor,abiotic stress,salt stress,salt stress tolerance, |
出版年 : | 2014 |
學位: | 碩士 |
摘要: | bHLH 轉錄因子調節植物生長發育及生理反應。水稻之 bHLH 轉錄因子基因家族共有173個成員,然而此些轉錄因子於逆境下之調控角色仍未明瞭。本研究旨在探討水稻 OsbHLH068 轉錄因子於植物逆境下之調控角色。首先利用水稻經非生物逆境處理所得之微矩陣晶片( microarray ) 數據挑選出非生物逆境誘導的 OsbHLH 基因,其中OsbHLH068 為受鹽高度誘導之轉錄因子,且相對應之阿拉伯芥同源基因為 AtbHLH112。經 RT-PCR 及 GUS 分析 OsbHLH068::GUS 及AtbHLH112::GUS 轉殖株並確認此兩基因皆受鹽逆境誘導且表現於管束組織之側根及根原基。而相較於阿拉伯芥野生型 (Col-0),atbhlh112 突變株較不耐逆境且葉片溫度較低。OsbHLH068 異源互補 ( heterologous expression ) 突變株AtbHLH112P::OsbHLH068-GFP 可功能性互補 atbhlh112 不耐鹽逆境的生理缺陷。35S::OsbHLH068 及 AtbHLH112P::OsbHLH068-GFP 轉植株具有發芽後期生育延遲 ( Post-germination developmental arrest, PGDA ) 之外表型,其在逆境下胚根突破種皮後子葉不完全展開。分析 OsbHLH068 蛋白質之次細胞定位與組織表現位置,發現融合蛋白 OsbHLH068-GFP 及 GFP-OsbHLH068 皆表現於細胞核內,並且表現於地上部及地下部之管束組織中。最後,相較於水稻野生型台農67號,35S::OsbHLH068 之轉殖水稻幼苗在 250 mM 高鹽處理下能於其第一葉之葉鞘分泌出較多的鹽類結晶。綜合以上結果顯示 OsbHLH068 為水稻鹽逆境耐受性之正向調控轉錄因子。 The basic/helix-loop-helix (bHLH) transcription factors (TFs) play important roles in the regulation of diverse developmental and physiological processes in plants. So far, at least 173 OsbHLH genes have been identified in rice. Though the expression levels of several OsbHLH genes were noticed to be up-regulated by salt treatments, such as OsbHLH068 gene; however, the gene functions of OsbHLH068 in salt-stress tolerance of rice are still unknown. In this study, the roles of OsbHLH068 and its Arabidopsis ortholog, AtbHLH112, were investigated under salt stress with reverse-genetics approaches. In Arabidopsis, under salt-treatment, the atbhlh112 mutant displays salt-intolerance and low leaf-temperature phenotypes. These physiological defects in atbhlh112 mutant could be complemented by heterologous expression of OsbHLH068 gene. In addition, heterologous over-expression of OsbHLH068 gene in Arabidopsis causes a post-germination developmental arrest (PGDA) phenotype, which refers to non-fully expanded cotyledon under salt treatment. Histochemical staining of promoter::GUS assay in transgenic Arabidopsis indicated that AtbHLH112 expressed in vascular tissue and trichome. Both OsbHLH068-GFP and GFP-OsbHLH068 fusion proteins are localized in the nucleus. Interestingly, compared with wide type (WT, Tainung67), the phenotypic analysis of over-expressed OsbHLH068 transgenic rice seedling showed increased salt crystals accumulation at the base of 1st leaf sheath under 250 mM NaCl treatment. Taken together, these results suggest that OsbHLH068 is a positive regulator that is involved in stress response of plant salt-stress tolerance. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/56320 |
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顯示於系所單位: | 農藝學系 |
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