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標題: | 水稻轉錄因子OsbHLH046參與水稻幼苗鹽逆境之耐受性 The Rice Transcription Factor, OsbHLH046, Contributes to Salt Stress Tolerance at Seedling Stage |
作者: | Sung-Han Yu 游松翰 |
指導教授: | 張孟基(Men-Chi Chang) |
關鍵字: | bHLH,GUS,ICP-OES,qRT-PCR,鹽逆境,轉錄因子, bHLH (basic helix-loop-helix),GUS,ICP-OES,qRT-PCR,Transcrption factor,Salt stress, |
出版年 : | 2016 |
學位: | 碩士 |
摘要: | 水稻bHLH轉錄因子(basic helix-loop-helix transcription factor, bHLH TF)為重要之轉錄因子多基因家族,參與諸多生理功能,包括生長發育以及對抗非生物逆境等。由於轉錄因子多基因家族功能互補特性,如何確認特定轉錄因子之功能在研究上有一定之困難度。在本篇研究中,我們由實驗室先前水稻DNA微陣列的分析結果找出了在鹽及乾旱逆境下基因表現受抑制之轉錄因子OsbHLH046,並進一步以RT-PCR確認之。根據OsbHLH046-GFP之融合蛋白表現分析,發現OsbHLH046為一核蛋白。而Rice eFP browser與OsbHLH046 pro::GUS轉植株染色結果分析則顯示OsbHLH046在水稻胚、種子根、側根、幼苗時期地上部與花藥等部位皆有表現,其表現隨著幼苗葉齡漸大而有減弱之趨勢,但於成熟之花藥仍具高表現量。而OsbHLH046之Knock-down Tos17插入突變株相比於野生型植株有著較差的發芽率,較低的株高與較差的鹽逆境恢復性。丙二醛之含量測定亦顯示Osbhlh046突變株於鹽逆境下含量較野生型植株高。另外,qRT-PCR結果顯示部分鹽逆境耐受相關基因如OsNHX2與OsABI5在鹽逆境恢復階段中於Osbhlh046與野生型植株彼此間有著差異表現。而在ICP-OES元素分析的結果中,發現Osbhlh046植株在地下部於鹽逆境處理後復水五天,其K+/Na+比值較高,相較於野生型,無法維持Na+之恆定性而恢復性較差。最後,OsbHLH046過量表現系之癒傷組織相比於其他轉殖系,再生率差值達74%左右。綜上所述, OsbHLH046應參與種子發芽、植株生長,並且於鹽逆境下作為ㄧ正向調控因子參與水稻之耐受性。 Rice basic-Helix-Loop-Helix (OsbHLH) transcription factors (TFs) belong to a multiple gene family and are known to involve in rice growth, development, regulating abiotic stress-responsive gene expression and tolerance of rice. However, because functional redundancy within the super gene family and the pleiotropic effect of individual TF, the specific function for corresponding OsbHLH is not easy to be determined. In this study, we identified an OsbHLH046 TF which is down-regulated by salt and cold treatments from previous microarray result and further confirmed the gene expression by reverse transcription-PCR (RT-PCR). The OsbHLH046-GFP fusion protein showed OsbHLH046 is located in nucleus. Based on the predication of rice eFP browser and the GUS-histochemical staining indicated that OsbHLH046 is expressed in the embryo, seedling root, lateral roots, shoots and anthers. The gene expression was higher at the early germination stage then declined to lower level within 3rd leaf stage. Compared with WT, the Osbhlh046, a Tos17 knocked-down rice mutant, displayed late seed germination, growth retardation, and unable to recover from salt stress at seedling stage. The q-PCR data indicated that salt tolerance related genes in such as OsABI5, OsNHX2 were differential expressed between two plants during recovery stage. The MDA was overaccumulated in Osbhlh046 mutant compared to wild type after recover from salt stress. The ICP-OES elemental analysis also revealed that the Osbhlh046 plant have lower K+ content level, which may not able to maintain the Na+ homeostasis. Meanwhile, the callus of OsbHLH046 overexpression line showed a relative poor regeneration rate. Taken together, these results suggested that OsbHLH046 plays as a positive regulator in seed germination, seedling growth, and contributes to the ability of rice to recover from salt stress. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/50505 |
DOI: | 10.6342/NTU201601132 |
全文授權: | 有償授權 |
顯示於系所單位: | 農藝學系 |
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