請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/86228
標題: | 圓葉菸草內質網之 C-type lectin receptor like kinase NbCLRK參與植物對β-葡聚醣及疫病菌的免疫反應 The ER-localized C-type lectin receptor like kinase NbCLRK is involved in plant immune response toward β-glucans and Phytophthora parasitica |
作者: | 陳宜豐 Yi-Feng Chen |
指導教授: | 劉瑞芬 Ruey-Fen Liou |
關鍵字: | 內質網,疫病菌,植物免疫反應,C類凝集素,β-葡聚醣, β-glucan,endoplasmic reticulum,Phytophthora parasitica,plant immunity,C-type lectin, |
出版年 : | 2022 |
學位: | 碩士 |
摘要: | 真菌及卵菌細胞壁由許多種類的多醣堆疊構成,其中β-1,3;1,6-葡聚醣含量最多,而且許多類別的β-1,3;1,6-葡聚醣可作為microbe-associated molecular patterns (MAMPs) 引起植物基礎免疫反應 (pattern-triggered immunity; PTI)。目前關於醣類MAMPs所引起PTI之訊息傳遞路徑的瞭解主要奠基於真菌幾丁質的研究,至於β-葡聚醣如何引起免疫反應則尚未明瞭。本研究發現以昆布多醣(其以β-1,3;1,6-葡聚醣為主成分)處理圓葉菸草時,引起活性氧分子(reactive oxygen species; ROS)生合成、癒傷葡聚醣沿著葉脈累積,並導致原生質絲關閉。為探討相關調控機制,本研究自圓葉菸草選殖Dectin-1 (哺乳類動物負責辨識β-1,3-葡聚醣的受體) 之同源性基因,定名為NbCLRK,其編碼C-type lectin receptor like kinase (NbCLRK),而且不同種類植物僅含有單一或少數NbCLRK同源基因。在圓葉菸草被疫病菌感染的早期,NbCLRK的表現明顯下調。以Tobacco rattle virus (TRV) 介導NbCLRK基因靜默顯著增強昆布多醣在圓葉菸草引發的活性氧生合成量,顯示NbCLRK扮演負調控的角色。疫病菌接種試驗顯示,短暫過表現NbCLRK-GFP降低圓葉菸草的抗病性,基因靜默NbCLRK則導致較高的抗病性。有趣的是,將NbCLRK-GFP與內質網標誌蛋白mCherry-KDEL共表現時,NbCLRK-GFP的螢光訊號主要位於內質網,且呈現點狀分布;進一步分析發現NbCLRK-GFP的點狀分布與VAP27-1-mCherry所標記的內質網-細胞膜接觸點 (endoplasmic reticulum-plasma membrane contact sites; EPCSs) 部分疊合。綜合上述結果,本研究發現分布於內質網的NbCLRK可負面調控植物對抗疫病菌以及β-葡聚醣誘發的免疫反應,並揭示其作用可能涉及EPCSs,然而NbCLRK究竟如何藉由EPCSs影響植物免疫反應尚待更多探討。 The cell walls of fungi and oomycetes contain abundant polysaccharides with different compositions and structures. Among them, β-1,3;1,6-glucans are particularly enriched and many of them have been identified as microbe-associated molecular patterns (MAMPs) that elicit pattern-triggered immunity (PTI) in plants. Even though the defense signaling induced by fungal chitin has been well elucidated, our knowledge about β-glucan-induced immunity is very limiting. This study demonstrates that treatment of Nicotiana benthamiana with laminarin, which consists of β-1,3-glucan backbones with β-1,6-branches, triggered reactive oxygen species (ROS) production, callose deposition along leaf veins, and the closure of plasmodesmata. To investigate the mechanism, a gene homologous to Dectin-1, known as β-glucan receptor in mammals, was cloned from N. benthamiana, herein named NbCLRK, which encodes C-type lectin receptor like kinase. Phylogenetic analysis revealed NbCLRK and its homologs are singletons conserved in all plant species analyzed in this study. Tobacco rattle virus (TRV)-mediated gene silencing of NbCLRK enhanced ROS production triggered by laminarin, which suggests a negative role of NbCLRK in the regulation of plant defense response. When N. benthamiana was challenged with the oomycete pathogen Phytophthora parasitica, NbCLRK was downregulated in the early infection stage. Moreover, overexpression of NbCLRK downregulated, whereas gene knock-down enhanced plant resistance against P. parasitica. Of note, when transiently overexpressed by agroinfiltration, NbCLRK-GFP was found primarily on the punctate structures of cell periphery, which colocalized with the endoplasmic reticulum (ER) marker mCherry-KDEL. When coexpressed with the ER-plasma membrane (PM) contact site (EPCS) marker VAMP-associated protein (VAP) 27-1-mCherry, NbCLRK-GFP showed a distribution pattern partially overlapping with that of VAP27-1-mCherry. In summary, this study indicates that ER-localized NbCLRK negatively regulates not only plant response toward β-glucan but also immunity against P. parasitica, likely through the function of EPCS. More studies are needed to know how NbCLRK takes part in the regulation of PTI responses via the possible involvement of EPCS. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/86228 |
DOI: | 10.6342/NTU202202988 |
全文授權: | 同意授權(全球公開) |
電子全文公開日期: | 2027-08-31 |
顯示於系所單位: | 植物病理與微生物學系 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-110-2.pdf 此日期後於網路公開 2027-08-31 | 2.62 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。