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標題: | IbPep1激活IbLRR-RK1所調控之甘藷防禦反應 IbPep1-mediated Activation of IbLRR-RK1 Receptor Regulates Defense Responses in Sweet Potato |
作者: | 呂學翰 Hsueh-Han Lu |
指導教授: | 葉開溫 Kai-Wun Yeh |
共同指導教授: | Axel Mithöfer;鄭秋萍 Axel Mithöfer;Chiu-Ping Cheng |
關鍵字: | 損傷相關分子模式,甘藷,植物防禦,蟲害,胜肽配體,植物受體, DAMP,sweet potato,plant DTI,herbivore,peptide ligand,plant receptor, |
出版年 : | 2023 |
學位: | 博士 |
摘要: | 甘藷(Ipomoea batatas)是重要的塊根作物,卻時常受到各種蟲害的威脅,而甘藷塊根富含高量具有胰蛋白酶抑制活性之儲藏蛋白 SPORAMIN,為其重要抗蟲機制之一,且在甘藷葉片中 SPORAMIN 基因表現會被機械性損傷、昆蟲取食或防禦相關揮發物誘導而快速表現,進而藉由抑制昆蟲腸道之消化力以增強植物對昆蟲之抵抗能力。不過,儘管目前對於受傷誘導 SPORAMIN 表現的信號傳導途徑已有一些了解,但關於其受體如何辨識逆境訊號卻仍無相關報導。本研究發現一個在甘藷葉中能被受傷/蟲咬誘導而表現之受體激酶 IbLRR-RK1 (leucine-rich repeat receptor kinase1),此受體蛋白質富含亮胺酸重複(leucine-rich repeat),親源分析顯示其屬於相近於番茄SlPEPR1以及阿拉伯芥AtPEPR1/2之peptide-elicitor receptors (PEPRs) 受體蛋白質家族。功能性研究發現激活此 IbLRR-RK1 受體能誘導許多典型的植物受傷天然免疫 (Damage-Associated Molecular Pattern (DAMP)-triggered immunity,簡稱DTI) 反應,包括: 過氧化物大量累積以及植物賀爾蒙乙烯之生合成。此外,本研究進一步發現能激活 IbLRR-RK1 之胜肽配體 IbPep1 與其前體蛋白 IbPROPEP1;利用人工合成的IbPep1與其衍伸胜肽進行試驗證實甘藷 IbPep1/IbLRR-RK1 為新的配體/受體系統並近似於其他植物典型的Pep/PEPRs系統。更重要的是,IbPep1 可能與另一參與 DTI 之胜肽 IbHypSys 協力或並行地傳遞訊號,以調控並增強甘藷抵抗昆蟲的能力。此外本研究也發現 IbLRR-RK1 與 SlPEPR1 能交叉識別其各自之配體 IbPep1 與 SlPep6,第一次揭示了旋花科與茄科 Pep/PEPR 系統之間的家族相容性。綜上所述,本研究以分子生物的方式更深入的揭示了甘藷在面對傷害和食草動物攻擊時的綜合防禦機制。 Sweet potato (Ipomoea batatas) is an important crop with tuberous roots that is vulnerable to various insect pests. To defense off herbivores, the tuberous roots of sweet potato contain a storage protein called sporamin, which exhibits inherent trypsin inhibitory activity. Transcription of SPORAMIN in sweet potato leaves can be rapidly induced by herbivore attack, wounding, or defense-related volatiles, leading to enhanced resistance against insects by suppressing their digestion. The signaling transduction network regulating SPORAMIN expression in wounding response to stress has been partially elucidated; however, the perception of stress-related signals by receptors in sweet potato remains unknown. In this study, a wound/herbivory-inducible pattern recognition receptor (PRR), namely IbLRR-RK1 (leucine-rich repeat receptor kinase1), was identified. Phylogenetic analysis revealed that IbLRR-RK1 belongs to the peptide-elicitor receptors (PEPRs), and is related to the receptors AtPEPR1/2 in Arabidopsis and SlPEPR1 in tomato. Functional assays demonstrated the activation of IbLRR-RK1 triggered typical Damage-Associated Molecular Pattern (DAMP)-triggered immunity (DTI) defense responses such as the oxidative burst or the synthesis of the phytohormone ethylene. Furthermore, a precursor protein, namely IbPROPEP1, was discovered, and this protein contains a peptide ligand named IbPep1 that can activate IbLRR-RK1. Experiments utilizing synthetic IbPep1 and its derivatives provided evidence for a novel ligand/receptor pair in sweet potato that is related to canonical Pep/PEPRs in other plant species. IbPep1 serves as a distinct signaling peptide in sweet potato and may function in conjunction with, or in parallel to, the previously identified HypSys peptides to enhance resistance against insects. Interestingly, IbLRR-RK1 and SlPEPR1 exhibit cross-recognition of their respective ligands, IbPep1 and SlPep6, revealing inter-family compatibility of the Pep/PEPR systems within the Convolvulaceae and Solanaceae families for the first time. In summary, this research provides insights into the comprehensive defense mechanisms of sweet potato in the face of injury and herbivore attack, shedding light on the molecular processes involved in these responses. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/88608 |
DOI: | 10.6342/NTU202302113 |
全文授權: | 同意授權(全球公開) |
顯示於系所單位: | 植物科學研究所 |
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