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  • 學位論文

阿拉伯芥凝集素受體激酶參與茉莉酸經由氣孔調控之免疫機制

Two Arabidopsis Lectin Receptor Kinases Involved in Jasmonic Acid Mediated Stomatal Immunity

指導教授 : 金洛仁

摘要


對於植物而言,關閉氣孔是第一道防禦植物葉部病原細菌入侵的防線,由於共演化的結果,有些病原細菌會釋出物質使關閉的氣孔打開,讓病原菌得以無限的侵入植物細胞。有些研究也指出病原菌引起的氣孔關閉需要兩種植物荷爾蒙水楊酸以及離層酸的參與,但是目前為止,對於另一種植物荷爾蒙茉莉酸,其參與在細菌誘發氣孔關閉的機制尚未被釐清。 先前實驗室的研究指出兩種阿拉伯芥凝集素受體激酶(LecRKV.5以及LecRKVI.2)分別都參與氣孔的調節,但由於阿拉伯芥凝集素受體激酶(LecRK)包含四十五種,因此,我們想了解是否其他LecRK也會參與在植物免疫反應的機制中,從微陣列基因表現資料庫中選取九個LecRK的基因,並且取得基因喪失功能的突變植株,其中另外兩種基因的突變株在感染細菌性斑點病病原菌Pseudomonas syringae以及細菌性軟腐病病原菌Pectobacterium carotovorum之後較為感病。 此外,也發現這兩種基因的突變株皆喪失細菌、病原菌特定分子標誌和甲基茉莉酸所誘發氣孔關閉的現象,但是處理水楊酸以及離層酸之後氣孔仍正常關閉。對於根長以及下游基因表現量測試,突變株和野生型相比,處理甲基茉莉酸後並沒有改變。進一步利用共軛焦顯微鏡觀察綠色螢光蛋白質標記,結果證明具有LecRK序列之重組綠色螢光蛋白質累積於細胞膜上。由以上結果,可以推論兩個新找到的LecRK對於細菌以及甲基茉莉酸所誘發的氣孔關閉,扮演一個正向調節的因子。

並列摘要


Bacterial entry into host tissue is a critical step for subsequent successful infection. In plants, stomata closure provides a physical barrier against foliar bacterial infection. Several pathogens have developed the ability to reopen closed stomata and enter into host tissue. Three plant hormones, salicylic acid (SA), methyl jasmonic acid (MeJA) and abscisic acid (ABA) are required in the stomatal response to bacteria. However, the link between stomatal closure and plant hormone still remains unclear. In a previous study, the lab discovered found two lectin receptor kinases, (LecRK) V.5 and VI.2, negatively and positively regulating stomatal immunity, respectively. Since LecRKs family consists of 45 members, we performed a reverse genetic screening to identify other candidate LecRKs involved in the stomatal response. Two T-DNA insertion mutant lines, lecrk-D and lecrk-F, were found to have more serious symptom upon infection by Pseudomonas syringae pv tomato strain DC3000 (Pst DC3000) and Pectobacterium carotovorum subsp. carotovorum SCC1 (Pcc SCC1) after surface-inoculation. We provide evidence that that LecRK-D and LecRK-F positively regulate MeJA-induced stomatal immunity.

並列關鍵字

LecRK Stomata MeJA

參考文獻


References
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