- 學位論文
青枯病菌Pss190效應蛋白PopP3影響植物防禦反應之研究
The effect of Ralstonia solanacearum Pss190 effector PopP3 on plant immunity
若您是本文的作者，可授權文章由華藝線上圖書館中協助推廣。
摘要
青枯病菌 (Ralstonia solanacearum, Rs) 所引發之青枯病為重要的土壤傳播性細菌性植物病害，其寄主範圍廣，常造成全球農作物經濟損失。隸屬於phylotype I的青枯病菌菌株在感染番茄上具有毒力差異性，然而目前關於青枯病菌毒力的分子機制瞭解仍非常有限。Pss190 菌株源自番茄且具有極高毒力，透過基因體分析顯示 Pss190 特有效應蛋白 Pseudomonas outer protein P3 (PopP3) 可能是高毒力的關鍵因子。本研究室先前發現原本不具有 PopP3 之中毒力菌株 Pss4 表現 popP3 後可以提升其毒力，且在番茄中過量表現 popP3 會抑制植物 pathogen/microbe associated molecular patterns (PAMP)-triggered immunity (PTI) 相關之癒傷葡聚醣累積，並降低番茄對軟腐病菌 Pectobacterium carotovorum subsp. carotovorum (Pcc) 之抗性，但對菸草之過敏反應無影響。本研究旨在進一步探討 PopP3 影響植物防禦反應之分子機制。實驗結果發現，PopP3 確實可被青枯病菌分泌至細胞外，在植物細胞內以點狀形式聚集於細胞核與細胞質中，但並非位於粒線體或過氧化體。番茄與菸草中過量表現 popP3 會抑制 PTI 相關之癒傷葡聚醣累積、過氧化氫累積及指標基因 PTI5 表現，進而降低植物對 Rs、Pcc 及細菌性細斑病菌 (Pseudomonas syringae pv. tomato DC3000, Pst) 等病原細菌之抗性，但未顯著影響對真菌灰黴病菌 Botrytis cinerea 之抗性。此外，表現 popP3 會降低番茄對可引發氧化逆境之除草劑 methyl viologen (MV or paraguat) 的抗性。為進一步探討 PopP3 抑制植物防禦反應之分子機制，亦嘗試找尋其植物交互作用蛋白質，雖多方嘗試卻因遭遇困難而未果。本研究所得之資訊與基礎應有助於未來對青枯病菌毒力、植物與青枯病菌交互作用及病害防治之深入研究。
並列摘要
Ralstonia solanacearum (Rs) causes a deadly bacteria wilt (BW) and thus serious economic losses on a wide range of crops worldwide. Rs phylotype I strains confer varied degrees of virulence/aggressiveness on tomato plants; however, genetic information on pathogen virulence-related factors is still very limited. Our previous studies reveal that a predicted YopJ-type effector protein Pseudomonas outer protein P3 (PopP3) is unique to the high-virulent strain Pss190. popP3 expression enhanced the virulence of the medium-virulent strain Pss4, reduced tomato pathogen associated molecular patterns (PAMP)-triggered immunity (PTI)-related callose deposition, and therefore reduced tomato resistance to Rs and Pectobacterium carotovorum subsp. carotovorum (Pcc). However, the expression of popP3 did not affect tobacco hypersensitive response (HR). This study aimed to further elucidate the mechanism underlying the PopP3’s effects on plant PTI. Results of secretion assay revealed that PopP3 is secreted out of the Rs cells. PopP3 displayed punctate nuclear and cytosolic, but not mitochondrial nor peroxisomal, localization when overexpressed in Nicotiana bethamiana (Nb). Overexpression of popP3 in tomato and Nb reduced PTI-related callose deposition, H2O2 accumulation, and PTI5 expression, and decreased plant resistance to Rs, Pcc and Pseudomonas syringae pv. tomato DC3000 (Pst). However, popP3 overexpression did not cause a significant effect on plant response to the pathogenic fungus Botrytis cinerea. Moreover, popP3 overexpression decreased tomato tolerance to oxidative stress caused by methyl viologen (MV or paraguat). Furthermore, extensive efforts spent on identifying the plant interactor of PopP3 failed. The information collected from this study would pave the way to further studies on Rs virulence mechanisms, Rs-plant interactions and disease control.
並列關鍵字
Ralstonia solanacearum ； effector ； PopP3 ； virulence ； PAMP-triggered immunity ； oxidative stress參考文獻
吳紅葳。2013。效應蛋白 PopP3 在青枯病菌毒力之功能研究與青枯病菌噬菌體裂解蛋白之分析。國立臺灣大學植物科學研究所碩士論文。
鞠泰翔。2014。效應蛋白 RSp0213 與 PopP3 在青枯病菌致病力之功能研究。國立台灣大學植物科學研究所碩士論文。
Angot, A., Peeters, N., Lechner, E., Vailleau, F., Baud, C., Gentzbittel, L., Sartorel, E., Genschik, P., Boucher, C., and Genin, S. (2006). Ralstonia solanacearum requires F-box-like domain-containing type III effectors to promote disease on several host plants. Proc. Natl. Acad. Sci. USA 103: 14620-14625.
Antony, G., Zhou, J., Huang, S., Li, T., Liu, B., White, F., and Yang, B. (2010). Rice xa13 recessive resistance to bacterial blight is defeated by induction of the disease susceptibility gene Os-11N3. Plant Cell 22: 3864-3876.
Arlat, M., Gough, C.L., Zischek, C., Barberis, P.A., Trigalet, A., and Boucher, C.A. (1992). Transcriptional organization and expression of the large hrp gene cluster of Pseudomonas solanacearum. Mol. Plant Microbe Interact. 5: 187-193.