Pseudomonas putida A7及 Streptomyces coelicolor M145 誘發阿拉伯芥系統性抗病之研究

Studies on systemic resistance induced by Pseudomonas putida A7 and Streptomyces coelicolor in Arabidopsis thaliana

鄭涵丹(Han-Tan Cheng)

指導教授 ： 林乃君

國立臺灣大學/生物資源暨農學院/農業化學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201703331

摘要

農業上，為了增加作物產量及避免害蟲或病原菌造成的損失，通常會施用化學肥料及農藥。然而，施用這些化學物質所衍生的環境議題，讓人們開始擔心其對生態系會造成進一步的破壞，因此近年來有許多研究都希望找出替代方法來降低化學藥劑的使用。許多學者提出將具直接或間接促進植物生長之促進植物生長根棲細菌 (Plant growth-promoting rhizobacteria, PGPR ) 導入綜合蟲害管理 (integrated pest management)， 應是一個很好的策略。Pseudomonas putida A7及 Streptomyces coelicolor strain M145分別為由番茄根部分離到的內生菌及土壤中的微生物，均為可以促進植物生長根棲細菌，本研究中發現其不但可以促進阿拉伯芥地上部的生長，也可以提高抵抗病原菌 Pseudomonas syringae pv. tomato (Pst) DC3000 的能力。以 P. putida A7 進行根部處理後的植物，無法於 jar1、pad4 和npr1等突變植株上誘導抗性之現象均顯示 P. putida A7 產生之抗性反應與水楊酸、茉莉酸及乙烯的訊息傳導路徑有關。利用RT-PCR分析發現，水楊酸傳導路徑的指標基因 PR1 和 PR5在接種 Pst DC3000 後，其在葉部表現量較高且較快表現；而茉莉酸及乙烯傳導路徑的指標基因 LOX2、HEL及GST2 的表現也有類似現象。S. coelicolor M145 同樣能使阿拉伯芥野生株及突變株 pad4 產生對 Pst DC3000 抗性反應，卻無法於 jar1、sid2 和npr1等突變植株上誘導抗性之現象，均顯示其產生之植物系統性抗病反應與水楊酸、茉莉酸及乙烯的訊息傳導路徑有關。利用 RT-PCR 分析發現，S. coelicolor M145同樣可以較迅速誘導且提高 PR1 和 PR5 的表現，且在PDF1.2、LOX2、HEL 及 GST2 的表現上也有相同現象。透過實際萃取植物中水楊酸與茉莉酸的含量並以 high performance liquid chromatography 偵測後發現，經過P. putida A7 與 S. coelicolor M145接種後，受到Pst DC3000 感染之阿拉伯芥，其茉莉酸之含量均增加。綜言之，P. putida A7及S. coelicolor M145處理根系後，影響植物荷爾蒙水楊酸、茉莉酸及乙烯訊息傳導，使阿拉伯芥誘發系統性抗性，產生防禦反應抵抗葉部病原菌 Pst DC3000 所產生的病害。

關鍵字

促進植物生長根棲細菌 ； 阿拉伯芥 ； 誘導系統性抗性 ； 植物防禦荷爾蒙

並列摘要

During agricultural practice, chemical fertilizers and pesticides are often applied to enhance crop yield and prevent losses caused by pests and pathogens. However, environmental issues derived from utilization of such chemicals raise concerns about further damage to our ecosystem, and alternative means with similar effects should be developed to lessen the problem. Use of plant growth-promoting rhizobacteria (PGPR) with ability to promote plant growth directly or indirectly becomes a good strategy incorporated into the integrated pest management (IPM) program. In our studies, two soil habitants, Pseudomonas putida A7 and Streptomyces coelicolor strain M145, were proved to be plant growth promoting rhizobacteria, which not only promote plant growth but also induce resistance against Pseudomonas syringae pv. tomato (Pst) DC3000 in Arabidopsis thaliana. Further studies showed that P. putida A7 can induce resistance against Pst DC3000 in the Arabidopsis mutant lines, jar1, pad4 and npr1. By means of semiquantitative RT-PCR, we also found that higher amount and faster expression of the salicylic acid (SA) maker genes PR1 and PR5 were observed in P. putida A7-pretreated Arabidopsis compared to the water-treated control after Pst DC3000 infection. Stronger and faster responses upon Pst DC3000 infection in the A7-pretreated Arabidopsis were also found in the expression of genes involved in jasmonic acid (JA) and ethylene (ET) signaling pathways, such as LOX2, HEL and GST2. These data indicate that SA and JA/ET signaling pathways are involved in P. putida A7-induced systemic resistance to Pst DC3000 in A. thaliana. On the other hand, S. coelicolor M145-treated Arabidopsis mutant lines, jar1, npr1 and etr1, lost their ability to trigger systemic resistance to Pst DC3000. Futhermore, the expressions of PR1 and PR5 as well as PDF1.2, LOX2, HEL and GST2 were also stronger and faster after Pst DC3000 infection. Taking togather, we demonstrated P. putida A7 and S. coelicolor M145 probably can use different mechanisms to affect signaling pathways involving SA, JA and ET, to induce systemic resistance against Pst DC3000 in A. thaliana.

並列關鍵字

plant growth-promoting rhizobacteria ； Arabidopsis thaliana ； induced systemic resistance ； defence phytohormones

參考文獻

Abbasi MK, Sharif S, Kazmi M, Sultan T, Aslam M (2011) Isolation of plant growth promoting rhizobacteria from wheat rhizosphere and their effect on improving growth, yield and nutrient uptake of plants. Plant Biosyst 145:159-168.

AbuQamar S, Moustafa K, Tran LSP (2017) Mechanisms and strategies of plant defense against Botrytis cinerea. Crit Rev Biotechnol 37:262-274.

Achard P, Vriezen WH, Van Der Straeten D, Harberd NP (2003) Ethylene regulates arabidopsis development via the modulation of DELLA protein growth repressor function. Plant Cell 15:2816-2825.

Afek U, Aharoni N, Carmeli S. (1994). A possible involvement of gibberellic acid in celery resistance to pathogens during storage. Acta Hortic 381:583–87.

Amian AA, Papenbrock J, Jacobsen HJ, Hassan F (2011) Enhancing transgenic pea (Pisum sativum L.) resistance against fungal diseases through stacking of two antifungal genes (chitinase and glucanase). GM Crops 2:104-109.