促進植物生長之根棲細菌Streptomyces sp. RS70誘導番茄對青枯病之系統性抗性

Induction of Systemic Resistance in Tomato to Bacterial Wilt by a Plant growth-promoting Rhizobacterium Streptomyces sp. RS70

鄧雅靜(Y. C. Teng) ； 曾國欽(K. C. Tzeng) ； 徐世典(S. T. Hsu)

《植物病理學會刊》 15卷2期 (2006/06) Pp. 107-116

https://doi.org/10.6649/PPB.200606_15(2).0005

摘要

Streptomyces sp. RS70為一可促進番茄生長之根棲細菌，且以種子被覆或幼苗澆灌處理具有防治番茄青枯病之效果，但在培養基上無抑制青枯病菌之能力。為瞭解RS70之防病機制，本研究探討其誘導系統性抗病之可能性。將RS70以注入法處理番茄頂葉後，於第七天再由根部澆權接種青枯病菌PS152時，青枯病之發病指數顯著低於頂葉未經RS70處理之對照組，此結果表示RS70可能誘導植株之抗性而降低發病程度。番茄頂葉經RS70注入處理後，至少需要六天才能有效誘導對青枯病之抗性，但此抗性僅持續數天。北方雜合分析發現，RS70之處理可誘發未處理葉片之致病過程相關蛋白基因PR-1之表現，在測試10天期間內，其mRNA表現量隨處理天數之增加而增多，至第八天達最高峰（較處理後0時增加約2.3倍），隨後則略為降低。Rs70不論以注入處理於頂葉或澆灌處理於根部後，皆能在未處理之葉片內偵測到PR-1mRNA之累積，顯示其誘發PR-1基因表現可向上或向下移行。本研究另以青枯病菌PS152之一株無致病力突變株測定時，發現其亦可誘導抗性並誘發PR-1基因之表現。

關鍵字

根棲細菌 ； 誘導抗病性 ； 青枯病 ； 番茄 ； PR-1蛋白基因

並列摘要

Streptomyces sp. RS70 is a rhizobacterium capable of promoting tomato growth and reducing bacterial wilt disease caused by Ralstonia solanacearum following either seed coating or seedling drenching. However, it has no inhibitory activity against R. solanacearum in vitro. To understand the mechanism by which Streptomyces sp. RS70 controls the bacterial wilt, we investigated whether RS70 could induce systemic resistance in tomato. The severity of bacterial wilt was significantly reduced when the top leaves of tomato seedlings were syringe-infiltrated with Streptomyces sp. RS70 and challenge-inoculated by root drenching with strain PS152 of R. solanacearum 7 days post infiltration, indicating that R570 may have induced systemic disease resistance. At least six days after leaf infiltration with RS70 were required for effective resistance to be induced. However, the induced resistance persisted only for several days. The Northern blot analysis revealed that RS70 treatment could induce PR-1 gene expression in noninoculated leaves, and in a 10-day test period, the quantity of PR-1 mRNA increased with time, reaching the highest at the 8th day and then slightly decreased. Accumulation of PR-1 mRNA in noninoculated leaves was observed not only by leaf infiltration but also by root treatment with RS70, indicating that the signal for PR-1 gene expression induced by RS70 may be transported downward and upward from the inoculated site. Similar to RS70, one of the four tested avirulent mutants of R. solanacearum PS152, was able to induce systemic resistance and increase PR-1 gene expression.

並列關鍵字

rhizobacteria ； induced resistance ； bacteria wilt disease ； tomato ； PR-1 gene