開發番茄青枯病和晚疫病之生物防治技術

番茄為臺灣重要蔬果，具有高經濟價值。臺灣氣候及環境適宜，全臺皆可種植番茄，主要產區為中南部。雖然種植不難，但番茄容易罹患許多病害，包括病毒病、青枯病及晚疫病等，常造成農民嚴重經濟損失，因此防治這些病害成為番茄種植的重要課題。在現今環保意識抬頭的情況下，生物防治無疑提供一個良好的選項。本實驗室先前從疫病菌抑菌土所分離的地衣芽孢桿菌 Bacillus licheniformis (31-1) 對於青椒疫病有顯著抑制效果，且可促進植株生長。本研究發現 B. licheniformis (31-1) 外泌至培養基的拮抗物質可抑制多種病原菌生長，包括腐霉病菌、疫病菌、番茄萎凋病菌及炭疽病菌等；此外，B. licheniformis (31-1) 產生之揮發性物質也能抑制前述部分病原菌的生長。為進一步鑑別 B. licheniformis (31-1) 外泌拮抗物質的成分，將 B. licheniformis (31-1) 大量培養後，進行拮抗物質萃取、HPLC 及 FIA-MS 分析，再經由比對 AntiMarin 資料庫發現其中兩個化合物為 ochrindoles D 和 streptovirudin-A1。在盆栽防治實驗中，澆灌處理 B. licheniformis (31-1) 可降低青枯病的罹病嚴重度，但無論是噴灑或是澆灌處理 B. licheniformis (31-1) 都無法抑制番茄晚疫病的發生，澆灌處理也無法促進番茄植株生長。此外，為獲得更多生物防治菌，本研究採集土壤樣本，以蔬菜汁培養並分離其中具潛力之微生物。目前以盆栽接種試驗篩選出一株具有防治青枯病潛力的細菌 (6-2)，經由16S rDNA 序列親緣關係分析，發現此菌可能為 Sinomonas 屬的成員。

關鍵字

地衣芽孢桿菌；拮抗物質；生物防治；青枯病菌；晚疫病菌；土壤微生物篩選

並列摘要

Tomato (Solanum lycopersicum L.) is an important economic crop in Taiwan, with the main cultivation areas encompassing the middle and southern Taiwan. It is susceptible to various diseases, including virus diseases, bacterial wilt, late blight, which cause heavy economic loss for the farmers. Consequently, management of tomato diseases is always an important issue, which usually involves the application of chemical pesticides. However, pesticide overuse is a direct threat not only to the environmental quality but also to food safety. As a result, biocontrol has become a better choice for crop cultivation in a ecofriendly and safe way. Previously, Bacillus licheniformis (31-1) was found to inhibit the growth of various pathogens including Phytophthora capsici, is effective for the control of Phytophthora blight on bell pepper, and is able to accelerate the growth of this plant. In this study, it is demonstrated that metabolites secreted by B. licheniformis (31-1) can inhibit the growth of various pathogens, including Pythium spp., Phytophthora spp., Fusarium spp. and Colletotrichum boninense. Volatile organic compounds produced by B. licheniformis (31-1) can also inhibit the growth of some of the aforementioned pathogens. Analyses based on butanol extraction, HPLC, and FIA-MS identified two of the substances secreted by B. licheniformis (31-1), namely ochrindoles D and streptovirudin-A1, respectively. When applied by soil drench on tomato plants grown in pots, B. licheniformis (31-1) reduced the disease severity of bacterial wilt. However, no matter applied by soil drench or by phyllosphere spray, B. licheniformis (31-1) failed to reduce the disease incidence of late blight. Application by soil drench failed to promote the growth of tomato. As well, to get more isolates for efficient biocontrol of tomato bacterial wilt, some bacterial and fungal isolates were collected from soil samples and screened for biocontrol potential. Among them, one bacterial isolate (6-2) showed good ability to reduce the disease severity of bacterial wilt. It is likely Sinomonas sp. as suggested by phylogenetic analysis of 16S rDNA sequence.