甘藍根腫（瘤）病整合性防治技術之開發

Abstract

十字花科根腫（瘤）病，為全球性且相當古老的病害，對於溫帶地區國家、或氣溫較低的種植地區，常造成相當嚴重的經濟損失。十字花科根腫（瘤）病菌（Plasmodiophora brassicae Woronin），感染十字花科植物，造成寄主植物根部組織異常腫大形成根瘤，進而影響根部輸水功能，嚴重時造成植株萎凋黃化，甚至死亡。根腫（瘤）病菌為絕對寄生菌，其生活史中主要是以耐受不良環境的休眠孢子殘存於土壤或植物殘體中，並作為田間病害傳播感染的來源。目前十字花科根腫（瘤）病的防治方法，主要是透過輪作、土壤燻蒸、添加石灰等土壤添加物、施用藥劑，或是栽種抗病品種等進行，不過效果仍相當有限。因此，本研究以開發甘藍根腫（瘤）病整合性的防治技術為目標，嘗試透過不同面向的防治策略，期望達到降低病害之目的。首先，於實驗室建立根腫（瘤）病菌的活體染色技術及根腫（瘤）病菌的偵測系統，利用簡單且快速的方法，藉以評估根腫（瘤）病菌的侵染與防治成效。再者，藉由qPCR技術及定量標準曲線的建立，在每克土壤中含有10^3-10^8個休眠孢子的有效範圍內，已可定量田間土壤病原菌量。此外，藉由染色、分子檢測及接種試驗，確認田間雜草以及多種不同屬的作物，可被根腫（瘤）病菌感染並傳播病害。而以蘿蔔做為誘引植物，可有效降低甘藍的發病。最後，亦嘗試利用生物燻蒸資材，如尿素及菜子粕，進行土壤燻蒸，結果顯示可以減少土壤中病原菌的族群量，藉此達到預防或防治的目的。透過本研究之研究結果，期望未來能夠應用於十字花科根腫（瘤）病之整合性防治，有效進行田間病害之管理。

Clubroot disease is a worldwide important disease of cruciferous crops, which can be dated back to the 13th century in Europe. The disease, caused by a biotrophic pathogen Plasmodiophora brassicae Woronin, primarily occurs in temperate countries or growing areas with low temperature. The infection often leads to gall formation in plant roots and subsequently causes leaf yellowing and wilting symptoms due to the disturbance of water movement and severe infection results in the death of infected plants. In the life cycle, the resting spores of P. brassicae can survive in soil or plant tissues for many years and serve as primary inocula for the disease in the fields. The control measures for clubroot disease include crop rotation, soil fumigation, soil additives such as lime, pesticides and resistant cultivars. However, environmental issues and the effectiveness of current measures are still major concerns. In this study, we aimed to develop integrated control techniques for cabbage clubroot. To monitor the infection and evaluate the effectiveness of disease control, we first established the vital staining protocol and pathogen detection system. By using qPCR and establishment of the standard detection curve, we can determine pathogen population in soil in the effective range of 103-108 spores/g soil. By staining, PCR and inoculation, we found that some weed plants and non-cruciferous crops were or can be infected by P. brassicae and potentially serve as survival or transmission sources in the fields. Furthermore, we found some varieties of radish can serve as decoy plant and effectively reduced the disease incidence of cabbage clubroot. To develop effective biofumigation technique, we tested materials including urea and rapeseed meal. In combination of selective microbes, we found both materials have potentials to further use for disease management in the fields. Based on the results of this study, we hope to further develop integrated control measures for clubroot disease in the fields.