化學藥劑與生物防治菌共同使用於防治馬鈴薯瘡痂病之評估

Abstract

馬鈴薯瘡痂病主要由馬鈴薯瘡痂病菌（Streptomyces scabies）造成，侵染馬鈴薯表皮組織形成凸起或凹陷之木質化壞疽病斑，破壞馬鈴薯之外觀，影響其經濟價值，是田間重要病害，台灣目前尚未有推薦之化學藥劑或微生物製劑防治此病害。由於生物防治菌於田間之防治效率易受到環境之影響，故本研究欲結合化學藥劑與生物製劑共同防治馬鈴薯瘡痂病，期許能提升個別防治的效率，並探討藥劑對液化澱粉芽孢桿菌Bacillus amyloliquefaciens Ba01重要基因表現之影響。研究首先以濾紙片擴散試驗與搖瓶培養發現Ba01對於免得爛和四氯異苯腈的耐受性較S. scabies PS07高，推測可能與Ba01產生內生孢子的特性有關。利用濾紙片擴散及馬鈴薯薯片試驗，發現免得爛250 ppm、125 ppm或四氯異苯腈200 ppm、100 ppm與Ba01具有共同或交替施用之潛力；且於PS07接種1天前、後施用處理，均有好的抑制效果。而兩化學藥劑並不影響Ba01重要二次代謝物表面素（surfactin）基因srfAD以及部分參與氮代謝相關基因（tnrA、glnR、codY）的表現。未來期望能進行盆栽及田間試驗，希冀提供農民防治馬鈴薯瘡痂病之參考。 Potato common scab mainly caused by Streptomyces scabies leads to the symptoms of raised and pitted corky lesions on the surface of potato tubers, damaging the potato appearance and affects the economic value of potatoes. Since it is an important disease in the field, there have been no recommended chemicals or biocontrol agents to manage the disease. Because of the unstable control efficiency of biocontrol agents in the field, the main purpose of this research is to combine chemicals with the biocontrol agent B. amyloliquefaciens Ba01 (Ba01) to control potato common scab and improve control efficacy. Meanwhile, the chemical's influence of important gene expression in Ba01 is investigated. The disk diffusion test and shake flask assay were used at first, and the results revealed that Ba01 was more tolerant to metiram and chlorothalonil than S. scabies PS07 (PS07) which might be due to the presence of endospores in Ba01. By adopting the disk diffusion and potato tuber slice assay, metiram 250, 125 ppm or chlorothalonil 200, 100 ppm possessed the potential efficacy in combination with Ba01 which were conducted 1 day before or after PS07 inoculation and retained better inhibitory effects on S. scabies PS07. Neither metiram nor chlorothalonil significantly affected the expression of surfactin producing gene srfAD and genes involved in nitrogen metabolism (tnrA、glnR、codY) in Ba01. We anticipate completing pot assay and field trial in the future and providing farmers an appropriate combination method in managing potato common scab.