應用液化澱粉芽孢桿菌防治落花生白絹病與冠腐病

Abstract

本研究從台北市文山區的茶園土壤中篩選出具拮抗植物病原菌潛力的液化澱粉芽孢桿菌 TG4 (Bacillus amyloliquefaciens, TG4)，於培養基試驗，顯著抑制落花生白絹病 (Sclerotium rolfsii) 與冠腐病 (Aspergillus niger) 的菌絲生長。落花生白絹病喜高溫多濕，常發生在雨季及灌溉排水不良時，造成植株萎凋、枯死及果莢腐爛，影響產量損失可高達 80%，其寄生範圍廣，休耕、輪作亦無顯著效果。落花生冠腐病能在土壤與作物殘體上存活，種子攜帶病原菌為主要感染源，造成幼苗猝倒、成株萎凋，目前未有適當防治藥劑。為測試液化澱粉芽孢桿菌 TG4 的防治能力，進行生物防治試驗，澆灌液化澱粉芽孢桿菌懸浮液於土壤中，再接種白絹病或冠腐病於落花生幼苗，液化澱粉芽孢桿菌 Ba-BPD1 (Bacillus amyloliquefaciens, Ba-BPD1) 與白絹病之推薦藥劑撲滅寧 (Procymidone) 作為對照組，並且利用變性梯度膠體電泳 (Denaturing gradient gel electrophoresis，DGGE)，比較不同處理之間土壤的細菌菌相變化。液化澱粉芽孢桿菌 TG4 可分泌纖維素分解酵素 (Cellulase) 與抗生物質伊枯草菌素A (Iturin A)、表面活性素 (Surfactin)，其細菌培養液與分泌物質皆可抑制落花生白絹病及冠腐病的菌絲生長，伊枯草菌素A 可能為拮抗原因之一。生物防治試驗結果顯示撲滅寧防治白絹病的效果最佳，其次為液化澱粉芽孢桿菌 Ba-BPD1；液化澱粉芽孢桿菌 TG4 防治冠腐病的效果最佳，顯著降低病害的嚴重程度。添加液化澱粉芽孢桿菌懸浮液於土壤中二週後，土壤中的細菌菌相沒有明顯變化，液化澱粉芽孢桿菌不影響土壤的細菌菌相。

In this study, B. amyloliquefaciens TG4 was isolated from soil of the tea garden in Taipei city, it obviously inhibited fungal growth of Sclerotium rolfsii and Aspergillus niger in the antagonistic test. S. rolfsii is a major disease of peanut and prefers to warm and moist environment. Rainy days and excessive irrigation often cause symptoms, injured plants wither and occur rotten pods. The maximum loss of quantity is up to 80%. Since pathogens have broad host range, fallowing and crop rotation could not control it effectively. A. niger is a minor disease of peanut. Pathogens could exist in soil, crop residues and seeds. Injured seedlings lodge. There is no recommended fungicide for this disease. In order to test potential for biological control of B. amyloliquefaciens TG4, pouring bacterial suspension into soil, and then inoculating pathogens to peanut seedlings. B. amyloliquefaciens Ba-BPD1 and fungicide Procymidone are the other treatment. DGGE is used to discuss bacterial diversity in soil. B. amyloliquefaciens TG4 could generate cellulase, iturin A and surfactin. Incubated broth and supernatant of B. amyloliquefaciens could inhibit fungal growth f Sclerotium rolfsii and Aspergillus niger in the antagonistic test, iturin A may be one of the disease resistance mechanism. In the biological control experiment, using Procymidone is the best way to inhibit Sclerotium rolfsii. Pouring B. amyloliquefaciens Ba-BPD1 is secondly recommended. Pouring B. amyloliquefaciens TG4 is the best way to inhibit Aspergillus niger. After pouring bacterial suspension into soil for two weeks, B. amyloliquefaciens TG4 and B. amyloliquefaciens Ba-BPD1 both do not effect bacterial flora in soil.