應用枯草桿菌防治馬鈴薯瘡痂病

Application of Bacillus Subtilis on Controlling Potato Scab Disease Caused by Streptomyces scabies

林文平(Wen-Peng Lin)

指導教授 ： 羅朝村

國立虎尾科技大學/文理學院/生物科技研究所/碩士(2013年)

摘要

瘡痂病菌普遍存在於世界各地，是馬鈴薯病害之重要病原菌之一。雲林縣斗南鎮地區為本省馬鈴薯最重要的生產區；近年來由於馬鈴薯瘡痂病發生率逐漸增加，致使馬鈴薯的產量及外觀皆受到影響，導致市場價格有逐步下降的趨勢。馬鈴薯瘡痂病之病原屬鏈黴菌之一種，不僅危害種薯亦發生在根、莖與匍匐莖，主要病徵為罹病薯於塊莖表面形成邊緣突出，於中央部為稍凹陷之圓形或近圓形之疣狀物並呈現淡褐至灰褐色病斑，嚴重時多數病斑癒合呈網狀龜裂粗皮狀。為有效防除此一病害，本研究旨在探討馬鈴薯瘡痂病之發生及利用枯草桿菌作為生物防治之可行性。
本研究利用自斗南地區所採集之罹病薯塊所分離出之菌株，以做為供試病原菌，將此菌株在 ISP4 (International Streptomyces Project ) 培養基上培養7天，菌落形態呈淡灰白色，並隨著時間而漸轉成褐色並可產孢。為瞭解枯草桿菌對於馬鈴薯瘡痂病防治應用之可行性，本試驗以對峙培養試驗，結果顯示枯草桿菌對於馬鈴薯瘡痂病菌能有效抑制生長；經篩選具拮抗能力優異的BS-9菌株所製作培養發酵液，並行種薯浸泡及澆灌處理，實驗數據亦顯示BS-9菌株確能有效降低瘡痂病病菌之感染及病害之發生率達4~9倍。
在田間試驗中則分成三種處理，即A組將種薯切塊以枯草桿菌BS-9培養液108 cfu/ml稀釋100倍浸泡15分鐘後種植田間，待生長後於第14天再使用BS-9培養液108 cfu/ml稀釋100倍澆灌處理；B組將種薯切塊處理BS-9培養液108 cfu/ml稀釋100倍浸泡15分鐘；C組則是種薯切塊無浸泡菌液等處理，結果顯示：各組平均罹病度及平均罹病面積分別為A組1.15％與1.31 cm2、B組2.21％與3 cm2、C組11.55％與15.8 cm2；各組平均每粒薯重及每公頃總產量，分別為A組126.2 g與42.2公噸、B組122.5 g與39.4公噸、C組109.4 g與36.3公噸。與未處理BS-9之對照組相較，BS-9浸泡及澆灌處理區其植株平均每粒薯重增加7~25％，平均總產量每公頃增加11~28%。顯示BS-9菌株於馬鈴薯瘡痂病病害管理上可達到顯著抑制瘡痂病效果及增加馬鈴薯之產量，實值得推薦於馬鈴薯栽培管理之生物製劑。

關鍵字

枯草桿菌 ； 鏈黴菌 ； 馬鈴薯瘡痂病 ； 生物防治

並列摘要

Streptomyces scabies（Thaxter）Waksman＆Henrici is considered the principal causal agent of potato scab and has wide distribution in world. Yunlin Dounan village has become recently a most important area of potato production in Taiwan. However, the potato common scab has gradually increased since a few years ago and significant economic losses result from reduced marketability since the appearance is important. The symptoms of potato scab lesions on tubers can be quite variable but generally appear as rough, corky lesions, which may range from small to deeply pit. Initially, infections appear as small tan to reddish-brown spots on the tuber surface. Lesions expand as the tubers expand. Tubers with russet scab can have large area superficially covered with corky tissue. Consequently, for reducing potato scab disease, the objective in this study was to determine the occurrence of S. scabies in the major growing area and try to suppress the disease using biological control by Bacillus strains.
The isolate causing common scab symptoms were collected from tubers presenting superficial and raised corky lesions on tubers surface. This isolate of common scab was characterized by creamy colonies on International Streptomyces Project medium (ISP4) and by arial mycelium which tuned brown with age. To determine the suppression ability to potato scab, B. subtilis strain BS-9 was taken to detect on the dual culture. The results indicated that B. subtilis could inhibit the growth of S. scabies in medium tests. The filtrates of B. subtilis cultured in TSB for 5 days also effectively reduced the growth of S. scabies and the disease incidence of potato scab in greenhouse tests as compared untreated control. In the field trials, three treatments including (A) soaking the tubers in the filtrate culture 15 min first and then drenching with filtrate culture after planting for 14 days, (B) soaking tuber in the filtrate culture 15 min only and (C) untreated control. The results revealed that the treatments of (A) and (B) could significantly reduce the disease severity of common scab on potato tubers compared with treatment of (C). The disease severity and infected area of A, B, and C treatment were 1.15% and 1.31 cm2, 2.21% and 3 cm2, 11.55% and 15.8 cm2 receptively. For average weight per tuber and total yield per ha, A, B, and C treatments were 126.2 g and 42.2 ton, 122.5 g and 39.4 ton, 109.4g and 36.3 ton. The results also indicated that treatment A might have 7-25% more weight of per tuber and 11-28% more total yield of per ha than that of untreated control.

並列關鍵字

Bacillus subtilis ； Streptomyces scabies ； potato scab ； biological control

參考文獻

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