百合叶尖干枯病病原菌的鉴定、生物学特性及其对杀菌剂的敏感性研究

Identification,Biological Characteristics and Sensitivity of the Causal Pathogen Inducing Leaf Dieback on Lily

采集龙牙百合(Lilium brownii var. viridulum)叶尖干枯病典型症状的植株进行病原菌分离、纯化和回接,结合病菌形态学特征及其rDNA-ITS、LSU、TUB和RPB基因的序列分析,确定病原菌为高粱附球菌(Epicoccum sorghinum)。探讨了病原菌对不同碳源、氮源、pH、光照和温度处理等的反应,并采用菌丝生长速率法测定该病原菌对6种杀菌剂的敏感性。研究结果表明,最适合菌丝生长的碳源为乳糖,氮源为牛肉浸膏,pH值为6,温度为25℃,致死温度为48℃,全光照条件有利于菌丝生长。在6种参试杀菌剂中,啶酰菌胺的抑制作用最强,半数效应浓度(concentration for 50%of maximal effect,EC50)为0.011 mg·L^(-1);嘧霉胺的效果最差,EC50为2.168 mg·L^(-1)。

In order to prevent and control the harm effects of leaf dieback of Lilium brownii var. viridulum,diseased plant samples were collected. Isolation and purification of the pathogen were conducted to identify the pathogen. Combining morphological method with molecular identifications of rDNA-ITS,LSU,TUB and RPB genes,the isolated strain was identified as Epicoccum sorghinum. Biological responses of the pathogen to different carbon source,nitrogen source,pH and light treatments also were studied. As a result,the most suitable carbon source was lactose,the most suitable nitrogen source was beef extract,the optimum temperature for the mycelium growth was 25 ℃,and the mycelium death temperature was 48 ℃,the optimum pH value for the mycelium growth was 6,the suitable light condition for the mycelium growth was 24 h. At the aspect of sensitivity to six fungicides,the results revealed that the inhibitory effects had significant differences on the mycelium growth of the pathogen. 50% Carbendazim water dispersible granules(WDG)had stronger inhibitory effect than the others,the concentration for 50% of maximal effect(EC 50 )was 0.011 mg·L^-1 ,40% pyrimethanil suspending agent had the minimum inhibitory effect,with EC 50 value 2.168 mg·L^-1 .