大别山区3种鸢尾科药材白绢病病原鉴定及其生物学特性

为明确大别山区射干、鸢尾、蝴蝶花3种鸢尾科药材白绢病病原菌种类及其生物学特性,该文根据柯赫法则对鸢尾科白绢病病原菌进行了分离、鉴定、致病性测定并对其生物学特性进行了研究,此外,采用菌丝生长速率法测定了9种化学杀菌剂、3种植物源杀菌剂和5种微生物菌剂对白绢病菌的抑制作用。结果表明:从射干、鸢尾、蝴蝶花感病植株分离得到的SG-Q,YW-Q,HDH-Q菌株通过形态鉴定,18S rDNA,rDNA-ITS以及TEF序列分子鉴定均为齐整小核菌Sclerotium rolfsii。通过田间调查及回接实验表明3种鸢尾科药材白绢病田间发病率是射干>蝴蝶花>鸢尾,菌株致病力强弱则是SG-Q>YW-Q>HDH-Q。在不同培养条件下白绢病菌菌株SG-Q适宜在12 h光照/12 h黑暗条件下生长,最适生长温度为30℃,最适生长pH为5。9种化学杀菌剂中29%石硫合剂和10%氟硅唑对病原菌SG-Q菌丝生长具有很好的抑制作用;3种植物源杀菌剂1%蛇床子素、20%丁子香酚、0.5%小檗碱均对SG-Q菌丝生长具有抑制作用,且可使该菌菌丝形态发生变化;5种微生物菌剂中哈茨木霉菌和枯草芽孢杆菌对SG-Q菌丝生长具有较好抑制作用。

Identification and biological characteristics of southern blight causing root rot on three medicine plants of Iridaceae in Dabie Mountains

In order to identify the species and biological characteristics of the pathogen of southern blight from three kinds of Chinese medicine of Iridaceae(Belamcanda chinensis,Iris tectorum and I.japonica)in Dabie Mountains,the isolation,identification,pathogenicity and biological characteristics of the pathogens were studied according to Koch′s postulates.In addition,9 chemical fungicides,3 botanical fungicides and 5 microbial fungicides were used to evaluate their inhibition to the isolates in vitro.The results showed that all the strains(SG-Q,YW-Q,and HDH-Q)isolated and purified from the diseased plants of B.chinensis,I.tectorum and I.japonica,respectively,were identified as Sclerotium rolfsii through morphological observation and sequence aligement of 18 S rDNA,rDNA-ITS and TEF.Field observations showed that the intensity of the disease incidence of three Iridaceae plants was B.chinensis>I.japonica>I.tectorum,and the pathogenicity of the strains was SG-Q>YW-Q>HDH-Q.For biological characteristics,SG-Q strain was suitable for growth under the 12 h light/12 h dark cycle,with the optimal growth temperature of 30℃and pH of 5.Among the 9 tested chemical fungicides,29%lime sulphure and 10%flusilazole had stronger inhibitory effect on mycelia growth of SG-Q.For 3 botanical fungicides,1%osthol,20%eugenol and 0.5%berberine could effectively inhibt the mycelial growth of SG-Q and cause the morphological variation of the pathogen.For 5 microbial fungicides,Trichoderma harzianum and Bacillus subtilis had better inhibition on the mycelium growth of SG-Q.