黄芩叶斑病病原菌鉴定和药剂室内毒力测定

Pathogens Identification and Fungicides Toxicity Assessment for Scutellaria baicalensis Leaf Spot Disease

为探究黄芩叶斑病的病原种类,筛选有效的杀菌剂,本研究从甘肃省定西市陇西县黄芩主产区采集黄芩叶斑病病叶,采用组织分离法进行病原物的分离,通过病原菌的形态特征并结合rDNA转录间隔区(rDNA-ITS)、过敏原基因(Alt a1)、质膜腺苷三磷酸基因(ATPase)和组蛋白基因(His 3)4个基因序列对病原菌进行种类鉴定,采用菌丝生长速率法测定4种杀菌剂对病原菌的抑菌作用。结果表明,引起陇西县黄芩叶斑病的病原菌为茄链格孢(Alternaria solani)和细极链格孢(Alternaria tenuissima),其中细极链格孢为优势病原菌;室内毒力测定表明,97%咯菌腈的抑菌作用最强,对茄链格孢(A.solani)和细极链格孢(A.tenuissima)均有较好的抑菌作用,EC_(50)分别为0.06和0.04 mg·L^(-1)。本研究在国内首次报道了茄链格孢(A.solani)和细极链格孢(A.tenuissima)是引起黄芩叶斑病的病原菌,可为科学诊断该病害、研究其发生规律和田间防治提供理论基础和科学依据。

In order to determine the pathogen species and screen the effective fungicides for Scutellaria baicalensis leaf spot disease,the leaves infected by spot disease were collected from Longxi county,Dingxi,Gansu province and were used for the isolation of pathogens.The isolates were identified based on their morphological characteristics and the sequences of internal transcription spacer,allergen gene,plasma membrane adenosine triphosphate ATPase and histone 3.The results showed that the disease pathogens were identified as Alternaria solani and Alternaria tenuissima,in which A.tenuissima was the dominant species.Meanwhile,the mycelia growth rate was applied to test the toxicity of four fungicides and 97%Fludioxonil exhibited the strongest inhibitory activity on A.solani and A.tenuissima with EC_(50) at 0.06 and 0.04 mg·L^(-1),respectively.In summary,this is the first report on leaf spot in S.baicalensis caused by A.solani and A.tenuissima in China,which provides a theoretical basis for the diagnosis of disease,understanding of the disease development,prevention and control of the disease in field.