细辛篮状菌叶枯病病原鉴定及室内防控药剂筛选

Identification of the pathogen causing asarum leaf blight and screening of effective fungicides

采用组织分离法,对采自辽宁抚顺新宾的细辛叶枯病株进行病原分离和纯化。根据柯赫氏法则,对分离菌株进行致病性测定。通过形态学观察,结合rDNA-ITS序列分析,以及BenA与RPB2多基因位点序列对比分析,对病原菌进行鉴定。结果表明:经回接验证,明确分离所获菌株是细辛叶枯病的致病菌;代表性菌株XXY-2的形态特征以及在OA、MEA、DG18、YES、CYA和CREA等6种培养基上的菌落培养特征与Talaromyces brevis一致;基于ITS-BenA-RPB2多基因序列系统发育分析结果显示,XXY-2与T.brevis的模式菌株DTO 307T和CBS 141833T处于同一分支,自展值为100,表明XXY-2为T.brevis。采用菌丝生长速率法,测定8种杀菌剂对T.brevis生长的抑制效果,其中吡唑醚菌酯和氟啶胺的室内抑菌效果最好,EC50值分别为0.0096和0.0056μg·mL-1。这是T.brevis作为细辛叶枯病病原的首次报道,为后续开展细辛叶枯病综合防治奠定了理论基础。

Asarum plants showing leaf blight symptoms were collected from Xinbin County,Fushun City,Liaoning Province,China.To investigate the causal agent of the disease,pathogenicity test was carried out with XXY-2,a representative fungal strain that were isolated from the diseased plant tissues,and the result showed that it is the pathogen causing asarum leaf blight.Based on morphological characters,strain XXY-2 was identified as Talaromyces brevis.According to the results of multigene-combined(rDNA-ITS+BenA+RPB2)phylogenetic analysis,strain XXY-2 was grouped into the same branch of T.brevis model strains DTO 307T and CBS 141833T,further confirming that it belongs to T.brevis.Indoor toxicity tests of 8 fungicides against strain XXY-2 showed that pyraclostrobin and fludioxonil had a better inhibitory effect on mycelial growth of the strain,with EC50 values of 0.0096 and 0.0056μg·mL-1,respectively.This is the first report of T.brevis as a pathogen of asarum leaf blight,making a theoretical basis for integrated control of the disease.