龙牙百合褐斑病病原的鉴定、生物学特性及室内药剂筛选

Identification,Characterization the Leaf Brown Spot Pathogen in Lilium brownii var.viridulum and Screening Fungicides against Alternaria arborescens

为明确龙牙百合褐斑病病原,采集龙牙百合褐斑病典型症状的叶片,进行病原物分离、纯化和致病性测定,结合病原菌形态学观察及其rDNA-ITS、gapdh、tef1、RPB2和Alt a1等基因的序列分析,确定引起龙牙百合褐斑病的病原菌为枝状链格孢Alternaria arborescens。采用菌丝生长速率法,测定了光照、温度、pH值、碳源、氮源和不同培养基等处理对该病原菌生长的影响,并测定了病原菌对7种杀菌剂的敏感性。结果表明,最适合菌丝生长的条件为温度25℃,pH值5.0,碳源为蔗糖,氮源为牛肉浸膏,培养基为马铃薯葡萄糖琼脂(PDA)培养基;菌落致死温度为50℃。在7种参试药剂中,木霉菌抑制作用最强,其半数效应浓度(EC_(50))和90%效应浓度(EC_(90))值最低,分别是8.758×10^(-5)和0.198 mg·L^(-1);噁唑菌酮代森锰锌的毒力最低,EC_(50)和EC_(90)值分别为13.713和816.937 mg·L^(-1)。本研究结果为龙牙百合褐斑病菌的精准防控提供了理论依据。

In order to identify the pathogen causing brown spot in Lilium brownii var.viridulum,leaves with typical symptoms were collected and utilized for the isolation,purification and pathogenicity assessment of the pathogen.The pathogen was identified as Alternaria arborescens through morphological observation and sequence analysis of rDNA-ITS,gapdh,tef1,RPB2,and Alt a1 genes.Influence factors such as light intensity,temperature,pH value,carbon source,nitrogen source,and various culture media on A.arborescens growth were investigated using the mycelial growth rate method.Additionally,the sensitivity of the pathogen to seven fungicides was determined.The results indicated that the optimal conditions for mycelial growth were at 25℃,pH value 5.0,sucrose as the carbon source,beef extract as the nitrogen source,and PDA as the culture medium.The lethal temperature of the pathogen was 50℃.Among the tested fungicides,Trichoderma exhibited the strongest inhibitory effect,with the lowest EC_(50) and EC_(90) values of 8.758×10^(-5) and 0.198 mg·L^(-1),respectively.Conversely,that of famoxadone·mancozeb was the lowest,with EC_(50) and EC_(90) being of 13.713 and 816.937 mg·L^(-1),respectively.This study provides a theoretical basis for the precise prevention and control of brown spot disease in Lilium brownii var.viridulum.