荔枝霜疫霉对烯酰吗啉的抗性风险评估  

Baseline sensitivity and resistance risk assessment of Peronophythora litchii to dimethomorph

作　　者：蓝雯婷 任董董 李瑞环 潘斐 姜子德[1] 潘汝谦[1] 纪春艳 LAN Wenting;REN Dongdonga;LI Ruihuan;PAN Fei;JIANG Zide;PAN Ruqian;JI Chunyan(College of Plant Protection,South China Agricultural University,Guangzhou 510642,Guangdong,China)

机构地区：[1]华南农业大学植物保护学院,广州510642

出　　处：《果树学报》2023年第6期1226-1234,共9页Journal of Fruit Science

基　　金：现代农业产业(荔枝龙眼)技术体系(CARS-32)。

摘　　要：【目的】检测荔枝霜疫霉对烯酰吗啉的敏感性,建立敏感性基线;测定抗烯酰吗啉突变株的生物学适合度,为荔枝霜疫病的化学防治提供依据。【方法】采用菌丝生长速率法,对2019—2020年来自中国广东、广西、福建、四川和云南5个省份荔枝主产区的320株荔枝霜疫霉单孢子囊菌株进行烯酰吗啉敏感性测定,通过药剂驯化获得抗烯酰吗啉突变株,测定其生物学适合度。【结果】经过异常值分析并剔除,317株荔枝霜疫霉菌株对烯酰吗啉的敏感性频率分布呈正态分布,EC_(50)值介于0.0863~0.1733μg·mL^(-1)之间,平均(0.1222±0.0009)μg·mL^(-1),以此建立荔枝霜疫霉对烯酰吗啉的敏感性基线。来自2020年的荔枝霜疫霉菌株对烯酰吗啉的EC_(50)均值较2019年显著增高。3株荔枝霜疫霉抗烯酰吗啉突变株的抗性指数介于77.17~360.11之间,为中到高抗水平,抗药性可稳定遗传,与亲本相比,抗性突变株的孢子囊萌发率及卵孢子产量均下降,但致病力相当。【结论】荔枝霜疫霉对烯酰吗啉敏感,烯酰吗啉可继续作为防治荔枝霜疫病的有效杀菌剂。【Objective】Litchi downy blight caused by peronophythora litchii is a devastating disease,which seriously affects the quality and yield of litchi.With the continuous use of fungicides,the effectiveness of fungicides has been threatened by the emergence of resistant pathogens.Dimethomorph is a CAAs fungicide,which has been widely used for controlling litchi downy blight for many years.Up to now,few studies on the sensitivity of P.litchii to dimethomorph have been reported.The resistance risk of P.litchii to dimethomorph is still largely unknown.The objective of this study is to(i)establish the baseline sensitivity of P.litchii isolates collected from five provinces or autonomous region(Guangdong,Guangxi,Fujian,Yunnan and Sichuan)to dimethomorph.(ii)obtain the dimethomorph-resistant mutants by fungicide adaption,and investigate the biological fitness of resistant mutants.The results might provide scientific guidance for highly effective dimethomorph use in controlling litchi downy blight.【Methods】A total of 320 P.litchii isolates were obtained from diseased fruits from Guangdong,Guangxi,Fujian,Yunnan and Sichuan provinces or autonomous region of China during 2019 to 2020.Growing mycelia assay in vitro was used to determine the median effective concentration(EC_(50))values of P.litchii isolates to dimethomorph.Technical grade dimethomorph(a.i.99.0%)was dissolved in dimethyl sulfoxide.The solution was diluted to different concentrations.Mycellium plugs(5-mm-diameter)were cut from the fresh growing edge of a 4-day-old P.litchii colony,and placed on carrot agar medium plates(90-mm-diameter)amended with 0.05,0.1,0.15,0.2,0.25,0.3 mg·mL-1 dimethomorph.Three replicates were determined for each concentration.Mycelial growth was measured after 5 days incubation at 25℃in darkness.The EC_(50) value for each isolate was calculated by regression analysis using the percentage of growth inhibition against the logarithmic value of dimethomorph concentration.Kolmogorov-smirnov test was used to check the normal distributio

关 键 词：荔枝霜疫霉 烯酰吗啉 敏感性 抗性突变株 

分 类 号：S667.1[农业科学—果树学]