苹果轮纹病菌对戊唑醇的敏感性及其抗性突变体的致病力

摘要

为明确苹果轮纹病菌对戊唑醇的敏感性及其抗性突变体的致病力，采用菌丝生长速率法测定了130株苹果轮纹病菌菌株对戊唑醇的敏感性，采用药剂驯化和紫外线诱导的方式获得抗性突变体，并研究其生存适合度。结果表明，戊唑醇对130个菌株的EC50分布在0.051 6～1.925 4 μg/mL，均值为（0.799 6±0.039 1）μg/mL，表明苹果轮纹病菌开始出现敏感性下降的亚群体。供试苹果轮纹病菌菌株的抗性频率为71.54%，各省份均未出现高抗菌株。药剂驯化、紫外诱导共获得3株抗性倍数分别为58.82倍、41.60倍、38.19倍的高抗菌株。抗性突变体致病力、适合度指数与敏感菌株相比没有显著性差异。无药培养9代后，各抗性突变体EC50逐渐下降，所获抗性可能不能稳定遗传。表明苹果轮纹病菌对戊唑醇的抗性在田间自然选择压力下可能会逐渐降低。

关键词

苹果轮纹病菌；戊唑醇；敏感性；突变体；致病力

中图分类号：

S482.2

文献标识码：A

DOI：10.3969/j.issn.05291542.2017.01.024

Abstract

130 Botryosphaeria dothidea isolates were collected from major appleproduced regions to assess the susceptibility to tebuconazole by mycelium growth rate method and to test the virulence of resistance mutants. Resistant mutants were obtained by chemical screening and UV irradiation in the laboratory， and the fitness parameters of resistant and susceptible isolates were measured. The results showed that the EC50 values of 130 isolates varied from 0.051 6-1.925 4 μg/mL with the mean of （0.799 6±0.039 1）μg/mL and low resistant subcolony has been discovered. The resistant ratio of tested isolates was 71.54% and highresistant strains has not discovered in major appleproduced regions. The resistance level of three resistant mutants was high with the resistant ratio of 58.82， 41.60 and 38.19 times， respectively. The fitness and virulence of resistant mutants had no significant difference between resistant and susceptible isolates. The resistance ratio of mutants decreased gradually after 9 generations of subcultures in the absence of fungicides and the resistance could not inherit stably. The results indicated that the resistance of B.dothidea to tebuconazole could gradually decline when the field selection pressure became lower.

Key words

Botryosphaeria dothidea；tebuconazole；susceptibility；mutant；pathogenicity

三唑類杀菌剂是20世纪70年代中后期开发的一类新型广谱杀菌剂，是杀菌剂发展史上里程碑式的创新，历经几十年的发展，在杀菌剂市场中的销售份额位列第一[12]。戊唑醇的作用机理是抑制真菌麦角甾醇中间体的氧化脱甲基反应，具有内吸、高效、广谱、安全等特点[3]，对链格孢属Alternaria、疫霉属Phytophthora、黑星菌属Venturia、白粉菌属Erysiphe、镰刀菌属Fusarium、柄锈菌属Puccinia、喙孢属Rhynchosporium、尾孢属Cercospora、丛赤壳属Nectria、核腔菌属Pyrenophora 、壳针孢菌属Septoria、灰葡萄孢属Botrytis引起的病害均有良好的防治效果[45]。该药20世纪90年代中期正式在中国苹果树上登记使用[6]，对苹果轮纹病具有优良的防治效果[5]，近年来一直是防治苹果轮纹病的首选药剂。

戊唑醇因其强选择性和作用位点专一性，使用中可能会导致病原菌产生抗药性。据报道葡萄灰霉病菌Botrytis cinerea[7]、大麦云纹病菌Rhynchosporium secalis[8]、开心果枝枯病菌Botryosphaeria dothidea[9]、桃褐腐病菌Monilinia fructicola[10]、禾谷镰刀菌Fusarium graminearum[11]、红球丛赤壳菌Nectria haematococca[12]等病原菌均对戊唑醇产生了不同程度的抗性。目前，尚未见到关于苹果轮纹病菌Botryosphaeria dothidea对戊唑醇产生抗性的报道，因此，本研究2013年采集了我国主要苹果产区苹果轮纹病菌，并测定了其对戊唑醇的敏感性，比较室内诱导的抗药性突变体与敏感菌株的适合度，以期预测该病原菌群体抗性发展趋势，为制定正确的防治策略及指导生产用药提供依据。

推荐访问:抗性 敏感性 病菌 致病 苹果