Luo Qiuchen, Schoeneberg Anita, Hu Mengjun
Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742.
Plant Dis. 2021 Aug;105(8):2202-2208. doi: 10.1094/PDIS-09-20-2048-RE. Epub 2021 Sep 15.
Multiple species have been found to be responsible for strawberry anthracnose, and prevalence of each species seems to vary by regions and/or host tissues. In this study, a total of 200 isolates were obtained from different strawberry cultivars displaying anthracnose symptoms in the mid-Atlantic fields. Analysis of , and/or internal transcribed spacer sequences revealed four species, including , , , and . was the predominant species, representing 90% of all isolates collected. This species was found from all strawberry organs/tissues examined, whereas and were limited to the crown and fruit, respectively. Further, all isolates were screened for resistance to azoxystrobin in vitro, and all isolates were additionally screened for resistance to thiophanate-methyl. The overall frequency of resistance to azoxystrobin and thiophanate-methyl was 48 and 67%, respectively. G143A in the cytochrome gene was found in all and . isolates with high level of resistance, with EC >100 µg/ml, while F129L was found in two of the five isolates with moderate resistance, with EC values ranging from 2.6 to 7.8 µg/ml. All isolates tested were found to be less sensitive to azoxystrobin, with EC values ranging from 9.7 to 14.4 µg/ml, despite no mutations detected in the cytochrome gene. Moreover, E198A in was linked with isolates resistant to thiophanate-methyl (EC >100 µg/ml). These results revealed that resistance in spp. to primary fungicides is widespread in the mid-Atlantic strawberry fields.
已发现多种物种可导致草莓炭疽病，且每种物种的流行情况似乎因地区和/或寄主组织而异。在本研究中，从大西洋中部田间表现出炭疽病症状的不同草莓品种中总共获得了200个分离株。对……和/或内部转录间隔区序列的分析揭示了4种物种，包括……、……、……和……。……是主要物种，占所有收集分离株的90%。在所有检测的草莓器官/组织中均发现了该物种，而……和……分别局限于冠部和果实。此外，对所有分离株进行了体外抗嘧菌酯筛选，对所有分离株还进行了抗甲基硫菌灵筛选。对嘧菌酯和甲基硫菌灵的总体抗性频率分别为48%和67%。在所有……和……具有高水平抗性（EC>100μg/ml）的分离株中发现了细胞色素……基因中的G143A，而在5个具有中等抗性（EC值范围为2.6至7.8μg/ml）的……分离株中有2个发现了F129L。尽管在细胞色素……基因中未检测到突变，但所有测试的……分离株对嘧菌酯均不太敏感，EC值范围为9.7至14.4μg/ml。此外，……中的E198A与对甲基硫菌灵抗性的……分离株（EC>100μg/ml）有关。这些结果表明，…… spp. 对主要杀菌剂的抗性在大西洋中部草莓田广泛存在。
