Ishii Hideo, Watanabe Hideki, Yamaoka Yuichi, Schnabel Guido
University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki 305-8572, Japan; Clemson University, 105 Collings Street, Clemson, SC 29634, USA; Kibi International University, Sareo 370-1, Shichi, Minami-awaji, Hyogo 656-0484, Japan.
Gifu Prefectural Agricultural Technology Centre, Matamaru, Gifu, Gifu 501-1152, Japan.
Pestic Biochem Physiol. 2022 Mar;182:105049. doi: 10.1016/j.pestbp.2022.105049. Epub 2022 Jan 26.
Colletotrichum species cause diseases on many plants and are among the 'top 10' fungal plant pathogens. Species of the C. gloeosporioides and C. acutatum complexes are particularly important because they infect temperate fruit crops, but their control relies largely on chemical fungicides. In this study, differences in intrinsic fungicide sensitivity were determined in vitro using isolates of the C. gloeosporioides sp. complex (C. fructicola, C. siamense, and C. tropicale) and the C. acutatum sp. complex (C. fioriniae and C. nymphaeae), which had never been exposed to fungicides. Mycelial growth of all isolates was sensitive to the QoI azoxystrobin, the SDHI benzovindiflupyr, and the new DMI fungicide mefentrifluconazole. The isolates of C. nymphaeae were highly sensitive to the phenylpyrrole fungicide fludioxonil. The isolates of C. gloeosporioides sp. complex were sensitive to the bis-guanidine fungicide iminoctadine-albesilate, whereas those of C. acutatum sp. complex were inherently insensitive. These results are valuable when sensitivity of field populations is monitored in resistance management. Although SDHI fungicides are largely not effective against diseases caused by Colletotrichum species, benzovindiflupyr controlled anthracnose disease of various crops such as kidney bean, garland chrysanthemum, and strawberry, caused by C. lindemuthianum, C. chrysanthemi, and C. siamense, respectively, demonstrating this fungicide to be unique among SDHIs and having a broad control spectrum against anthracnose. To help understanding the reason for differential activity of benzovindiflupyr and boscalid, sdhB gene sequences were analyzed but those of C. lindemuthianum, C. chrysanthemi, and C. scovillei revealed no known mutations reported to be responsible for SDHI resistance in other fungi, indicating that other mechanism(s) than target-site modification may be involved in differential sensitivity to benzovindiflupyr and boscalid, found in Colletotrichum species.
炭疽菌属的物种可引发多种植物病害，是“十大”真菌类植物病原体之一。胶孢炭疽菌复合种和尖孢炭疽菌复合种的物种尤为重要，因为它们会感染温带水果作物，但其防治很大程度上依赖化学杀菌剂。在本研究中，使用从未接触过杀菌剂的胶孢炭疽菌复合种（果生炭疽菌、暹罗炭疽菌和热带炭疽菌）及尖孢炭疽菌复合种（费奥里尼炭疽菌和睡莲炭疽菌）的分离株，在体外测定了内在杀菌剂敏感性差异。所有分离株的菌丝生长对醌类抑制剂（QoI）嘧菌酯、琥珀酸脱氢酶抑制剂（SDHI）苯并烯氟菌唑以及新型脱甲基化抑制剂（DMI）杀菌剂联苯三唑醇敏感。睡莲炭疽菌的分离株对苯基吡咯类杀菌剂咯菌腈高度敏感。胶孢炭疽菌复合种的分离株对双胍类杀菌剂亚胺菌敏感，而尖孢炭疽菌复合种的分离株则天生不敏感。在抗性管理中监测田间种群的敏感性时，这些结果很有价值。虽然SDHI类杀菌剂在很大程度上对炭疽菌属物种引起的病害无效，但苯并烯氟菌唑可防治分别由菜豆炭疽菌、菊芋炭疽菌和暹罗炭疽菌引起的多种作物如菜豆、茼蒿和草莓的炭疽病，表明该杀菌剂在SDHI类中具有独特性，且对炭疽病具有广泛的防治谱。为了有助于理解苯并烯氟菌唑和啶酰菌胺活性差异的原因，分析了sdhB基因序列，但菜豆炭疽菌、菊芋炭疽菌和斯氏炭疽菌的序列未显示出其他真菌中报道的与SDHI抗性相关的已知突变，这表明除了靶标位点修饰之外，其他机制可能参与了炭疽菌属物种对苯并烯氟菌唑和啶酰菌胺的敏感性差异。
