Bioactivity and Resistance Risk of Fluxapyroxad, a Novel SDHI Fungicide, in Didymella bryoniae
Bioactivity and Resistance Risk of Fluxapyroxad, a Novel SDHI Fungicide, in Didymella bryoniae
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DOI：
10.1094/pdis-07-23-1374-re
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发表时间：
2024-03-08
期刊：
影响因子：
4.5
通讯作者：
Hou，Yiping
中科院分区：
文献类型：
--
作者：
Mao，Xuewei;Wu，Zhiwen;Hou，Yiping
甜瓜树干枯萎病是中国西瓜上的一种重要病害，由苔藓迪氏菌引起。新型琥珀酸脱氢酶抑制剂氟喹诺酮对棉铃虫菌丝生长有较强的抑制作用。然而，其在金黄色葡萄球菌中的抗药性风险尚不清楚。本研究对60株金黄色葡萄球菌对氟沙培南的敏感性进行了研究。对菌丝生长的EC50值和MIC值分别为0.022±0.003μg/m L和≤0.1μg/m L。从3个野生型亲本菌株中筛选到8个中抗性突变体。多数突变体的菌丝生长和菌丝干重均显著低于其亲本菌株。然而，大多数抗性突变体与其亲本相比，在致病性和对胁迫的敏感性方面表现出相似的表型。以上结果表明，白粉菌对氟喹诺酮存在中等抗性风险。交叉耐药试验表明，氟喹诺酮与吡虫啉、硫磺酰胺与博斯卡利特呈正交叉耐药，与戊唑醇、甲虫腈无交叉耐药性。这些结果将有助于评估氟喹诺酮治疗苔藓螺旋体引起的疾病的耐药性风险，并进一步加深我们对氟喹诺酮作用机制的了解。
Gummy stem blight (GSB), caused by Didymella bryoniae, is an important disease of watermelon in China. Fluxapyroxad, a new succinate dehydrogenase inhibitor fungicide, shows a strong inhibition of the mycelia growth of D. bryoniae. However, its resistance risk in D. bryoniae is unclear. In this research, the sensitivities of 60 D. bryoniae strains to fluxapyroxad were investigated. The average EC50 value and MIC values of 60 D. bryoniae against fluxapyroxad were 0.022±0.003 μg/mL and≤ 0.1 μg/mL for mycelial growth, respectively. Eight fluxapyroxad-resistant mutants with medium resistance levels were acquired from three wild type parental strains. The mycelial growth and dry weight of mycelia of most mutants was significantly lower than that of their parental strains. However, most resistant mutants showed similar phenotype in pathogenicity and sensitivity to stresses compared with their parental strain. The above results demonstrated that there was a medium resistance risk for fluxapyroxad in D. bryoniae. Cross resistance assay showed that there was positive cross-resistance between fluxapyroxad and pydiflumetofen, thifluzamide and boscalid, but there was no cross-resistance between fluxapyroxad and tebuconazole and mepronil. These results will contribute to evaluating the resistance risk of fluxapyroxad for managing diseases caused by D. bryoniae and further increase our understanding about the mode of action of fluxapyroxad.