College of Plant Protection, Nanjing Agricultural University, Nanjing, Jiangsu, China.
College of Plant Protection, Henan Agricultural University, Zhengzhou, Henan, China.
Plant Dis. 2024 Mar;108(3):658-665. doi: 10.1094/PDIS-07-23-1374-RE. Epub 2024 Mar 8.
Gummy stem blight, caused by , is an important disease in watermelon in China. Fluxapyroxad, a new succinate dehydrogenase inhibitor fungicide, shows strong inhibition of the mycelia growth of . However, its resistance risk in . is unclear. In this research, the sensitivities of 60 strains to fluxapyroxad were investigated. The average EC value and MIC values of 60 strains 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 were significantly lower than those of their parental strains. However, four resistant mutants showed a similar phenotype in pathogenicity compared with their parental strains. The above results demonstrated that there was a medium resistance risk for fluxapyroxad in . The 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 and further increase our understanding about the mode of action of fluxapyroxad.
胶质茎枯病，由 引起，是中国西瓜的重要病害。氟吡菌酰胺，一种新型琥珀酸脱氢酶抑制剂类杀菌剂，对 的菌丝生长具有较强的抑制作用。然而，其在 中的抗药性风险尚不清楚。本研究对 60 株 进行了对氟吡菌酰胺的敏感性测定。60 株菌对氟吡菌酰胺的平均 EC 值和 MIC 值分别为 0.022±0.003μg/ml 和≤0.1μg/ml，用于菌丝生长。从三个野生型亲本菌株中获得了 8 株具有中等抗性水平的氟吡菌酰胺抗药性突变体。大多数突变体的菌丝生长和菌丝干重明显低于其亲本菌株。然而，有 4 个抗性突变体在致病性方面表现出与亲本菌株相似的表型。上述结果表明，在 中存在氟吡菌酰胺的中度抗药性风险。交叉抗性试验表明，氟吡菌酰胺与吡氟酰草胺、噻呋酰胺和啶氧菌酯之间存在正交叉抗性，但氟吡菌酰胺与戊唑醇和嘧菌酯之间不存在交叉抗性。这些结果将有助于评估氟吡菌酰胺防治 引起的病害的抗药性风险，并进一步提高我们对氟吡菌酰胺作用模式的认识。
