Wang Yanfen, Lu Ninghai, Wang Kuaikuai, Li Yinna, Zhang Mengli, Liu Shuang, Li Yanling, Zhou Feng
School of Resources and Environment, Henan Institute of Science and Technology, Xinxiang 453003, China.
College of Plant Protection, Henan Agricultural University, Zhengzhou 450002, China.
Plant Dis. 2023 Apr;107(4):1035-1043. doi: 10.1094/PDIS-07-22-1615-RE. Epub 2023 Apr 19.
The necrotrophic pathogen has a global distribution and a wide host range, making it one of the most damaging and economically important of all plant pathogens. The current study found that fluxapyroxad, a typical succinate dehydrogenase inhibitor fungicide, had a strong inhibitory effect against , with mean effective concentration for 50% inhibition (EC) values ranging from 0.021 to 0.095 µg/ml. Further investigation of five highly resistant mutants, with EC values of 12.37 to 31.36 µg/ml, found that fluxapyroxad resistance was accompanied by a certain cost to fitness. All of the mutants were found to have significantly ( < 0.05) reduced mycelial growth and altered sclerotia production in artificial culture, as well as reduced pathogenicity, compared with wild-type isolates, with one mutant completely losing the capacity to infect detached soybean leaves. Sequence analysis demonstrated that four of the mutants had point mutations leading to amino acid changes in the SsSdhB subunit of the fungicide target protein succinate dehydrogenase. In addition, two of the mutants were also found to have amino acid changes in the predicted sequence of their SsSdhD subunit, while the fifth mutant had no changes in any of its SsSdh sequences, indicating that an alternative mechanism might be responsible for the observed resistance in this mutant. No cross-resistance was found between fluxapyroxad and any of the other fungicides tested, including tebuconazole, prochloraz, dimethachlone, carbendazim, procymidone, pyraclostrobin, boscalid, fluazinam, fludioxonil, and cyprodinil, which indicates that fluxapyroxad has great potential as an alternative method of control for the Sclerotinia stem rot caused by , and which could provide ongoing protection to the soybean fields of China.
这种坏死营养型病原菌分布于全球，寄主范围广泛，是所有植物病原菌中危害最大且在经济上最重要的病原菌之一。当前研究发现，典型的琥珀酸脱氢酶抑制剂类杀菌剂氟唑菌酰胺对[病原菌名称未给出]具有强烈抑制作用，50%抑制的平均有效浓度（EC）值范围为0.021至0.095微克/毫升。对五个高抗氟唑菌酰胺的突变体（EC值为12.37至31.36微克/毫升）进一步研究发现，对氟唑菌酰胺的抗性伴随着一定的适合度代价。与野生型分离株相比，所有突变体在人工培养中均表现出菌丝生长显著降低（P<0.05）、菌核产生改变以及致病性降低，其中一个突变体完全丧失了感染离体大豆叶片的能力。序列分析表明，四个突变体在杀菌剂靶蛋白琥珀酸脱氢酶的SsSdhB亚基中存在导致氨基酸变化的点突变。此外，还发现其中两个突变体在其SsSdhD亚基的预测序列中也有氨基酸变化，而第五个突变体在其任何SsSdh序列中均无变化，这表明可能存在另一种机制导致该突变体产生观察到的抗性。在氟唑菌酰胺与所测试的任何其他杀菌剂之间未发现交叉抗性，这些杀菌剂包括戊唑醇、咪鲜胺、异菌脲、多菌灵、腐霉利、吡唑醚菌酯、啶酰菌胺、氟啶胺、咯菌腈和嘧菌环胺，这表明氟唑菌酰胺作为防治由[病原菌名称未给出]引起的菌核病的替代防治方法具有巨大潜力，可为中国的大豆田提供持续保护。
