College of Agriculture and Food Science, Zhejiang A&F University, Lin'an, Zhejiang 311300, People's Republic of China.
Jinhua Academy of Agricultural Sciences, Jinhua, Zhejiang 3210127, People's Republic of China.
Plant Dis. 2020 Apr;104(4):1151-1157. doi: 10.1094/PDIS-05-19-1031-RE. Epub 2020 Feb 13.
In 2017 and 2018, a total of 294 isolates were collected from bakanae-diseased rice plants in Jinhua, Shaoxing, and Jiaxing in Zhejiang Province, China. Phenamacril sensitivity of these isolates was determined by the 50% effective concentration value or minimum inhibitory concentration methods. Our results indicated that the phenamacril resistance frequency of increased from 18% in 2017 to 47% in 2018, and rice plants infected with -resistant isolates could not be protected effectively with 50 mg/liter of phenamacril. Phenamacril-resistant isolates obtained from rice fields showed stable resistance, because their fitness levels (i.e., mycelial growth, sporulation, and pathogenicity) were similar to the phenamacril-sensitive isolates. In addition to the point mutation at codon 219 in the - gene that conferred resistance to phenamacril, our results also showed another point mutation at codon 218 (AAG→ACG) in -5 that also conferred resistance to phenamacril. In this study, we found rapid development and persistence of diversified genotypes of phenamacril resistance, highlighting the importance of proper use of phenamacril in rice fields. Our results may also help researchers develop new fungicides or new control strategies using combinations of different fungicides in the control of phenamacril-resistant isolates.
2017 年和 2018 年，在中国浙江省金华、绍兴和嘉兴的恶苗病水稻植株上共采集了 294 个分离株。采用 50%有效浓度值或最小抑菌浓度法测定这些分离株对苯霜灵的敏感性。结果表明，苯霜灵的抗性频率从 2017 年的 18%增加到 2018 年的 47%，用 50mg/L 苯霜灵处理感染 -抗性分离株的水稻植株不能得到有效保护。从稻田中获得的苯霜灵抗性 分离株表现出稳定的抗性，因为它们的适应性水平（即菌丝生长、孢子形成和致病性）与苯霜灵敏感分离株相似。除了 -基因 219 密码子的点突变导致对苯霜灵的抗性外，我们的结果还显示 -5 中另一个密码子 218（AAG→ACG）的点突变也导致对苯霜灵的抗性。在本研究中，我们发现苯霜灵抗性的多样化基因型快速发展和持续存在，突出了在稻田中合理使用苯霜灵的重要性。我们的结果也可能有助于研究人员在控制苯霜灵抗性 分离株时，利用不同杀菌剂的组合开发新的杀菌剂或新的控制策略。
