College of Plant Protection, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
College of Plant Protection, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
Pestic Biochem Physiol. 2018 Nov;152:98-105. doi: 10.1016/j.pestbp.2018.09.010. Epub 2018 Sep 20.
Fusarium fujikuroi is the primary causal agent of rice bakanae disease. Fluazinam is a protective dinitroaniline fungicide which could interrupt the fungal cell's energy production. Little is known about the effects of fluazinam on F. fujikuroi. In this study, baseline sensitivity of F. fujikuroi to fluazinam was determined using 103 isolates collected from diseased young rice of different fields in Shaoxing of Zhejiang Province and Huaian of Jiangsu Province of China in 2016. The EC values of fluazinam on inhibiting mycelial growth against 103 isolates of F. fujikuroi ranged from 0.0621 to 0.5446 μg/mL with the average value of 0.2038 ± 0.0099 μg/mL (mean ± standard error). The EC values of fluazinam on suppressing conidium germination against 103 isolates of F. fujikuroi ranged from 0.1006 to 0.9763 μg/mL with the mean value of 0.3552 ± 0.0181 μg/mL. Treated with fluazinam, hyphae of F. fujikuroi were contorted, offshoot of top mycelia increased, conidial production descreased significantly and exopolysaccharide (EPS) content did not change significantly while peroxidase (POD) activity significantly decreased. Meanwhile, cell membrane permeability increased after treated with fluazinam. The analysis of cell ultrastructure indicated that fluazinam could damage the membrane structure of F. fujikuroi and cause a large number of vacuoles formed. In addition, fluazinam did not affect germination rate, plant height and fresh weight of rice, which indicated that fluazinam was safe to rice. All the results indicated that fluazinam had strong antifungal activity against F. fujikuroi and a potential application in controlling rice bakanae disease. These results will provide useful information for management of rice bakanae disease caused by F. fujikuroi and further increase our understanding about the mode of action of fluazinam against F. fujikuroi and other phytopathogens.
镰刀菌（Fusarium fujikuroi）是水稻恶苗病的主要致病菌。氟唑菌苯胺是一种保护性二硝基苯胺类杀菌剂，可以阻断真菌细胞的能量产生。目前对于氟唑菌苯胺对镰刀菌（F. fujikuroi）的影响知之甚少。本研究于 2016 年采集来自中国浙江绍兴和江苏淮安不同稻田发病秧苗的 103 个镰刀菌（F. fujikuroi）分离物，采用菌丝生长速率法测定了氟唑菌苯胺对镰刀菌（F. fujikuroi）的基础敏感性。氟唑菌苯胺对抑制 103 个镰刀菌（F. fujikuroi）分离物的菌丝生长的 EC 值范围为 0.0621-0.5446μg/mL，平均值为 0.2038±0.0099μg/mL（平均值±标准误差）。氟唑菌苯胺对抑制 103 个镰刀菌（F. fujikuroi）分离物的分生孢子萌发的 EC 值范围为 0.1006-0.9763μg/mL，平均值为 0.3552±0.0181μg/mL。用氟唑菌苯胺处理后，镰刀菌（F. fujikuroi）的菌丝扭曲，顶生菌丝分枝增多，产孢量显著减少，胞外多糖（EPS）含量无明显变化，而过氧化物酶（POD）活性显著降低。同时，经氟唑菌苯胺处理后，细胞膜通透性增加。细胞超微结构分析表明，氟唑菌苯胺能破坏镰刀菌（F. fujikuroi）的膜结构，导致大量空泡形成。此外，氟唑菌苯胺不影响水稻的发芽率、株高和鲜重，这表明氟唑菌苯胺对水稻是安全的。所有结果表明，氟唑菌苯胺对镰刀菌（F. fujikuroi）具有很强的抑菌活性，在防治水稻恶苗病方面具有潜在的应用价值。这些结果将为镰刀菌（F. fujikuroi）引起的水稻恶苗病的防治提供有用的信息，并进一步提高我们对氟唑菌苯胺对镰刀菌（F. fujikuroi）及其他植物病原菌作用方式的认识。
