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Abstract：
Bletilla striata is an endangered traditional medicinal herb in China. In May 2020, the emergence of white root rot severely impacted the quality and yield of B. striata, affecting about 5% of the plants at plant nurseries of the Chengdu Academy of Agricultural and Forestry Sciences. Through a series of experiments and evaluations, the pathogen was identified as Fusarium solani. This is the first report of B. striata white root rot caused by F. solani in Sichuan, China. To better understand this disease and provide data support for its control, a combination of morphological, molecular characterisation and pathogenicity determination was used in this study for assessment. Meanwhile, the effects of different carbon and nitrogen sources, culture medium, temperature, photoperiod and pH on mycelial growth and spore production of F. solani were investigated. In addition, effective fungicides were screened and the concentration ratios of fungicides were optimized using response surface methodology (RSM). The experimental results showed that sucrose was the optimum carbon source for the pathogen, and the optimum temperature and pH were 25°C and pH 7, respectively, while light did no significant effect. Effective fungicides were screened, among which difenoconazole showed the strongest inhibition with EC50 of 142.773 µg/mL. The optimum fungicide concentration scheme (difenoconazole, pyraclostrobin, and thiophanate-methyl at 395.42, 781.03, and 561.11 µg/mL, respectively) was obtained using response surface methodology (RSM) to improve the inhibition rate of 92.24 ± 0.34%. This study provides basic data for the pathogen characterization of B. striata white root rot and its potential fungicides in Sichuan, China. In addition, the optimal fungicide concentration ratios were obtained through response surface methodology (RSM) optimization, which significantly enhanced the fungicidal effect and provided a scientific basis for the future control of B. striata white root rot.
摘要：
白及是我国濒危的传统药材。2020年5月，白根腐病的出现严重影响了纹状体的品质和产量，影响成都农林科学院植物苗圃约5％的植物。通过一系列的实验和评价,病原体被鉴定为镰刀菌。这是四川首次报道由F.solani引起的B.striata白色根腐病，中国。为了更好地了解这种疾病并为其控制提供数据支持，形态学的组合，本研究使用分子表征和致病性测定进行评估。同时,不同碳源和氮源的影响，培养基,温度,研究了光周期和pH值对茄子菌丝生长和孢子产生的影响。此外,采用响应面法（RSM）筛选出有效的杀菌剂，并优化杀菌剂的浓度比。实验结果表明,蔗糖是该病原菌的最佳碳源,最佳温度和pH分别为25°C和pH7，而光线没有显著影响。筛选出有效的杀菌剂,其中苯醚甲环唑表现出最强的抑制作用，EC50为142.773µg/mL。最佳杀菌剂浓度方案(苯醚甲环唑，吡唑酮酯,以及395.42、781.03和561.11µg/mL的甲基托布津，分别）使用响应面法（RSM）获得了92.24±0.34％的抑制率。本研究为四川白纹根腐病的病原鉴定及其潜在的杀菌剂提供了基础数据。中国。此外,通过响应面法(RSM)优化得到最佳杀菌剂浓度比,显著提高了杀菌效果,为今后防治纹枯病提供了科学依据。
