贵州山豆根根腐病病原菌鉴定

Identification of pathogen causing root rot of Sophora tonkinensis Radix in Guizhou

【目的】明确贵州山豆根根腐病的病原菌种类,为山豆根根腐病的防治及抗病育种提供理论基础。【方法】采用保湿培养法和组织分离法对感染根腐病的山豆根植株组织进行病原菌分离和纯化,根据柯赫氏法则对代表性菌株进行致病力测定;结合形态学和分子生物学方法对病原菌进行鉴定。【结果】从收集的病株组织样本中共分离获得200株真菌菌株,选取在PDA培养基上菌落形态差异明显的67株菌株进行ITS测序并在NCBI数据库进行BLASTn比对分析,结果显示,67株菌株中包含尖孢镰刀菌(Fusarium oxysporum)35株、茄腐镰刀菌(F.solani)7株、粉红粘帚霉(Clonostachys rosea)23株和帚状弯孢聚壳(Eutypella scoparia)2株。致病性测定结果表明,尖孢镰刀菌代表性菌株和茄腐镰刀菌代表性菌株均可侵染山豆根引起典型的根腐病症状,且茄腐镰刀菌致病性明显强于尖孢镰刀菌。结合形态学特征和分子生物学鉴定结果,确认分离得到的病原菌分别为尖孢镰刀菌和茄腐镰刀菌。【结论】贵州山豆根根腐病主要由尖孢镰刀菌和茄腐镰刀菌复合侵染引起。

【Objective】To identify the pathogen causing root rot of Sophora tonkinensis Radix in Guizhou,and to provide a theoretical basis for disease control of S.tonkinensis Radix root rot and for breeding resistant varieties.【Method】The pathogen causing root rot on S.tonkinensis Radix was isolated and purified from plant samples with root rot disease symptoms.The pathogenicity of representative strains were determined according to Koch’s law,and the pathogen strains were identified by morphological characterization and molecular biology.【Result】According to the collected diseased plant tissues,a total of 200 fungal isolates were obtained from 23 strains out of 67 strains collected,and 67 of them with different growth and morphology characters were selected for ITS sequencing on PDA media,and BLASTN comparison was conducted in NCBI database.There were 35 strains of Fusarium oxysporum,7 strains of F.solani,23 strains of Clonostachys rose and 2 strains of Eutypella scoparia.The results of pathogenicity test revealed that representative strains of F.oxysporum and F.solani could infect the root of S.tonkinensis Radix and cause typical symptoms of root rot,and F.solani showed stronger pathogenicity compared with F.oxysporum.In addition,combined with morphological characteristics and molecular biological identification results,the isolated fungal pathogens were identified as F.oxysporum and F.solani,respectively.【Conclusion】The root rot of S.tonkinensis Radix in Guizhou is mainly caused by simultaneous infection of F.oxysporum and F.solani.