甘肃陇西黄芩镰孢菌根腐病病原鉴定及其病株根部元素含量的变化

Identification of Fusarium species from Scutellaria baicalensis root rot in Longxi,Gansu Province and effects on element contents of root

为明确甘肃省陇西县黄芩根腐病镰孢菌种类,采用组织分离法对2019-2021年采集的136份病株进行分离,通过病原菌形态学特征、结合镰孢菌属通用引物、特异性引物及TEF序列分析,对病原菌进行鉴定并完成柯赫氏法则验证。结果表明,从黄芩根腐病样本上共分离到83株镰孢菌,分别为尖孢镰孢菌(39.8%)、茄病镰孢菌(36.1%)、锐顶镰孢菌(16.9%)、芬芳镰孢菌(4.8%)、木贼镰孢菌(1.2%)和柔毛镰孢菌(1.2%),其中尖孢镰孢菌和茄病镰孢菌为优势病原菌;致病性测定结果表明,不同的镰孢菌致病力不同,且同一种内各菌株的致病力差异显著;尖孢镰孢菌的相对病情指数最高,为9.0,而芬芳镰孢菌的相对病情指数最低,为1.2,木贼镰孢菌和柔毛镰孢菌没有致病性;黄芩受到镰孢菌侵染后,根部主要营养元素含量变化不显著,而微量元素锌、锰和铁的含量显著升高(P<0.05)。本研究在国内首次报道了锐顶镰孢菌和芬芳镰孢菌是黄芩根腐病的新病原菌,为科学诊断该病害、研究根腐病菌对黄芩胁迫的响应提供理论依据。

To determine the identity of pathogenic Fusarium strains causing Scutellaria baicalensis root rot disease,a total of 136 diseased roots were collected were isolated by a tissue separation method in Longxi,Gansu Province during the years of 2019 to 2021.Based on the pathogen morphological characteristics,and general primer,specific primer and translation elongation factor(TEF)sequence analysis of Fusarium,the pathogens from the collected samples were identified as belonging to 83 Fusarium strains identified as Fusarium oxysporum(39.8%),Fusarium solani(36.1%),Fusarium acuminatum(16.9%),Fusarium redolens(4.8%),Fusarium equiseti(1.2%)and Fusarium flocciferum(1.2%).Hence,F.oxysporum and F.solani were the dominant pathogens.Pathogenicity testing showed that the pathogenicity of different Fusarium species differs,and the pathogenicity of each strain within the same species also varied significantly.The relative disease index of F.oxysporum was 9.0 and was the strongest,that of F.redolens was 1.2 and was the weakest.F.equiseti and F.flocciferum displayed no pathogenicity.The major nutrient element contents in S.baicalensis roots did not change significantly after infection,while the contents of micro elements Zn,Mn and Fe increased significantly(P<0.05).This is the first report of F.acuminatum and F.redolens causing root rot on S.baicalensis in China,and these data provide a theoretical basis for scientific diagnosis of this disease and study of the response of S.baicalensis to Fusarium infection.