一种丹参新病害的病原菌鉴定及致病力测定

 调查发现河北省安国市丹参生产区发生一种丹参新病害。为有效防治该病害,开展了丹参新病害病原菌分离鉴定及致病力测定。采用常规组织分离法,从丹参病株中分离并单孢纯化获得15个真菌分离物。柯赫氏法则证明这15个真菌分离物可造成丹参组培苗表现与田间病株相似症状,并分离获得了与丹参病株初分离物菌落形态相同的真菌菌株。显微观察发现15个病株初分离物的分生孢子梗具有明显的轮状分枝,在培养基中能够产生黑色放射状微菌核,据此将罹病丹参分离物确定为轮枝菌属真菌(Verticillium)。rDNA-ITS序列比对发现分离物与大丽轮枝菌(V. dahliae)亲缘关系最近,进一步通过特异性引物扩增证明该分离物为大丽轮枝菌。利用大丽轮枝菌落叶型和非落叶型引物扩增发现,13株分离物为落叶型菌株,2株为非落叶型菌株。人工切根接种鉴定结果表明从丹参分离的轮枝菌菌株间存在致病力差异,不同丹参品种对黄萎病存在抗病性差异。本研究首次报道了由大丽轮枝菌引起的丹参黄萎病,研究结果将为防治丹参新病害提供重要依据。

Pathogen identification and pathogenicity determination of a new disease on Salvia miltiorrhiza Bge

A new soil-borne disease of Salvia miltiorrhiza occurred in Anguo county of Hebei province in recent years. These pathogens were isolated and identified, and these pathogenicities of the isolates on S. miltiorrhiza were evaluated Fifteen fungal isolates were obtained from S. miltiorrhiza exhibiting typical symptoms of soil-borne disease, and these isolates were confirmed as the pathogens of S. miltiorrhiza by testing Koch's postulates. Under microscope, all isolates showed wheel branched conidiophores and could produce black radial microsclerotia on the media, thus, it was speculated that these isolates belong to the genus Verticillium. These isolates showed the highest internal transcribed spacer (ITS) sequence similarity with the species of V. dahliae, and were further identified as V. dahliae by PCR amplification with V. dahliae specific primers. Among them, 13 isolates were defoliated strains and 2 isolates were non-defoliated strains identified by PCR amplification with defoliated and non-defoliated specific primers. Taken together, the new soil-borne disease of S. miltiorrhiza was identified as verticillium wilt caused by V. dahliae. The artificial inoculation experiment revealed the obvious differences both in pathogenicities among V. dahliae isolates and in host resistances among the varieties of S. miltiorrhiza. To our knowledge, this is the first report of verticillium wilt of S. miltiorrhiza in China.