病圃中烟草疫霉生理小种的鉴定

Identification of Phytophthora parasitica var. nicotianae Races in Disease Nursery

烟草疫霉(Phytophthora nicotianae)引起的烟草黑胫病是烟草生产上的毁灭性病害之一,其生理小种的分布与种植品种影响着病害的发生程度,研究疫霉病菌的生理小种十分重要。本文采用鉴别寄主在田间的抗病反应与采集菌株在TTC固体培养基平板上的颜色变化相结合的方法,对病圃中烟草黑胫病菌小种进行了鉴定。田间抗性鉴定结果表明,鉴别寄主Nicotiana nudicaulis,L8,NC1071,N.plumbagini-folia,MD609,NC95对烟草黑胫病菌表现为抗,N.stocktoii表现为中抗,Barley 21表现感病,结合已报道的8个小种的寄主反应,判断该田块黑胫病菌为0号生理小种,从该大田中随机采集的4个烟草品种潘圆黄、BL-921,CV78-5,K326上的烟草黑胫病菌,根据培养物引起TTC固体培养基颜色变化的情况,分离纯化的4个菌株均显示0号和1号小种的特征,故所鉴定病圃中烟草黑胫病病原为0号生理小种。

Black shank, caused by pathogen Phytophthora nicotianae, is one of the most destructive diseases of tobacco. Its occurrence is affected by the race distribution of pathogen and eultivar planted. The race study is critical to plant pathology and disease resistant breeding. P. nicotianae races in Yun- nan disease nursery were identified according to the resistant response of differential hosts and the pathogen color change on TYC solid medium. The 4 isolates respectively from Panyuanhuang, BL - 921, CV78 -5, K326 in this disease nursery, which can produce red metabolite with time after incu- bating Phytophthora parasitica var. nicotianae on medium, were race 0 or 1. The results of tobacco hosts reaction in disease nursery indicated that Nicotiana nudicaulis, L8, NC1071, N. plumbaginifo- lia, MD609, NC95, N. stocktoii were resistant to P. nicotianae, but Barley 21 was susceptible. Ac- cording to the reported reaction of 8 hosts, the tested pathogen was race 0. So the P. parasitica of the tested disease nursery was race 0.