Temple Brad, Pines Philip A, Hintz William E
Biology Department, University of Victoria, P.O. Box 3020 STN CSC, Victoria, BC, V8W 3N5, Canada.
Mycol Res. 2006 May;110(Pt 5):594-600. doi: 10.1016/j.mycres.2006.01.005. Epub 2006 Apr 17.
The causal agent of Dutch elm disease, Ophiostoma ulmi s. lat., has been spreading across North America since the 1920s. The population of the pathogen in Winnipeg, Manitoba, Canada was surveyed in 1993 and 2002 using a combination of RAPD marker analysis, vegetative compatibility tests, and surveys for viral double-stranded RNA (dsRNA). The data presented here show that the population, based on the vegetative compatibility and RAPD analysis, was highly genetically uniform, and has remained so for the nine-year duration of the study. The pathogen population was also monitored for the presence and spread of dsRNA molecules that, depending on identity, can be associated with a diseased phenotype and reduction of virulence in the pathogen. The current study found a very low incidence of dsRNA, and did not find any evidence for spread of these molecules through the population, even though there appeared to be no barriers to the transfer of the dsRNA between Winnipeg isolates. Despite the observation that isolates infected with the Winnipeg dsRNA showed no obvious phenotypic differences, the low incidence of dsRNA in general suggests that infected isolates do not compete as successfully as the uninfected isolates. The highly clonal nature of the pathogen population may be exploited in a control strategy.
荷兰榆树病的病原体榆长喙壳菌（Ophiostoma ulmi s. lat.）自20世纪20年代以来一直在北美传播。1993年和2002年，利用随机扩增多态性DNA（RAPD）标记分析、营养体亲和性测试以及对病毒双链RNA（dsRNA）的检测，对加拿大曼尼托巴省温尼伯市的该病原体种群进行了调查。此处呈现的数据表明，基于营养体亲和性和RAPD分析，该种群在遗传上高度一致，并且在为期九年的研究期间一直如此。还对病原体种群进行了监测，以了解dsRNA分子的存在和传播情况，这些分子根据其特性，可能与患病表型以及病原体毒力降低有关。当前研究发现dsRNA的发生率非常低，并且没有发现这些分子在种群中传播的任何证据，尽管温尼伯分离株之间的dsRNA转移似乎没有障碍。尽管观察到感染温尼伯dsRNA的分离株没有明显的表型差异，但dsRNA的低发生率总体上表明，受感染的分离株在竞争中不如未受感染的分离株成功。病原体种群的高度克隆性质可在控制策略中加以利用。
