de Nooij Marianne P, van Damme Jos M M
Institute for Ecological Research, Department of Dune Research "Weevers' Duin,", Duinzoom 20A 3233 EG Oostvoorne, THE NETHERLANDS.
Evolution. 1988 Nov;42(6):1166-1171. doi: 10.1111/j.1558-5646.1988.tb04177.x.
Pathogenicity of isolates of the fungus Phomopsis subordinaria, sampled in three scarcely or heavily infected populations of Plantago lanceolata, was investigated on three different host genotypes. The expression of the pathogen appeared to be quantitative rather than qualitative in character, which suggests polygenic inheritance of host susceptibility. Significant statistical interaction between pathogen and host pointed to some degree of physiological specialization between them. None of the individual host-pathogen combinations was found to contribute significantly to the interaction. Differences in mean pathogenicity between the pathogen populations could not explain the different intensities of disease observed in the field. As the variation in susceptibility between populations of the host at the same three locations also cannot account for the differences in intensity of disease in the field, it can be concluded that environmental factors (in particular weevils that spread the disease) are important for the development of the disease. In one of the populations, the spatial scale at which variation within the pathogen occurs was determined. It appeared that the pathogen varied in pathogenicity in the field, even among scapes within an individual host plant. The consequences of this scale of variation in the pathogen are discussed for the dynamics and evolution of the pathosystem.
对从三个感染程度轻微或严重的窄叶车前种群中采集的真菌亚附生拟茎点霉分离株，在三种不同宿主基因型上进行了致病性研究。病原体的表达似乎具有数量特征而非质量特征，这表明宿主易感性是多基因遗传的。病原体与宿主之间存在显著的统计相互作用，表明它们之间存在一定程度的生理专化。未发现任何单个宿主 - 病原体组合对这种相互作用有显著贡献。病原体种群之间平均致病性的差异无法解释田间观察到的不同病害严重程度。由于在相同三个地点的宿主种群之间易感性的差异也不能解释田间病害严重程度的差异，因此可以得出结论，环境因素（特别是传播病害的象鼻虫）对病害的发生发展很重要。在其中一个种群中，确定了病原体发生变异的空间尺度。结果表明，即使在单个宿主植物的花茎之间，病原体在田间的致病性也存在差异。针对病害系统的动态和进化，讨论了病原体这种变异尺度的影响。
