Persistence of obligate parasites in natural populations, with special reference to Arabidopsis and Tragopogon

专性寄生虫的持久性、自然丰度和流行病学仍然鲜为人知。考虑到其中一些病原体造成的损失，这是值得注意的。在以前的研究中，可以表明，在一些宿主物种中，无症状感染的数量比有症状感染的数量高出20倍以上。有些物种甚至只能通过PCR检测到，从未观察到引起症状。在下一阶段，预计将重点调查拟南芥科，并将对拟南芥自然群体中卵菌病原体的发生进行大规模研究。此外，还将继续对婆罗门参体内寄生虫的生态学和流行病学进行调查。草原婆罗门参被几种活体营养型病原体（两种锈病、一种白色疱锈病、一种霜霉病、一种花药锈病）寄生，因此非常适合研究这些病原体的隐蔽持久性和共现性。拟南芥是特别感兴趣的，因为这种模式植物窝藏三种不同种类的专性寄生卵菌，拟南芥霜霉病即将成为植物病理学中最重要的专性活体营养模式生物。所提出的工作所获得的结果将产生对专性寄生虫的流行病学和生态学的基本见解，对科学界具有相当大的兴趣，并为今后与该主题有关的工作奠定坚实的基础。

The persistence, natural abundance and epidemiology of obligate parasites is still hardly known. This is remarkable, considering the losses caused by some of these pathogens. During previous studies it could be shown that in some host species, the amount of asymptomatic infections was more than 20-fold higher than the amount of symptomatic infections. Some species could even only be detected by PCR and were never observed to cause symptoms. For the next period, it is envisaged to focus on investigating Brassicaceae and large scale studies on the occurrence of oomycete pathogens in natural populations of Arabidopsis thaliana shall be done. In addition the investigations into the ecology and epidemiology of Tragopogon endoparasites shall be continued. Tragopogon pratensis is parasitized by several biotrophic pathogens (two rusts, one white blister rust, one downy mildew, one anther rust) and is therefore perfectly suited for investigating the cryptic persistence and co-occurrence of these pathogens. Arabidopsis thaliana is of particular interest, as this model plant harbours three different species of obligate parasitic oomycetes, and the Arabidopsis downy mildew is about to become the most important obligate biotrophic model organism in plant pathology. The results gained by the work proposed will yield fundamental insight into the epidemiology and ecology of obligate parasites, be of considerable interest to the scientific community and constitute a solid foundation for future work related to this topic.