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知之甚少。考虑到其中一些病原体造成的损失，这是值得注意的。在以往的研究中可以发现，在某些宿主物种中，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。下一阶段拟重点开展芸苔科植物的研究，并对拟南芥自然居群中卵菌病原菌的发生进行大规模研究。此外，还应继续开展角仓鼠内寄生虫生态学和流行病学调查。草原秃鹰被几种生物营养病原体（两种锈病，一种白疱锈病，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性持久性和共存性。拟南芥（Arabidopsis thaliana）尤其值得关注，因为这种模式植物含有三种不同的专性寄生卵菌，而拟南芥霜霉病即将成为植物病理学中最重要的专性生物营养模式生物。这项工作所获得的结果将对专性寄生虫的流行病学和生态学产生根本性的见解，引起科学界的极大兴趣，并为今后与该主题相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.