Diversity and host specificity of the oomycete-parasitic oomycete genus Olpidiopsis

拟油藓属（Olpidiopsis）属于卵菌的早期分支，包含十多个寄生于卵菌的种类。在拟油藓属的宿主中，有几个经济上相关的卵菌属，如Aphanomyces，Pythium和Saprolegnia。然而，拟油壶菌属的物种不能离开它们的活宿主而生存，这使得必须首先培育合适的宿主，然后可以用于繁殖和诱捕拟油壶菌属的物种。然而，这个复杂的过程并没有进行很长一段时间，直到我们最近将几种Olpidiopsis与它们各自的宿主进行双重培养。尽管在这些初步试验中，只有少数描述的物种可以分离出来，但已经发现了意想不到的多样性，从而描述了一个新种，在一项未发表的研究中，可以分离出该属的另外两个物种。这表明我们开发的方法在分离该属物种方面是高效的。在这些进展的基础上，我们现在的目标是在拟议的研究中分离出广泛的Olpidiopsis物种，以测试三个主要的假设- 1）Olpidiopsis物种比目前已知的更多样化，2）Olpidiopsis物种组成和丰富度受到栖息地的强烈影响，3）Olpidiopsis物种具有高度的宿主特异性。这些假设将通过诱饵，建立双重培养，交叉感染实验，环境测序和微生物遗传学进行验证。拟议的研究结果将导致在了解卵菌寄生属Olpidiopsis的进化和生态学方面取得根本性进展，这是一个潜在的调节剂卵菌引起的疾病在植物和动物。随着双重培养的建立，一些下游研究线将变得可行，例如解剖卵菌寄生虫及其卵菌宿主的分子相互作用，以及测试Olpidiopsis菌株作为生物防治剂对抗重要的卵菌引起的疾病，例如腐霉诱导的幼苗枯萎，小龙虾瘟疫和鱼类水霉病。

The genus Olpidiopsis belongs to the early-diverging lineages of the oomycetes and contains more than a dozen species parasitic to oomycetes. Among the hosts of Olpidiopsis are several economically relevant oomycete genera, such as Aphanomyces, Pythium, and Saprolegnia. However, species of the genus Olpidiopsis cannot live without their living host, which makes it necessary to first grow a suitable host, which then can be used to propagate and bait Olpidiopsis species. However, this complicated procedure has not been carried out for a long time, until we have recently brought a few species of Olpidiopsis into dual culture with their respective hosts.Even though in these preliminary tests only few of the described species could be isolated, there was already an unexpected diversity found, leading to the description of one new species, and in an unpublished study two additional species of the genus could be isolated. This suggests that the methodology we have developed is highly efficient in isolating species of the genus. On the basis of these advances, we are now aiming in the proposed research to isolate a wide spectrum of Olpidiopsis species, to test three main hypotheses – 1) Olpidiopsis species are much more diverse than currently known, 2) Olpidiopsis species composition and richness is strongly influenced by the habitat, 3) Olpidiopsis species are highly host specific. These hypotheses will be tested using baiting, establishment of dual cultures, cross-infection experiments, environmental sequencing and phylogenetics.The findings of the proposed research will lead to fundamental progress with respect to understand the evolution and ecology of the oomycete-parasitic genus Olpidiopsis, which is a potential regulator of oomycete-caused diseases in plants and animals. With the establishment of dual cultures, several downstream research lines will become feasible, such as dissecting the molecular interaction of oomycete parasites and their oomycete hosts, as well as the testing of Olpidiopsis strains as biocontrol agent against important oomycete-caused diseases, such as Pythium-induced damping off of seedlings, crayfish plague and saprolegniosis in fish.