Endophytes and invasive plants: How do endophytic fungi affect the growth, environmental tolerance and competitive success of invasive knotweed?

入侵植物正在造成严重的生态和经济问题，因此了解是什么使这些植物如此具有竞争力和优势是很重要的。现在有越来越多的证据表明，土壤微生物在许多植物入侵中起着关键作用。然而，这些证据大多相当粗糙，我们往往不知道哪些特定的微生物组促进了植物的入侵。土壤微生物中有一类种类繁多，分布广泛，但仍鲜为人知，那就是塞巴菌目的真菌内生菌。这些物种通常很难分离和培育，因此到目前为止，对它们的生态效应进行实验测试的机会很少。在这里，我们建议进行一个项目，测试真菌内生真菌对外来节草(Fallopia SSP.)的生长、环境耐受性和入侵成功的影响，Fallopia SSP.是世界上一些最严重的入侵植物。我们将使用一种Sebacinales菌株，Sebacina herbamans，它是最近在我们团队中分离出来的。从初步工作中我们知道，草单胞菌可以强烈影响植物的生长，它发生在入侵的虎杖中，我们能够通过实验将草单胞菌接种到节藻上。我们还知道，一些(未知的)土壤微生物促进了入侵的虎杖对本地植物的优势。我们的项目将由三个互补的工作包组成：(1)实验室实验，在高度可控的条件下，我们将测试内生菌对入侵结缕草生长的影响。(2)更符合生态实际的园艺实验，我们将测试在不同环境条件下，内生菌对当地植物群落中节节草竞争能力和入侵成功的影响。(3)我们将尝试将内生菌的多样性和丰富度与虎杖入侵田间成功与否联系起来的实地调查。在前两个工作包中，我们将实验地将草链霉菌接种到结缕草植物上，我们通常通过显微镜和实时定量PCR来验证这些接种的成功，并量化内生菌定殖率。在最后的工作包中，我们将使用下一代测序方法不仅比较草本植物的分布，而且更广泛地比较广泛的入侵结缕草种群中所有与根相关的真菌的多样性。我们的项目将独特地将入侵生物学与内生菌研究结合起来，我们希望它将为内生菌生态学和植物入侵成功的决定因素提供新的见解。

Invasive plants are causing substantial ecological and economic problems, and it is therefore important to understand what makes these plants so competitive and dominant. There is now increasing evidence that soil microbes play a key role in many plant invasions. However, much of this evidence is rather coarse, and we often do not know which specific groups of microorganisms promote plant invasiveness. One particular group of soil microbes that is very diverse and widespread but still little understood are fungal endophytes of the order Sebacinales. These species are usually difficult to isolate and cultivate, and therefore opportunities for experimental tests of their ecological effects have so far been rare. Here, we propose to conduct a project that will test for the effects of fungal endophytes on the growth, environmental tolerance and invasion success of exotic knotweeds (Fallopia ssp.), some of the worst invasive plants worldwide. We will work with a Sebacinales strain, Sebacina herbamans, that was recently isolated in our group. We know from preliminary work that S. herbamans can strongly affect plant growth, that it occurs in invasive knotweed, and that we are able to experimentally inoculate knotweed with S. herbamans. We also know that some (unknown) soil microbes promote dominance of invasive knotweed over native plants. Our project will consist of three complementary work packages: (1) A lab experiment in which we will test the effects of the endophytes on the growth of invasive knotweed under highly controlled conditions. (2) A more ecologically realistic garden experiment where we will test the effects of endophytes on the competitive ability and invasion success of knotweed in native plant communities under a range of different environmental conditions. (3) A field survey in which we will attempt to associate endophyte diversities and abundances with knotweed invasion success in the field. In the first two work packages, we will experimentally inoculate knotweed plants with S. herbamans, and we generally verify the success of these inoculations, and quantify endophyte colonization rates, through microscopy and quantitative real-time PCR. In the last work package, we will use next-generation sequencing methods to compare not only the distribution of S. herbamans but more broadly the diversity of all root-associated fungi across a broad range of invasive knotweed populations. Our project will uniquely combine invasion biology with endophyte research, and we hope that it will provide novel insights both in the ecology of endophytes and the determinants of plant invasion success.