Diversity and function of plant microbiomes

越来越多的人认识到，植物和包括人类在内的动物一样，不是自给自足的有机体，而是多种微生物的栖息地，包括真菌、细菌和古生菌。其中许多微生物为宿主提供了宝贵的好处，比如氮和磷等营养物质的循环，以及提供对病原体和其他压力(如干旱)的保护，以换取生活在富含碳的栖息地。植物及其相关微生物的这种相互依存关系被称为植物微生物群。在气候变化、害虫、病原体和入侵物种增加，以及随着化肥和农药使用量减少而对食物和纤维的需求增加的情况下，了解植物微生物群现在被认为是实现可持续森林和农业生态系统的关键。然而，我们对与不同植物物种相关的各种微生物及其功能的了解仍处于初级阶段，因为直到最近，由于我们缺乏研究它们的技术，许多这些微生物还无法被识别。随着分子生物学的最新进展，这意味着微生物不必在实验室中培养就可以进行研究，加上新的“组学”技术使我们能够将微生物与功能联系起来，我们将揭开植物微生物群落的复杂性。这项研究将使用各种新的分子和“组学”技术，结合稳定的同位素标记和探测方法，了解植物与其微生物群之间的关系，进而如何影响生态系统功能，以期优化这些伙伴关系，以实现可持续性。菌根(真菌-根)联盟是植物和微生物之间最普遍的联盟之一，也是植物为了生存而在很大程度上被迫形成的联盟。自然界中有两个主要的菌根组合，外生菌根(ECM)存在于大多数温带树种上，丛枝菌根(AM)存在于农作物和草本植物中。然而，作为不列颠哥伦比亚省的关键树种之一，西部红柏的不同寻常之处在于，它与形成AM的真菌形成了关系，而不是ECM。我们对雪松上形成AM的真菌的多样性知之甚少，尽管没有这些真菌，雪松就不能生存。越来越多的证据表明，植物通过根、根分泌物释放的碳塑造了微生物群落。为了加强这些伙伴关系，我们需要描述植物微生物群中完整的微生物多样性，我们还需要更好地了解植物、它们的菌根伙伴和其他密切相关的微生物之间的碳流、生化信号和分子相互作用。在未来，对健康的植物微生物组的功能的了解可能导致新的方法，例如，操纵微生物组，以改善粮食和纤维生产，保护植物免受生物和非生物胁迫。

There is growing recognition that plants, like animals, including humans, are not self-sufficient organisms, but are inhabited by a multitude of assorted microorganisms, including fungi, bacteria and archaea. Many of these microorganisms provide valuable benefits for the host, such as cycling of nutrients like nitrogen and phosphorus and providing protection against pathogens and other stresses, such as drought, in return for living in a carbon-rich habitat. This mutual dependency of plants and their associated microorganisms in known as the plant microbiome. Understanding the plant microbiome, is now recognized as being key to achieving sustainable forest and agro-ecosystems in the face of climate change, increasing pests, pathogens and invasive species coupled with increased demand for food and fibre with decreasing fertilizer and pesticide application. However, our understanding of the variety of microorganisms associated with different plant species, and their functions, is still in its infancy because until recently many of these microorganisms could not be identified because we lacked techniques to study them. With recent advances in molecular biology that mean microorganisms do not have to be grown in the lab in order to be studied, along with new “omics” technologies which enable us to link microorganisms to functions we are set to unravel the complexity of plant microbiomes. This research will use a variety of novel molecular and “omics” techniques, coupled with stable isotope labelling and probing approaches to understand the relationships between plants and their microbiome and in turn how this affects ecosystem function, with a view to optimizing these partnerships for sustainability. One of the most universal unions between plants and microbes, and one that plants are largely obliged to form for survival, is the mycorrhizal (fungus-root) alliance. There are two main mycorrhizal associations in nature, ectomycorrhizae (ECM) found on most temperate tree species and arbuscular mycorrhizae (AM), found in crops and herbaceous plants. However, one of the key tree species in BC, western redcedar is unusual in that it forms a relationship with fungi forming AM, not ECM. We know very little about the diversity of fungi forming AM on cedar, though without these fungi cedar cannot survive. There is increasing evidence that carbon released by plants through their roots, root exudates, shape microbiomes. In order to augment these partnerships we need to characterize the complete microbial diversity in plant microbiomes and we also need better understanding of the flows of carbon, biochemical signals and molecular interactions between plants, their mycorrhizal associates and other closely-associated microorganisms. In future, understanding of the functions of a healthy plant microbiome could lead to novel approaches e.g. manipulation of the microbiome, to improve food and fibre production and protect plants from biotic and abiotic stress.